1.
Sonoran Desert
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It is the hottest desert in Mexico. It has an area of 260,000 square kilometers, the western portion of the United States–Mexico border passes through the Sonoran Desert. In phytogeography, the Sonoran Desert is within the Sonoran Floristic Province of the Madrean Region in southwestern North America, the desert contains a variety of unique and endemic plants and animals, such as the saguaro and organ pipe cactus. It is bounded on the west by the Peninsular Ranges, which separate it from the California chaparral and woodlands, to the north in California and northwest Arizona, the Sonoran Desert transitions to the colder-winter, higher-elevation Mojave, Great Basin, and Colorado Plateau deserts. To the east and southeast, the transition to the coniferous Arizona Mountains forests and Sierra Madre. To the south the Sonoran–Sinaloan transition subtropical dry forest is the zone from the Sonoran Desert to the tropical dry forests of the Mexican state of Sinaloa. The deserts sub-regions include the Colorado Desert of southeastern California, many ecologists now consider Shreves Vizcaíno and Magdalena regions, which lie on the western side of the Baja California Peninsula, to be a separate ecoregion, the Baja California Desert. The Pinacate National Park includes the only active Erg dune region in North America, the nearest city to the Reserva de la Biosfera el Pinacate y Gran Desierto de Altar is Puerto Peñasco in the state of Sonora, Mexico. The Sonoran Desert area southeast of Tucson and near the Mexican border is vital habitat for the population of jaguars living within the United States. Many plants not only survive, but thrive in the conditions of the Sonoran Desert. Many have evolved to have specialized adaptations to the desert climate, the Sonoran Deserts biseasonal rainfall pattern results in more plant species than any other desert in the world. The Sonoran Desert includes plant genera and species from the family, palm family, cactus family, legume family. The Sonoran is the place in the world where the famous saguaro cactus grows in the wild. Cholla, beavertail, hedgehog, fishhook, prickly pear, nightblooming cereus, creosote bush and bur sage dominate valley floors. Indigo bush and Mormon tea are other shrubs that may be found, wildflowers of the Sonoran Desert include desert sand verbena, desert sunflower, and evening primroses. Ascending from the valley up bajadas, various such as velvet mesquite, palo verde, desert ironwood, desert willow. Shrubs found at higher elevations include whitethorn acacia, fairy duster, in the desert subdivisions found on Baja California, cardon cactus, elephant tree, and boojum tree occur. The California fan palm is found in the Colorado Desert section of the Sonoran Desert and it is found at spring-fed oases, such as in Anza Borrego Desert State Park, Joshua Tree National Park, and the Kofa National Wildlife Refuge
2.
Mexico
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Mexico, officially the United Mexican States, is a federal republic in the southern half of North America. It is bordered to the north by the United States, to the south and west by the Pacific Ocean, to the southeast by Guatemala, Belize, and the Caribbean Sea, and to the east by the Gulf of Mexico. Covering almost two million square kilometers, Mexico is the sixth largest country in the Americas by total area, Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana, pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its base in Mexico-Tenochtitlan, Three centuries later, this territory became Mexico following recognition in 1821 after the colonys Mexican War of Independence. The tumultuous post-independence period was characterized by instability and many political changes. The Mexican–American War led to the cession of the extensive northern borderlands, one-third of its territory. The Pastry War, the Franco-Mexican War, a civil war, the dictatorship was overthrown in the Mexican Revolution of 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the countrys current political system. Mexico has the fifteenth largest nominal GDP and the eleventh largest by purchasing power parity, the Mexican economy is strongly linked to those of its North American Free Trade Agreement partners, especially the United States. Mexico was the first Latin American member of the Organisation for Economic Co-operation and Development and it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts. By 2050, Mexico could become the fifth or seventh largest economy. The country is considered both a power and middle power, and is often identified as an emerging global power. Due to its culture and history, Mexico ranks first in the Americas. Mexico is a country, ranking fourth in the world by biodiversity. In 2015 it was the 9th most visited country in the world, Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus and the Pacific Alliance. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely, the Valley of Mexico, and its people, the Mexica and this became the future State of Mexico as a division of New Spain prior to independence. It is generally considered to be a toponym for the valley became the primary ethnonym for the Aztec Triple Alliance as a result. After New Spain won independence from Spain, representatives decided to name the new country after its capital and this was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan
3.
Surface water
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Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water, non-saline surface water is replenished by precipitation and by recruitment from ground-water. Surface and groundwater are two entities, so they must be regarded as such. However, there is an ever-increasing need for management of the two as they are part of a system that is paramount when the demand for water exceeds the available supply. Depletion of surface and ground water sources for public consumption is caused by over-pumping, aquifers near river systems that are over-pumped have been known to deplete surface water sources as well. Research supporting this has found in numerous water budgets for a multitude of cities. Response times for an aquifer are long, however, a total ban on ground water usage during water recessions would allow surface water to retain better levels required for sustainable aquatic life. By reducing ground water pumping, the water supplies will be able to maintain their levels, as they recharge from direct precipitation, surface runoff. Environmental persistent pharmaceutical pollutant Meltwater Optimum water content for tillage Applied Hydrogeology, Fourth Edition by C. W. Fetter
4.
Groundwater
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Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is also withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is also evidence that water may also exist in the subsurface of Jupiters moon Europa. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
5.
Ecosystem
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An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles, as ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. Energy, water, nitrogen and soil minerals are other essential components of an ecosystem. The energy that flows through ecosystems is obtained primarily from the sun and it generally enters the system through photosynthesis, a process that also captures carbon from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and they also influence the quantity of plant and microbial biomass present. Ecosystems are controlled both by external and internal factors, other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can have different characteristics simply because they contain different species. The introduction of species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are controlled by them and are often subject to feedback loops. Other internal factors include disturbance, succession and the types of species present, although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Biodiversity affects ecosystem function, as do the processes of disturbance, classifying ecosystems into ecologically homogeneous units is an important step towards effective ecosystem management, but there is no single, agreed-upon way to do this. The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley, Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as The whole system, including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment. Tansley regarded ecosystems not simply as natural units, but as mental isolates, Tansley later defined the spatial extent of ecosystems using the term ecotope. G. Raymond Lindeman took these ideas one step further to suggest that the flow of energy through a lake was the driver of the ecosystem. Most mineral nutrients, on the hand, are recycled within ecosystems. Ecosystems are controlled both by external and internal factors, external factors, also called state factors, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem
6.
Agriculture
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Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
7.
Economy
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An economy is an area of the production, distribution, or trade, and consumption of goods and services by different agents in a given geographical location. Economic agents can be individuals, businesses, organizations, or governments, Economic transactions occur when two parties agree to the value or price of the transacted good or service, commonly expressed in a certain currency. Monetary transactions only account for a part of the economic domain. Economic activity is spurred by production which uses resources, labor. It has changed over time due to technology, innovation such as that which produces intellectual property and these factors give context, content, and set the conditions and parameters in which an economy functions. In other words, the domain is a social domain of human practices. A command-based economy is where political agents directly control what is produced and how it is sold, a green economy is low-carbon, resource efficient, and socially inclusive. Today the range of fields of the examining the economy revolve around the social science of economics, but may include sociology, history, anthropology. All professions, occupations, economic agents or economic activities, contribute to the economy, consumption, saving, and investment are variable components in the economy that determine macroeconomic equilibrium. There are three sectors of economic activity, primary, secondary, and tertiary. Alternate and long-standing terminology distinguishes measures of an economy expressed in real values, such as real GDP, the English words economy and economics can be traced back to the Greek word οἰκονόμος, a composite word derived from οἶκος and νέμω by way of οἰκονομία. The first recorded sense of the economy is in the phrase the management of œconomic affairs. Economy is later recorded in more senses, including thrift. The most frequently used current sense, denoting the system of a country or an area. As long as someone has been making, supplying and distributing goods or services, there has some sort of economy, economies grew larger as societies grew. The Babylonians and their city state neighbors developed forms of economics comparable to currently used civil society concepts and they developed the first known codified legal and administrative systems, complete with courts, jails, and government records. The ancient economy was based on subsistence farming. The Shekel referred to an ancient unit of weight and currency, the first usage of the term came from Mesopotamia circa 3000 BC. and referred to a specific mass of barley which related other values in a metric such as silver, bronze, copper etc
8.
Tropics
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The tropics are a region of the Earth surrounding the equator. The tropics are also referred to as the zone and the torrid zone. The tropics include all the areas on the Earth where the Sun is at a point directly overhead at least once during the solar year. The tropics are distinguished from the climatic and biomatic regions of Earth, which are the middle latitudes. Tropical is sometimes used in a sense for a tropical climate to mean warm to hot and moist year-round. Many tropical areas have a dry and wet season, the wet season, rainy season or green season, is the time of year, ranging from one or more months, when most of the average annual rainfall in a region falls. Areas with wet seasons are disseminated across portions of the tropics and subtropics, under the Köppen climate classification, for tropical climates, a wet season month is defined as a month where average precipitation is 60 millimetres or more. Tropical rainforests technically do not have dry or wet seasons, since their rainfall is distributed through the year. When the wet season occurs during the season, or summer, precipitation falls mainly during the late afternoon. The wet season is a time when air quality improves, freshwater quality improves and vegetation grows significantly, floods cause rivers to overflow their banks, and some animals to retreat to higher ground. Soil nutrients diminish and erosion increases, the incidence of malaria increases in areas where the rainy season coincides with high temperatures. Animals have adaptation and survival strategies for the wetter regime, unfortunately, the previous dry season leads to food shortages into the wet season, as the crops have yet to mature. Regions within the tropics may well not have a tropical climate, there are alpine tundra and snow-capped peaks, including Mauna Kea, Mount Kilimanjaro, and the Andes as far south as the northernmost parts of Chile and Argentina. Under the Köppen climate classification, much of the area within the tropics is classed not as tropical but as dry including the Sahara Desert. Tropical plants and animals are those native to the tropics. Tropical ecosystems may consist of rainforests, dry forests, spiny forests, desert. There are often significant areas of biodiversity, and species present, particularly in rainforests. In biogeography, the tropics are divided into Paleotropics and Neotropics, together, they are sometimes referred to as the Pantropic
9.
Water vapor
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Water vapor, water vapour or aqueous vapor, is the gaseous phase of water. It is one state of water within the hydrosphere, water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Unlike other forms of water, water vapor is invisible, under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is lighter than air and triggers convection currents that can lead to clouds, use of water vapor, as steam, has been important to humans for cooking and as a major component in energy production and transport systems since the industrial revolution. Likewise the detection of water vapor would indicate a similar distribution in other planetary systems. Water vapor is significant in that it can be evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Whenever a water molecule leaves a surface and diffuses into a surrounding gas, each individual water molecule which transitions between a more associated and a less associated state does so through the absorption or release of kinetic energy. The aggregate measurement of kinetic energy transfer is defined as thermal energy. Liquid water that becomes water vapor takes a parcel of heat with it, the amount of water vapor in the air determines how fast each molecule will return to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to the loss of water, in the US, the National Weather Service measures the actual rate of evaporation from a standardized pan open water surface outdoors, at various locations nationwide. Others do likewise around the world, the US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches per year, formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool. In some countries, the evaporation rate far exceeds the precipitation rate, evaporative cooling is restricted by atmospheric conditions. Humidity is the amount of vapor in the air. The vapor content of air is measured with devices known as hygrometers, the measurements are usually expressed as specific humidity or percent relative humidity. This condition is referred to as complete saturation. Humidity ranges from 0 gram per cubic metre in dry air to 30 grams per cubic metre when the vapor is saturated at 30 °C, another form of evaporation is sublimation, by which water molecules become gaseous directly, leaving the surface of ice without first becoming liquid water. Sublimation accounts for the slow disappearance of ice and snow at temperatures too low to cause melting
10.
Cactus
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A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek κάκτος, kaktos, Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought, many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth. Cacti show many adaptations to conserve water, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, as well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of leaves, enlarged stems carry out photosynthesis, Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka. Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch, areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular, Cactus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by long drought periods. Like other succulent plants, most cacti employ a mechanism called crassulacean acid metabolism as part of photosynthesis. Transpiration, during which carbon enters the plant and water escapes, does not take place during the day at the same time as photosynthesis. The plant stores the carbon dioxide it takes in as malic acid, retaining it until daylight returns, because transpiration takes place during the cooler, more humid night hours, water loss is significantly reduced. Many smaller cacti have globe-shaped stems, combining the highest possible volume for water storage, the tallest free-standing cactus is Pachycereus pringlei, with a maximum recorded height of 19.2 m, and the smallest is Blossfeldia liliputiana, only about 1 cm in diameter at maturity. A fully grown saguaro is said to be able to absorb as much as 200 U. S. gallons of water during a rainstorm, a few species differ significantly in appearance from most of the family. At least superficially, plants of the genus Pereskia resemble other trees and they have persistent leaves, and when older, bark-covered stems. Their areoles identify them as cacti, and in spite of their appearance, they, Pereskia is considered close to the ancestral species from which all cacti evolved. In tropical regions, other cacti grow as forest climbers and epiphytes and their stems are typically flattened, almost leaf-like in appearance, with fewer or even no spines, such as the well-known Christmas cactus or Thanksgiving cactus. Cacti have a variety of uses, many species are used as ornamental plants, others are grown for fodder or forage, cochineal is the product of an insect that lives on some cacti
11.
Drought tolerance
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Drought tolerance refers to the degree to which a plant is adapted to arid or drought conditions. Desiccation tolerance is a degree of drought tolerance. Plants naturally adapted to dry conditions are called xerophytes, drought tolerant plants typically make use of either C4 carbon fixation or crassulacean acid metabolism to fix carbon during photosynthesis. Both are improvements over the common but more basal C3 pathway in that they are more energy efficient. CAM is particularly good for arid conditions because carbon dioxide can be taken up at night, allowing the stomata to stay closed during the heat of the day and thus reducing water loss. Many adaptations for dry conditions are structural, including the following, Adaptations of the stomata to reduce water loss, water storage in succulent above-ground parts or water-filled tubers. Adaptations in the system to increase water absorption. Trichomes on the leaves to absorb atmospheric water, arid conditions can lower the yield of many crops. Plant breeding programs for improved yield during drought conditions have great importance. In landscapes in arid or drought-prone regions, drought tolerance is an important consideration in plant selection, xeriscaping is an approach to landscaping first developed in Denver, Colorado, a region with hot, dry summers. The use of drought tolerant plants is essential to a successful xeriscape, which ideally requires no supplemental irrigation
12.
Mass migration
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Mass migration refers to the migration of large groups of people from one geographical area to another. Mass migration is distinguished from individual or small scale migration, and also seasonal migration. A specific mass migration that is seen as influential to the course of history may be referred to as a great migration. Historians often identify an age of mass migration occurring from c.1850 to 1914, in long distance migration occurred at an unprecedented. There were three factors led to the age of mass migration. First, cost of migration decreased dramatically, age of mass migration usually refers to the voluntary transatlantic migration of European peasants and labourers to the Americas. Immigration from Europe accounted for about 40% of total United States population growth in the late 19th century, UNHCR estimates 14 million Hindus, Sikhs and Muslims were displaced during the partition, the largest mass migration in human history. During open border regimes, immigrants attracted by falling costs of migration, migrant selection varied over time and across sending country, depending on relative wage premium in U. S. for high/low skilled and cost of migration. In the late 20th century, migrants converge upon native-born in labor market, mass migration may also be forced migration, such as the Atlantic slave trade. Religious persecution mass migrations, such as the biblical Exodus and migration through the upper Himalayan route from the east by Purohits of Aryan, similarly, mass migrations may take place in the form of deportation. On the 15th of August 1947, the partition of British India caused the movement of 18 million people and this caused both religious and civil tensions between Hindus and Muslims. This resulted in the highest casualty rate for one migration according to the Guinness Book of World Records 2014, one million people were killed and 12 million became homeless. Human migration Great Migration Gold rush Silver rush Transatlantic migrations Urbanization in China
13.
Recorded history
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Recorded history or written history is a historical narrative based on a written record or other documented communication. Recorded history can be contrasted with other narratives of the past, for broader world history, recorded history begins with the accounts of the ancient world around the 4th millennium BC, and coincides with the invention of writing. Examples of written texts, however, can be found dating as far back as 1750 BCE in Ancient Mesopotamia, for some geographic regions or cultures, written history is limited to a relatively recent period in human history because of the limited use of written records. Because of these limits, recorded history in different contexts may refer to different periods of time depending on the historical topic. The question of the nature, and even the possibility, of a method for interpreting recorded history is raised in the philosophy of history as a question of epistemology. Prehistory traditionally refers to the span of time before recorded history, prehistory refers to the past in an area where no written records exist, or where the writing of a culture is not understood. Protohistory refers to the period between prehistory and history, after the advent of literacy in a society but before the writings of the first historians. Protohistory may also refer to the period during which a culture or civilization has not yet developed writing, more complete writing systems were preceded by proto-writing. Early examples are the Jiahu symbols, Vinča signs, early Indus script, earliest recorded history, which varies greatly in quality and reliability, deals with Pharaohs and their reigns, made by ancient Egyptians. Much of the earliest recorded history was re-discovered relatively recently due to archaeological dig sites findings, since these initial accounts, a number of different traditions have developed in different parts of the world in how to handle the writing and production of historical accounts. In China, the earliest history was recorded in oracle bone script which was deciphered, the Zuo Zhuan, attributed to Zuo Qiuming in the 5th century BCE, is the earliest written of narrative history in the world and covers the period from 722 to 468 BCE. The Classic of History is one of the Five Classics of Chinese classic texts and it is traditionally attributed to Confucius. Zhan Guo Ce was a renowned ancient Chinese historical compilation of materials on the Warring States period compiled between the 3rd and 1st centuries BCE. Sima Qian was the first in China to lay the groundwork for professional historical writing and his written work was the Shiji, a monumental lifelong achievement in literature. His work influenced every subsequent author of history in China, including the prestigious Ban family of the Eastern Han Dynasty era, Herodotus of Halicarnassus has generally been acclaimed as the father of history composing his The Histories written from 450s to the 420s BCE. However, his contemporary Thucydides is credited with having first approached history with a historical method in his work the History of the Peloponnesian War. Thucydides, unlike Herodotus, regarded history as being the product of the choices and actions of human beings, saint Augustine was influential in Christian and Western thought at the beginning of the medieval period. Through the Medieval and Renaissance periods, history was studied through a sacred or religious perspective
14.
Atacama Desert
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The Atacama Desert is a plateau in South America, covering a 1, 000-kilometre strip of land on the Pacific coast, west of the Andes mountains. It is the driest non-polar desert in the world, according to estimates, the Atacama Desert proper occupies 105,000 square kilometres, or 128,000 square kilometres if the barren lower slopes of the Andes are included. Most of the desert is composed of terrain, salt lakes, sand. The National Geographic Society considers the area of southern Peru to be part of the Atacama Desert. Peru borders it on the north and the Chilean Matorral ecoregion borders it on the south, to the east lies the less arid Central Andean dry puna ecoregion. The drier portion of this ecoregion is located south of the Loa River between the parallel Sierra Vicuña Mackenna and Cordillera Domeyko, to the north of the Loa lies the Pampa del Tamarugal. The Coastal Cliff of northern Chile west of the Chilean Coast Range is the topographic feature of the coast. The geomorphology of the Atacama Desert has been characterized as a low-relief bench similar to a giant uplifted terrace by Armijo and co-workers. The intermediate depression forms a series of basins in much of Atacama Desert south of latitude 19°30’ S. North of this latitude the intermediate depression drains into the Pacific Ocean. Although the almost total lack of precipitation is the most prominent characteristic of the Atacama Desert, in 2012, the altiplano winter brought floods to San Pedro de Atacama. On 25 March 2015, heavy rainfall affected the part of the Atacama desert. Resulting floods triggered mudflows that affected the cities of Copiapo, Tierra Amarilla, Chile, Chanaral, the Atacama Desert is commonly known as the driest non-polar place in the world, especially the surroundings of the abandoned Yungay town. The average rainfall is about 15 mm per year, although some locations, such as Arica and Iquique, moreover, some weather stations in the Atacama have never received rain. Periods of up to four years have been registered with no rainfall in the sector, delimited by the cities of Antofagasta, Calama and Copiapó. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971, the Atacama Desert may be the oldest desert on earth, and has experienced extreme hyperaridity for at least 3 million years, making it the oldest continuously arid region on earth. The long history of aridity raises the possibility that supergene mineralisation, under the conditions, can form in arid environments. This desert is so arid, many mountains higher than 6,000 m are free of glaciers. Only the highest peaks have some permanent snow coverage, the southern part of the desert, between 25 and 27°S, may have been glacier-free throughout the Quaternary, though permafrost extends down to an altitude of 4,400 m and is continuous above 5,600 m
15.
Chile
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Chile, officially the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez, Desventuradas, and Easter Island in Oceania. Chile also claims about 1,250,000 square kilometres of Antarctica, the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. Southern Chile is rich in forests and grazing lands, and features a string of volcanoes and lakes, the southern coast is a labyrinth of fjords, inlets, canals, twisting peninsulas, and islands. Spain conquered and colonized Chile in the century, replacing Inca rule in northern and central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a relatively stable authoritarian republic, in the 1960s and 1970s the country experienced severe left-right political polarization and turmoil. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a coalition which ruled through four presidencies until 2010. Chile is today one of South Americas most stable and prosperous nations and it leads Latin American nations in rankings of human development, competitiveness, income per capita, globalization, state of peace, economic freedom, and low perception of corruption. It also ranks high regionally in sustainability of the state, Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile, another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a locally known as trile. The Spanish conquistadors heard about this name from the Incas, ultimately, Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such. The older spelling Chili was in use in English until at least 1900 before switching over to Chile, stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating Native Americans settled in fertile valleys, settlement sites from very early human habitation include Monte Verde, Cueva del Milodon and the Pali Aike Craters lava tube. They fought against the Sapa Inca Tupac Yupanqui and his army, the result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. The next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, the Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting. The conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarros lieutenants, who founded the city of Santiago on 12 February 1541. Although the Spanish did not find the gold and silver they sought, they recognized the agricultural potential of Chiles central valley
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Precipitation
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In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel, Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and precipitates. Thus, fog and mist are not precipitation but suspensions, because the vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated, Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers, moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. This process is active when freezing rain is occurring. A stationary front is often present near the area of freezing rain, provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. Eventually, the droplets will grow large enough to form raindrops. Lake-effect snowfall can be locally heavy, thundersnow is possible within a cyclones comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation, on the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. The movement of the trough, or intertropical convergence zone. Precipitation is a component of the water cycle, and is responsible for depositing the fresh water on the planet. Approximately 505,000 cubic kilometres of water falls as precipitation each year,398,000 cubic kilometres of it over the oceans and 107,000 cubic kilometres over land. Given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres, Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Precipitation may occur on celestial bodies, e. g. when it gets cold, Mars has precipitation which most likely takes the form of frost. Precipitation is a component of the water cycle, and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 km3 of water falls as precipitation each year,398,000 km3 of it over the oceans, given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective, stratiform, and orographic rainfall, Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice
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Convective
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Convection is the movement of groups of molecules within fluids such as liquids or gases, and within rheids. Convection takes place through advection, diffusion or both, convection cannot take place in solids because neither bulk current flows nor significant diffusion can take place in solids. Diffusion of heat can take place in solids, but that is called heat conduction, convective heat transfer is one of the major types of heat transfer, and convection is also a major mode of mass transfer in fluids. In the context of heat and mass transfer, the convection is used to refer to the sum of advective and diffusive transfer. In common use the term convection may refer loosely to heat transfer by convection, as opposed to mass transfer by convection, sometimes convection is even used to refer specifically to free heat convection as opposed to forced heat convection. However, in mechanics the correct use of the word is the general sense, convection can be qualified in terms of being natural, forced, gravitational, granular, or thermomagnetic. It may also be said to be due to combustion, capillary action, or Marangoni, heat transfer by natural convection plays a role in the structure of Earths atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be seen as clouds, natural convection also plays a role in stellar physics. The word convection may have different but related usages in different scientific or engineering contexts or applications. The broader sense is in fluid mechanics, where convection refers to the motion of fluid regardless of cause, however, in thermodynamics convection often refers specifically to heat transfer by convection. Additionally, convection includes fluid movement both by bulk motion and by the motion of individual particles, however, in some cases, convection is taken to mean only advective phenomena. Convection occurs on a scale in atmospheres, oceans, planetary mantles. Fluid movement during convection may be slow, or it may be obvious and rapid. On astronomical scales, convection of gas and dust is thought to occur in the disks of black holes. Convective heat transfer is a mechanism of heat transfer occurring because of bulk motion of fluids, heat is the entity of interest being advected, and diffused. Heat is transferred by convection in numerous examples of naturally occurring fluid flow, such as, wind, oceanic currents, convection is also used in engineering practices of homes, industrial processes, cooling of equipment, etc. The rate of heat transfer may be improved by the use of a heat sink. For instance, a typical computer CPU will have a fan to ensure its operating temperature is kept within tolerable limits
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Stratus cloud
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Stratus clouds are low-level clouds characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds that are formed by rising thermals. More specifically, the term stratus is used to describe flat, hazy, the word stratus comes from the Latin prefix strato-, meaning layer. Stratus clouds may produce a light drizzle or an amount of snow. These clouds are essentially above-ground fog formed either through the lifting of morning fog or through cold air moving at low altitudes over a region, some call these clouds high fog for the fog-like cloud. While light rain may fall, this cloud does not indicate much meteorological activity, Stratus clouds form when a sheet of warm, moist air lifts off the ground and depressurizes, following the lapse rate. This causes the relative humidity to increase due to the adiabatic cooling, Stratus clouds look like featureless gray to white sheets of cloud. They can be composed of droplets, supercooled water droplets. Stratus nebulosus clouds appear as a featureless or nebulous veil or layer of clouds with no distinctive features or structure. They are found at low altitudes, and is a sign of atmospheric stability. Stratus nebulosus may produce light drizzle, or flakes of snow, Stratus fractus clouds on the other hand, appear with an irregular shape, and forms with a clearly fragmented or ragged appearance. They mostly appear under the precipitation of major rain-bearing clouds and these are the nimbostratus clouds, and the cumulonimbus clouds, and are classified as pannus clouds. Stratus fractus can also form beside mountain slopes, without the presence of nimbus clouds, Stratus fractus are not divided into varieties, but stratus nebulosus on the other hand, are divided into two. The Stratus opacus variety appears as a nebulous or milky sheet of the nebulosus species, Stratus Translucidus is another variety of the nebulosus species. These clouds are considered more thin than the opacus variety because this cloud is rather translucent, Stratus clouds only have one pattern-based variety. This is the stratus undulatus variety, mild undulations can be observed from this cloud, only associated by the nebulosus species. Though rare, this formation is caused by disturbances on the gentle wind shear. Stratus undulatus clouds are common on stratus stratocumulomutatus clouds where the wind is stronger as height increases. Stratus cumulogenitus clouds occur when the base of cumulus clouds spreads and this can also occur on nimbostratus clouds and on cumulonimbus clouds
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Orographic lift
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Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, precipitation induced by orographic lift occurs in many places throughout the world. Examples include, The Mogollon Rim in central Arizona The western slope of the Sierra Nevada range in California The mountains near Baja California North – specifically La Bocana to Laguna Hanson, the windward slopes of Khasi and Jayantia Hills in the state of Meghalaya in India. The Western Highlands of Yemen, which receive by far the most rain in Arabia, the Western Ghats that run along Indias western coast. The Great Dividing Range of Eastern and South Eastern Australia which forces uplift of moist air originating from the ocean to the east, the mountains of New Zealand, which faces a prevailing westerly flow off the Tasman Sea. The mountains of western Tasmania which also face a prevailing westerly flow, the southern Andes, which faces a prevailing westerly flow off the Pacific Ocean. The Northwestern United States and Canada see prevailing westerly flow off the northern Pacific Ocean, places on the sea-facing side of coastal mountains see in excess of 140 inches of precipitation per year. These locales are on the side of the mountains which are in the path of storm systems, the ski country region of New York and Pennsylvania, particularly with lake effect snows. Transylvania County, North Carolina, which gets the most rainfall of anywhere in the Eastern U. S, the Appalachian Mountains in West Virginia. Table Mountain, Cape Town, South Africa, the Front Range Foothills of Northern Colorado – west of Boulder to Golden as storms pass by. Winter storms can produce 5–6 feet of snow, the highest precipitation amounts are found slightly upwind from the prevailing winds at the crests of mountain ranges, where they relieve and therefore the upward lifting is greatest. As the air descends the lee side of the mountain, it warms and dries, on the lee side of the mountains, sometimes as little as 15 miles away from high precipitation zones, annual precipitation can be as low as 8 inches per year. The entire island of Kahoolawe is in the shadow of Maui North East England is in the rain shadow of the Pennines. This explains the significant differences between the rainfall in the North West and North East, the Judean Desert in the Land of Israel and the Dead Sea. Downslope winds occur on the side of mountain barriers when a stable air mass is carried over the mountain by strong winds that increase in strength with height. Moisture is removed and latent heat released as the air mass is orographically lifted, as the air mass descends, it is compression heated. As air flows over mountain barriers, orographic lift can create a variety of cloud effects, orographic fog is formed as the air rises up the slope and will often envelope the summit. When the air is humid, some of the moisture will fall on the windward slope, when there is a high wind, a banner cloud is formed downwind of the upper slopes of isolated, steep-sided mountains
20.
Pressure system
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A pressure system is a relative peak or lull in the sea level pressure distribution. The surface pressure at sea level varies minimally, with the lowest value measured 870.0 hectopascals, pressure systems cause weather experienced locally. Pressure systems are analyzed by those in the field of meteorology within surface weather maps, a low-pressure area, or low, is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in upper levels of the troposphere, the formation process of a low-pressure area is known as cyclogenesis. Thermal lows form due to localized heating caused by greater sunshine over deserts, since localized areas of warm air are less dense than their surroundings, this warmer air rises, which lowers atmospheric pressure near that portion of the Earths surface. Large-scale thermal lows over continents help create pressure gradients that drive monsoon circulations, low-pressure areas can also form due to organized thunderstorm activity over warm water. When such an occurrence occurs over the tropics in concert with the Intertropical Convergence Zone, monsoon troughs reach their northerly extent in August and their southerly extent in February. When a convective low acquires a well-defined circulation in the tropics it is termed a tropical cyclone, tropical cyclones can form during any month of the year globally, but can occur in either the northern hemisphere or the southern hemisphere during November. Atmospheric lift caused by low-level wind convergence into the surface low brings clouds, the low-pressure areas cloudy skies act to minimize diurnal temperature extremes. Since clouds reflect sunlight, incoming solar radiation is less. At night, the effect of clouds on outgoing longwave radiation, such as heat energy from the surface. The stronger the area of low pressure the stronger the winds experienced in its vicinity, around the world, low-pressure systems are most frequently located over the Tibetan Plateau and in the lee of the Rocky mountains. In Europe, recurring low-pressure weather systems are known as depressions. The lowest recorded barometric pressure was 870 hectopascals, occurred in the Western Pacific during Typhoon Tip on 12 October 1979. High-pressure systems are associated with light winds at the surface and subsidence through the lower portion of the troposphere. In general, subsidence will dry out an air mass by adiabatic or compressional heating, thus, high pressure typically brings clear skies. During the day, since no clouds are present to reflect sunlight, there is more incoming solar radiation. At night, the absence of means that outgoing longwave radiation is not absorbed
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Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
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High-pressure area
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A high-pressure area, high or anticyclone is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward from the higher areas near their centers towards the lower pressure areas further from their centers. Viewed from above this twist in wind direction is in the direction as the rotation of the planet. The strongest high-pressure areas are associated with air masses which push away out of polar regions during the winter when there is less sun to warm neighboring regions. These Highs change character and weaken once they move further over relatively warmer water bodies, many of the features of Highs may be understood in context of middle- or meso-scale and relatively enduring dynamics of a planets atmospheric circulation. For example, massive atmospheric subsidences occur as part of the branches of Ferrel cells. Hadley cells help form the ridge, steer tropical waves. The subtropical ridge also helps form most of the worlds deserts, on English-language weather maps, high-pressure centers are identified by the letter H. Weather maps in other languages may use different letters or symbols. The direction of flow around an atmospheric high-pressure area and a low-pressure area, as seen from above. High-pressure systems rotate clockwise in the northern Hemisphere, low-pressure systems rotate counterclockwise in the southern hemisphere, the scientific terms in English used to describe the weather systems generated by highs and lows were introduced in the mid-1800s, mostly by the British. The scientific theories which explain the general phenomena originated about two centuries earlier, the term Cyclone was coined by Henry Piddington of the British East India Company to describe the devastating storm of December 1789 in Coringa, India. A cyclone forms around a low-pressure area, anticyclone, the term for the kind of weather around a high-pressure area, was coined in 1877 by Francis Galton to indicate an area whose winds revolved in the opposite direction of a cyclone. In British English, the direction of clockwise is referred to as anticlockwise. So, both the earth and winds around a low-pressure area rotate counter-clockwise in the hemisphere. The opposite to two cases occurs in the case of a high. These results derive from the Coriolis effect, that explains in detail the physics. High-pressure systems form due to motion through the troposphere, the atmospheric layer where weather occurs. Preferred areas within a flow pattern in higher levels of the troposphere are beneath the western side of troughs
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Wet season
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The rainy season, or monsoon season, is the time of year when most of a regions average annual rainfall occurs. It usually lasts one or more months, the term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics, under the Köppen climate classification, for tropical climates, a wet season month is defined as a month where average precipitation is 60 millimetres or more. In contrast to areas with savanna climates and monsoon regimes, Mediterranean climates have wet winters, some areas with pronounced rainy seasons will see a break in rainfall mid-season, when the intertropical convergence zone or monsoon trough moves to higher latitudes in the middle of the warm season. When the wet season occurs during a season, or summer, precipitation falls mainly during the late afternoon. In the wet season, air quality improves, fresh water quality improves, rivers overflow their banks, and some animals retreat to higher ground. Soil nutrients diminish and erosion increases, the incidence of malaria increases in areas where the rainy season coincides with high temperatures, particularly in tropical areas. Some animals have adaptation and survival strategies for the wet season, often, the previous dry season leads to food shortages in the wet season, as the crops have yet to mature. In areas where the rainfall is associated with a wind shift. Further, much of the total each day occurs in the first minutes of the downpour. However, since rain forests have rainfall spread evenly through the year and it is different for places with a Mediterranean climate. This shift in the jet stream brings much of the precipitation to the region. The peninsula of Italy has weather very similar to the western United States in this regard, areas with a savanna climate in Sub-Saharan Africa, such as Ghana, Burkina Faso, Darfur, Eritrea, Ethiopia, and Botswana have a distinct rainy season. Also within the climate regime, Florida and South Texas have a rainy season. Northern Guyana has two wet seasons, one in spring and the other in early winter. In western Africa, there are two rainy seasons across southern sections, but only one across the north. Within the Mediterranean climate regime, the west coast of the United States and the Mediterranean coastline of Italy, Greece, similarly, the wet season in the Negev desert of Israel extends from October through May. At the boundary between the Mediterranean and monsoon climates lies the Sonoran desert, which receives the two rainy seasons associated with each climate regime, the wet season is known by many different local names throughout the world
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Season
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A season is a division of the year marked by changes in weather, ecology and hours of daylight. Seasons result from the orbit of the Earth around the Sun. During May, June, and July, the northern hemisphere is exposed to direct sunlight because the hemisphere faces the sun. The same is true of the hemisphere in November, December. It is the tilt of the Earth that causes the Sun to be higher in the sky during the months which increases the solar flux. However, due to lag, June, July, and August are the hottest months in the northern hemisphere and December, January. In temperate and subpolar regions, four calendar-based seasons are recognized, spring, summer, autumn or fall. Ecologists often use a model for temperate climate regions, prevernal, vernal, estival, serotinal, autumnal. Many tropical regions have two seasons, the rainy, wet, or monsoon season and the dry season, some have a third cool, mild, or harmattan season. Seasons often held special significance for agrarian societies, whose lives revolved around planting and harvest times, in some parts of the world, some other seasons capture the timing of important ecological events such as hurricane season, tornado season, and wildfire season. The most historically important of these are the three seasons—flood, growth, and low water—which were previously defined by the annual flooding of the Nile in Egypt. The seasons result from the Earths axis of rotation being tilted with respect to its orbital plane by an angle of approximately 23.5 degrees, regardless of the time of year, the northern and southern hemispheres always experience opposite seasons. This is because during summer or winter, one part of the planet is directly exposed to the rays of the Sun than the other. For approximately half of the year, the northern hemisphere tips toward the Sun, for the other half of the year, the same happens, but in the southern hemisphere instead of the northern, with the maximum around December 21. The two instants when the Sun is directly overhead at the Equator are the equinoxes. Also at that moment, both the North Pole and the South Pole of the Earth are just on the terminator, and hence day and night are equally divided between the northern and southern hemispheres. Around the March equinox, the northern hemisphere will be experiencing spring as the hours of daylight increase, the effect of axial tilt is observable as the change in day length and altitude of the Sun at noon during a year. Between this effect and the daylight hours, the axial tilt of the Earth accounts for most of the seasonal variation in climate in both hemispheres
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Intertropical Convergence Zone
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The Intertropical Convergence Zone, known by sailors as the doldrums, is the area encircling the earth near the equator where the northeast and southeast trade winds converge. When it lies near the equator, it is called the near-equatorial trough, where the ITCZ is drawn into and merges with a monsoonal circulation, it is sometimes referred to as a monsoon trough, a usage more common in Australia and parts of Asia. In the seamens speech the zone is referred to as the doldrums because of its weather patterns with stagnant calms. The ITCZ appears as a band of clouds, usually thunderstorms, in the Northern Hemisphere, the trade winds move in a southwestern direction from the northeast, while in the Southern Hemisphere, they move northwestward from the southeast. When the ITCZ is positioned north or south of the equator, for instance, when the ITCZ is situated north of the equator, the southeast trade wind changes to a southwest wind as it crosses the equator. The ITCZ is formed by vertical motion largely appearing as convective activity of thunderstorms driven by heating, which effectively draw air in. The ITCZ is effectively a tracer of the branch of the Hadley cell. The dry descending branch is the horse latitudes, the location of the intertropical convergence zone varies over time with the seasons. Over land, it moves back and forth across the following the suns zenith point. Over the oceans, where the convergence zone is better defined, sometimes, a double ITCZ forms, with one located north and another south of the equator, one of which is usually stronger than the other. When this occurs, a ridge of high pressure forms between the two convergence zones. The South Pacific convergence zone is a reverse-oriented, or west-northwest to east-southeast aligned and it lies just south of the equator during the Southern Hemisphere warm season, but can be more extratropical in nature, especially east of the International Date Line. It is considered the largest and most important piece of the ITCZ, longer term changes in the intertropical convergence zone can result in severe droughts or flooding in nearby areas. In some cases, the ITCZ may become narrow, especially when it moves away from the equator, there appears to be a 15- to 25-day cycle in thunderstorm activity along the ITCZ, which is roughly half the wavelength of the Madden–Julian oscillation. Within the ITCZ the average winds are slight, unlike the north and south of the equator where the trade winds feed. Early sailors named this belt of calm the doldrums because of the inactivity, to find oneself becalmed in this region in a hot and muggy climate could mean death in an era when wind was the only effective way to propel ships across the ocean. Even today leisure and competitive sailors attempt to cross the zone as quickly as possible as the erratic weather and wind patterns may cause unexpected delays. Tropical cyclogenesis depends upon low-level vorticity as one of its six requirements, surges of higher pressure from high latitudes can enhance tropical disturbances along its axis
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Monsoon trough
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Westerly monsoon winds lie in its equatorward portion while easterly trade winds exist poleward of the trough. Right along its axis, heavy rains can be found which usher in the peak of a locations respective rainy season, as it passes poleward of a location, hot and dry conditions develop. The monsoon trough plays a role in creating many of the worlds rainforests, the term monsoon trough is most commonly used in monsoonal regions of the Western Pacific such as Asia and Australia. The migration of the ITCZ/monsoon trough into a landmass heralds the beginning of the rainy season during summer months. Depressions and tropical cyclones form in the vicinity of the monsoon trough. Monsoon troughing in the western Pacific reaches its zenith in latitude during the summer when the wintertime surface ridge in the opposite hemisphere is the strongest. It can reach as far as the 40th parallel in East Asia during August and its poleward progression is accelerated by the onset of the summer monsoon which is characterized by the development of lower air pressure over the warmest part of the various continents. In the Southern Hemisphere, the monsoon trough associated with the Australian monsoon reaches its most southerly latitude in February, increases in the relative vorticity, or spin, with the monsoon trough are normally a product of increased wind convergence within the convergence zone of the monsoon trough. Wind surges can lead to increase in convergence. A strengthening or equatorward movement in the ridge can cause a strengthening of a monsoon trough as a wind surge moves towards the location of the monsoon trough. A key way of detecting whether a wind surge has reached a trough is the formation of a burst of thunderstorms within the monsoon trough. If a circulation forms within the trough, it is able to compete with the neighboring thermal low over the continent. Such a circulation which is broad in nature within a trough is known as a monsoon depression. In the Northern Hemisphere, monsoon depressions are generally asymmetric, light and variable winds cover a large area near their center, while bands of showers and thunderstorms develop within their area of circulation. Even though these systems can develop over land, the portions of monsoon depressions are similar to tropical cyclones. In India, for example,6 to 7 monsoon depressions move across the country yearly, monsoon depressions are efficient rainfall producers, and can cause a years worth of rainfall when they move through drier areas such as the outback of Australia. Its abrupt movement to the north between May and June is coincident with the beginning of the regime and rainy seasons across South. This convergence zone has been linked to prolonged heavy rain events in the Yangtze river as well as northern China and its presence has also been linked to the peak of the rainy season in locations within Australia
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Zebra
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Zebras are several species of African equids united by their distinctive black and white striped coats. Their stripes come in different patterns, unique to each individual and they are generally social animals that live in small harems to large herds. Unlike their closest relatives, horses and donkeys, zebras have never truly domesticated. There are three species of zebras, the zebra, the Grévys zebra and the mountain zebra. The plains zebra and the mountain zebra belong to the subgenus Hippotigris, the latter resembles an ass, to which it is closely related, while the former two are more horse-like. All three belong to the genus Equus, along with other living equids, the unique stripes of zebras make them one of the animals most familiar to people. They occur in a variety of habitats, such as grasslands, savannas, woodlands, thorny scrublands, mountains, however, various anthropogenic factors have had a severe impact on zebra populations, in particular hunting for skins and habitat destruction. Grévys zebra and the mountain zebra are endangered, the name zebra in English dates back to c. 1600, from Italian zebra, perhaps from Portuguese, which in turn is said to be Congolese, the Encarta Dictionary says its ultimate origin is uncertain, but perhaps it may come from Latin equiferus meaning wild horse, from equus and ferus. The pronunciation with an initial vowel remains standard in the United States. Zebras evolved among the Old World horses within the last 4 million years and it has been suggested that zebras are polyphyletic and that striped equids evolved more than once. Extensive stripes are posited to have been of use to equids that live in low densities in deserts or ones that live in colder climates with shaggy coats. However, molecular evidence supports zebras as a monophyletic lineage, collectively, two of the species have eight subspecies. Zebra populations are diverse, and the relationships between, and the status of, several of the subspecies are not well known. It, or particular subspecies of it, have also known as the common zebra, the dauw, Burchells zebra, Chapmans zebra, Wahlbergs zebra, Selous zebra, Grants zebra, Boehms zebra. The mountain zebra of southwest Africa tends to have a coat with a white belly. It has two subspecies and is classified as vulnerable, Grévys zebra is the largest type, with a long, narrow head, making it appear rather mule-like. It is an inhabitant of the grasslands of Ethiopia and northern Kenya
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Elephant
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Elephants are large mammals of the family Elephantidae and the order Proboscidea. Three species are recognised, the African bush elephant, the African forest elephant, Elephants are scattered throughout sub-Saharan Africa, South Asia, and Southeast Asia. Elephantidae is the surviving family of the order Proboscidea, other, now extinct, members of the order include deinotheres, gomphotheres, mammoths. Male African elephants are the largest extant terrestrial animals and can reach a height of 4 m, all elephants have several distinctive features, the most notable of which is a long trunk or proboscis, used for many purposes, particularly breathing, lifting water, and grasping objects. Their incisors grow into tusks, which can serve as weapons and as tools for moving objects, Elephants large ear flaps help to control their body temperature. Their pillar-like legs can carry their great weight, African elephants have larger ears and concave backs while Asian elephants have smaller ears and convex or level backs. Elephants are herbivorous and can be found in different habitats including savannahs, forests, deserts and they prefer to stay near water. They are considered to be keystone species due to their impact on their environments, other animals tend to keep their distance from elephants while predators, such as lions, tigers, hyenas, and wild dogs, usually target only young elephants. Females tend to live in groups, which can consist of one female with her calves or several related females with offspring. The groups are led by a known as the matriarch. Elephants have a society in which multiple family groups come together to socialise. Males leave their family groups when they reach puberty and may live alone or with other males, calves are the centre of attention in their family groups and rely on their mothers for as long as three years. Elephants can live up to 70 years in the wild and they communicate by touch, sight, smell, and sound, elephants use infrasound, and seismic communication over long distances. Elephant intelligence has been compared with that of primates and cetaceans and they appear to have self-awareness and show empathy for dying or dead individuals of their kind. African elephants are listed as vulnerable by the International Union for Conservation of Nature while the Asian elephant is classed as endangered, one of the biggest threats to elephant populations is the ivory trade, as the animals are poached for their ivory tusks. Other threats to elephants include habitat destruction and conflicts with local people. Elephants are used as working animals in Asia, in the past, they were used in war, today, they are often controversially put on display in zoos, or exploited for entertainment in circuses. Elephants are highly recognisable and have featured in art, folklore, religion, literature
29.
Wildebeest
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The wildebeests, also called gnus, are a genus of antelopes, scientific name Connochaetes. They belong to the family Bovidae, which includes antelopes, cattle, goats, sheep, Connochaetes includes two species, both native to Africa, the black wildebeest, or white-tailed gnu, and the blue wildebeest, or brindled gnu. Fossil records suggest these two species diverged about one years ago, resulting in a northern and a southern species. The most obvious way of telling the two species apart are the differences in their colouring and in the way their horns are oriented. In East Africa, the blue wildebeest is the most abundant big game species, some populations perform an annual migration to new grazing grounds, but the black wildebeest is merely nomadic. Breeding in both takes place over a period of time at the end of the rainy season. Nevertheless, some fall prey to large carnivores, Wildebeest often graze in mixed herds with zebra which gives heightened awareness of potential predators. They are also alert to the signals emitted by other animals such as baboons. Wildebeest are a tourist attraction but compete with domesticated livestock for pasture and are blamed by farmers for transferring diseases and parasites to their cattle. Some illegal hunting goes on but the trend is fairly stable. The International Union for Conservation of Nature lists both as least-concern species, the wildebeest, also called the gnu is an antelope of the genus Connochaetes. Wildebeest is Dutch for wild beast or wild cattle in Afrikaans, while Connochaetes derives from the Greek words κόννος, kónnos, beard, some sources claim the name gnu originates from the Khoikhoi name for these animals, tgnu. Others contend the name and its pronunciation in English go back to the word. nu, the name Connochaetes was given by German zoologist Hinrich Lichtenstein in 1814. Wildebeest were first discovered about 1700 by Dutch settlers on their way to the interior of South Africa, due to their resemblance to wild cattle, these people called them wild ox or wildebeest. The black wildebeest was first known to westerners in the part of South Africa a century later. In the early century, one species of the wildebeest. In 1914, two races of the wildebeest were introduced, namely Gorgon a. albojubatus and G. a. mearnsi. However, in 1939, the two were again merged into a single race, Connochaetes taurinus albojubatus
30.
Amazon River
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The Amazon River, usually abbreviated to Amazon, in South America is the largest river by discharge of water in the world and, according to some authors, the longest in length. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters at Manaus, the rivers largest city. The Amazon basin is the largest drainage basin in the world, the portion of the rivers drainage basin in Brazil alone is larger than any other rivers basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the Atlantic Ocean, during what many archaeologists call the formative stage, Amazonian societies were deeply involved in the emergence of South Americas highland agrarian systems. Early human settlements were based on low-lying hills or mounds. Shell mounds were the earliest evidences of inhabitation, they represent piles of refuse and are mainly dated between 7500 and 4000 years BP. They are associated with ceramic age cultures, no preceramic shell mounds have been documented so far by archaeologists, artificial earth platforms for entire villages are the second type of mounds. They are best represented by the Marajoara culture, figurative mounds are the most recent types of occupation. There is ample evidence that the surrounding the Amazon River were home to complex and large-scale indigenous societies, mainly chiefdoms who developed large towns. Archeologists estimate that by the time the Spanish conquistador De Orellana travelled across the Amazon in 1541 and these pre-Columbian settlements created highly developed civilizations. For instance, pre-Columbian indigenous people on the island of Marajó may have developed social stratification, in order to achieve this level of development, the indigenous inhabitants of the Amazon rainforest altered the forests ecology by selective cultivation and the use of fire. Scientists argue that by burning areas of the forest repetitiously, the people caused the soil to become richer in nutrients. This created dark soil areas known as terra preta de índio, further research has hypothesized that this practice began around 11,000 years ago. Some say that its effects on forest ecology and regional climate explain the otherwise inexplicable band of rainfall through the Amazon basin. Many indigenous tribes engaged in constant warfare, james Stuart Olson wrote, The Munduruku expansion dislocated and displaced the Kawahíb, breaking the tribe down into much smaller groups. First came to the attention of Europeans in 1770 when they began a series of attacks on Brazilian settlements along the Amazon River. In March 1500, Spanish conquistador Vicente Yáñez Pinzón was the first documented European to sail up the Amazon River. Pinzón called the stream Río Santa María del Mar Dulce, later shortened to Mar Dulce, literally, sweet sea, because of its fresh water pushing out into the ocean
31.
Colombia
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Colombia, officially the Republic of Colombia, is a transcontinental country largely situated in the northwest of South America, with territories in Central America. Colombia shares a border to the northwest with Panama, to the east with Venezuela and Brazil and to the south with Ecuador and it shares its maritime limits with Costa Rica, Nicaragua, Honduras, Jamaica, Haiti and the Dominican Republic. It is a unitary, constitutional republic comprising thirty-two departments, the territory of what is now Colombia was originally inhabited by indigenous peoples including the Muisca, the Quimbaya and the Tairona. The Spanish arrived in 1499 and initiated a period of conquest and colonization ultimately creating the Viceroyalty of New Granada, independence from Spain was won in 1819, but by 1830 the Gran Colombia Federation was dissolved. What is now Colombia and Panama emerged as the Republic of New Granada, the new nation experimented with federalism as the Granadine Confederation, and then the United States of Colombia, before the Republic of Colombia was finally declared in 1886. Since the 1960s the country has suffered from an asymmetric low-intensity armed conflict, Colombia is one of the most ethnically and linguistically diverse countries in the world, and thereby possesses a rich cultural heritage. Cultural diversity has also influenced by Colombias varied geography. The urban centres are located in the highlands of the Andes mountains. Colombian territory also encompasses Amazon rainforest, tropical grassland and both Caribbean and Pacific coastlines, ecologically, it is one of the worlds 17 megadiverse countries, and the most densely biodiverse of these per square kilometer. Colombia is a power and a regional actor with the fourth-largest economy in Latin America, is part of the CIVETS group of six leading emerging markets and is an accessing member to the OECD. Colombia has an economy with macroeconomic stability and favorable growth prospects in the long run. The name Colombia is derived from the last name of Christopher Columbus and it was conceived by the Venezuelan revolutionary Francisco de Miranda as a reference to all the New World, but especially to those portions under Spanish and Portuguese rule. The name was adopted by the Republic of Colombia of 1819. When Venezuela, Ecuador and Cundinamarca came to exist as independent states, New Granada officially changed its name in 1858 to the Granadine Confederation. In 1863 the name was changed, this time to United States of Colombia. To refer to country, the Colombian government uses the terms Colombia. Owing to its location, the present territory of Colombia was a corridor of early human migration from Mesoamerica, the oldest archaeological finds are from the Pubenza and El Totumo sites in the Magdalena Valley 100 km southwest of Bogotá. These sites date from the Paleoindian period, at Puerto Hormiga and other sites, traces from the Archaic Period have been found
32.
Central America
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Central America is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. Central America is bordered by Mexico to the north, Colombia to the southeast, the Caribbean Sea to the east, Central America consists of seven countries, Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama. The combined population of Central America is between 41,739,000 and 42,688,190, Central America is a part of the Mesoamerican biodiversity hotspot, which extends from northern Guatemala through to central Panama. Due to the presence of several active faults and the Central America Volcanic Arc. Volcanic eruptions and earthquakes occur frequently, these disasters have resulted in the loss of many lives. In the Pre-Columbian era, Central America was inhabited by the peoples of Mesoamerica to the north and west. Soon after Christopher Columbuss voyages to the Americas, the Spanish began to colonize the Americas, the seven states finally became independent autonomous states, beginning with Nicaragua, Honduras, Costa Rica, and Guatemala, followed by El Salvador, then Panama, and finally Belize. Middle America is usually thought to comprise Mexico to the north of the 7 states of Central America as well as Colombia, usually the whole of the Caribbean to the north-east and sometimes the Guyanas are also included. According to one source, the term Central America was used as a synonym for Middle America as recently as 1962, in Brazil, Central America comprises all countries between Mexico and Colombia, including those in the Caribbean. Mexico, in whole or in part, is included by British people. For the people living in the 5 countries formerly part of the Federal Republic of Central America there is a distinction between the Spanish language terms América Central and Centroamérica, in the Pre-Columbian era, the northern areas of Central America were inhabited by the indigenous peoples of Mesoamerica. Most notable among these were the Mayans, who had built numerous cities throughout the region, and the Aztecs, following Christopher Columbuss voyages to the Americas, the Spanish sent many expeditions to the region, and they began their conquest of Maya territory in 1523. Soon after the conquest of the Aztec Empire, Spanish conquistador Pedro de Alvarado commenced the conquest of northern Central America for the Spanish Empire. Beginning with his arrival in Soconusco in 1523, Alvarados forces systematically conquered and subjugated most of the major Maya kingdoms, including the Kiche, Tzutujil, Pipil, and the Kaqchikel. By 1528, the conquest of Guatemala was nearly complete, with only the Petén Basin remaining outside the Spanish sphere of influence, the last independent Maya kingdoms – the Kowoj and the Itza people – were finally defeated in 1697, as part of the Spanish conquest of Petén. In 1538, Spain established the Real Audiencia of Panama, which had jurisdiction over all land from the Strait of Magellan to the Gulf of Fonseca. This entity was dissolved in 1543, and most of the territory within Central America then fell under the jurisdiction of the Audiencia Real de Guatemala. This area included the current territories of Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and the Mexican state of Chiapas, the president of the Audiencia, which had its seat in Antigua Guatemala, was the governor of the entire area
33.
Zambia
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The capital city is Lusaka, in the south-central part of Zambia. The population is concentrated mainly around Lusaka in the south and the Copperbelt Province to the northwest, originally inhabited by Khoisan peoples, the region was affected by the Bantu expansion of the thirteenth century. After visits by European explorers in the century, Zambia became the British protectorate of Northern Rhodesia towards the end of the nineteenth century. For most of the period, Zambia was governed by an administration appointed from London with the advice of the British South Africa Company. On 24 October 1964, Zambia became independent of the United Kingdom, Kaundas socialist United National Independence Party maintained power from 1964 until 1991. Kaunda played a key role in diplomacy, cooperating closely with the United States in search of solutions to conflicts in Rhodesia, Angola. From 1972 to 1991 Zambia was a one-party state with the UNIP as the legal political party under the motto One Zambia. Kaunda was succeeded by Frederick Chiluba of the social-democratic Movement for Multi-Party Democracy in 1991, beginning a period of social-economic growth, after Mwanawasas death, Rupiah Banda presided as Acting President before being elected President in 2008. Holding office for three years, Banda stepped down after his defeat in the 2011 elections by Patriotic Front party leader Michael Sata. Sata died on 28 October 2014, the second Zambian president to die in office, Guy Scott served briefly as interim president until new elections were held on 20 January 2015, in which Edgar Lungu was elected as the sixth President. In 2010, the World Bank named Zambia one of the worlds fastest economically reformed countries, the Common Market for Eastern and Southern Africa is headquartered in Lusaka. The territory of what is now Zambia was known as Northern Rhodesia from 1911 and it was renamed Zambia at independence in 1964. The new name of Zambia was derived from the Zambezi river, the area of modern Zambia is known to have been inhabited by the Khoisan until around AD300, when migrating Bantu began to settle around these areas. These early hunter-gatherer groups were either annihilated or absorbed by subsequent more organised Bantu groups. Archaeological excavation work on the Zambezi Valley and Kalambo Falls show a succession of human cultures, in particular, ancient camping site tools near the Kalambo Falls have been radiocarbon dated to more than 36,000 year ago. The fossil skull remains of Broken Hill Man, dated between 300,000 and 125,000 years BC, further shows that the area was inhabited by pre-historic man. The early history of tribes of modern-day Zambia can only be gleaned from knowledge passed down by successive generations through word of mouth, in the 12th century, major waves of Bantu-speaking immigrants arrived during the Bantu expansion. Among them, the Tonga people were the first to settle in Zambia and are believed to have come from the east near the big sea, by the late 12th century, more advanced kingdoms and empires had been established in most regions of modern-day Zambia
34.
Zimbabwe
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Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country located in southern Africa, between the Zambezi and Limpopo Rivers. It is bordered by South Africa to the south, Botswana to the west and southwest, Zambia to the northwest, although it does not border Namibia, less than 200 metres of the Zambezi River separates it from that country. The capital and largest city is Harare, a country of roughly 13 million people, Zimbabwe has 16 official languages, with English, Shona, and Ndebele the most commonly used. Since the 11th century, present-day Zimbabwe has been the site of several organised states and kingdoms as well as a route for migration. The British South Africa Company of Cecil Rhodes first demarcated the present territory during the 1890s, in 1965, the conservative white minority government unilaterally declared independence as Rhodesia. Zimbabwe then rejoined the Commonwealth of Nations—which it withdrew from in 2003 and it is a member of the United Nations, the Southern African Development Community, the African Union, and the Common Market for Eastern and Southern Africa. Robert Mugabe became Prime Minister of Zimbabwe in 1980, when his ZANU-PF party won the following the end of white minority rule. Under Mugabes authoritarian regime, the security apparatus has dominated the country. Mugabe has maintained the revolutionary socialist rhetoric from the Cold War era, the name Zimbabwe stems from a Shona term for Great Zimbabwe, an ancient ruined city in the countrys south-east whose remains are now a protected site. Two different theories address the origin of the word, many sources hold that Zimbabwe derives from dzimba-dza-mabwe, translated from the Karanga dialect of Shona as large houses of stone. The Karanga-speaking Shona people live around Great Zimbabwe in the province of Masvingo. Zimbabwe was formerly known as Southern Rhodesia, Rhodesia, and Zimbabwe Rhodesia, a further alternative, put forward by nationalists in Matabeleland, had been Matopos, referring to the Matopos Hills to the south of Bulawayo. In a 2001 interview, black nationalist Edson Zvobgo recalled that Mawema mentioned the name during a rally, and it caught hold. The black nationalist factions subsequently used the name the during the Second Chimurenga campaigns against the Rhodesian government during the Rhodesian Bush War of 1964-1979, major factions in this camp included the Zimbabwe African National Union, and the Zimbabwe African Peoples Union. Proto-Shona-speaking societies first emerged in the middle Limpopo valley in the 9th century before moving on to the Zimbabwean highlands, the Zimbabwean plateau eventually became the centre of subsequent Shona states, beginning around the 10th century. Around the early 10th century, trade developed with Arab merchants on the Indian Ocean coast, the main archaeological site uses a unique dry stone architecture. The Kingdom of Mapungubwe was the first in a series of sophisticated trade states developed in Zimbabwe by the time of the first European explorers from Portugal and they traded in gold, ivory, and copper for cloth and glass. From about 1300 until 1600, Mapungubwe was eclipsed by the Kingdom of Zimbabwe and this Shona state further refined and expanded upon Mapungubwes stone architecture, which survives to this day at the ruins of the kingdoms capital of Great Zimbabwe
35.
Mozambique
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It is separated from Madagascar by the Mozambique Channel to the east. The capital and largest city is Maputo, between the 1st and 5th centuries AD, Bantu-speaking peoples migrated from farther north and west. Swahili commercial ports existed along the coasts until the arrival of Europeans, the area was explored by Vasco da Gama in 1498 and colonised by Portugal from 1505. The country was an important place where Somali merchants enslaved the local population, after over four centuries of Portuguese rule, Mozambique gained independence in 1975, becoming the Peoples Republic of Mozambique shortly thereafter. After only two years of independence, the country descended into an intense and protracted civil war lasting from 1977 to 1992, in 1994, Mozambique held its first multiparty elections and has remained a relatively stable presidential republic. However, since 2013, following more than 20 years of peace, Mozambique is one of the poorest and most underdeveloped countries in the world. Mozambique is endowed with rich and extensive natural resources, the countrys economy is based largely on agriculture, but industry is growing, mainly food and beverages, chemical manufacturing, and aluminium and petroleum production. The countrys tourism sector is also growing, South Africa is Mozambiques main trading partner and source of foreign direct investment. Belgium, Brazil, Portugal, and Spain are also among the countrys most important economic partners, since 2001, Mozambiques annual average GDP growth has been among the worlds highest. However, the ranks among the lowest in GDP per capita, human development, measures of inequality. The only official language of Mozambique is Portuguese, which is mostly as a second language by about half of the population. Common native languages include Makhuwa, Sena, and Swahili, the countrys population of around 24 million is composed overwhelmingly of Bantu people. The largest religion in Mozambique is Christianity, with significant minorities following Islam, the island-town was the capital of the Portuguese colony until 1898, when it was moved south to Lourenço Marques. Between the 1st and 5th centuries AD, waves of Bantu-speaking people migrated from the west and north through the Zambezi River valley and then gradually into the plateau and they established agricultural communities or societies based on herding cattle. They brought with them the technology for smelting and smithing iron, from the late first millennium AD, vast Indian Ocean trade networks extended as far south into Mozambique as the ancient port town of Chibuene. Connections are evident at sites including Manyikeni for 11–14th century ties with the inland Great Zimbabwe kingdoms, from about 1500, Portuguese trading posts and forts displaced the Arabic commercial and military hegemony, becoming regular ports of call on the new European sea route to the east. The voyage of Vasco da Gama around the Cape of Good Hope in 1498 marked the Portuguese entry into trade, politics, the Portuguese attempted to legitimise and consolidate their trade and settlement positions through the creation of prazos tied to Portuguese settlement and administration. Historically within Mozambique there was slavery, Human beings were bought and sold by African tribal chiefs, Arab Muslim traders and Portuguese and other European traders as well
36.
Botswana
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Botswana, officially the Republic of Botswana, is a landlocked country located in Southern Africa. The citizens refer to themselves as Batswana, formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966. Since then, it has maintained a tradition of stable representative democracy. Botswana is topographically flat, with up to 70 percent of its territory being the Kalahari Desert and it is bordered by South Africa to the south and southeast, Namibia to the west and north, and Zimbabwe to the northeast. Its border with Zambia to the north near Kazungula is poorly defined, a mid-sized country of just over 2 million people, Botswana is one of the most sparsely populated nations in the world. Around 10 percent of the lives in the capital and largest city. The economy is dominated by mining, cattle, and tourism, Botswana boasts a GDP per capita of about $18,825 per year as of 2015, which is one of the highest in Africa. Its high gross national income gives the country a modest standard of living, Botswana is a member of the African Union, the Southern African Development Community, the Commonwealth of Nations, and the United Nations. The country has been among the hardest hit by the HIV/AIDS epidemic, the death rate due to AIDS or AIDS-related causes has fallen sharply from 2005 to 2013, and the number of new infections in children has also fallen. As of 2014, Botswana has the third-highest prevalence rate for HIV/AIDS, the history of Botswana starts more than 100,000 years ago, when the first humans inhabited the region. The original inhabitants of southern Africa were the Bushmen and Khoi peoples, both speak Khoisan languages and lived as hunter-gatherers. About a thousand years ago, large chiefdoms emerged that were later eclipsed by the Great Zimbabwe empire, around 1300 CE, peoples in present-day Transvaal began to coalesce into three main linguistic and political groups, including the Batswana. The Batswana, a term used also to all citizens of Botswana. Prior to European contact, the Batswana lived as herders and farmers under tribal rule, as groups broke off and moved to new land, new tribes were created. Some human development occurred before the colonial period, during the 1700s, the slave and ivory trades were expanding. To resist these pressures, Shaka, the king of the Zulu Empire, conquered tribes began to move northwest into Botswana, destroying everything in their path. In their efforts to re-establish themselves at the end of period, tribes began to exchange ivory and skins for guns with European traders. Christian missionaries sent from Europe also spread to the interior, often at the invitation of tribal chiefs who wanted guns, by 1880 every major village had a resident missionary, and their influence became permanent
37.
Southeast Asia
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Southeast Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies near the intersection of geological plates, with seismic and volcanic activity. Southeast Asia consists of two regions, Mainland Southeast Asia, also known historically as Indochina, comprising Vietnam, Laos, Cambodia, Thailand, Myanmar. Maritime Southeast Asia, comprising Indonesia, East Malaysia, Singapore, Philippines, East Timor, Brunei, Cocos Islands, definitions of Southeast Asia vary, but most definitions include the area represented by the countries listed below. All of the states are members of the Association of Southeast Asian Nations, the area, together with part of South Asia, was widely known as the East Indies or simply the Indies until the 20th century. Sovereignty issues exist over some territories in the South China Sea, Papua New Guinea has stated that it might join ASEAN, and is currently an observer. Southeast Asia is geographically divided into two subregions, namely Mainland Southeast Asia and Maritime Southeast Asia, Mainland Southeast Asia includes, Maritime Southeast Asia includes, The Andaman and Nicobar Islands of India are geographically considered part of Southeast Asia. Eastern Bangladesh and the Seven Sister States of India are culturally part of Southeast Asia, the eastern half of Indonesia and East Timor are considered to be biogeographically part of Oceania. Homo sapiens reached the region by around 45,000 years ago, homo floresiensis also lived in the area up until 12,000 years ago, when they became extinct. Austronesian people, who form the majority of the population in Indonesia, Malaysia, Brunei, East Timor. Solheim and others have shown evidence for a Nusantao maritime trading network ranging from Vietnam to the rest of the archipelago as early as 5000 BC to 1 AD. The peoples of Southeast Asia, especially those of Austronesian descent, have been seafarers for thousands of years and their vessels, such as the vinta, were ocean-worthy. Magellans voyage records how much more manoeuvrable their vessels were, as compared to the European ships, Passage through the Indian Ocean aided the colonisation of Madagascar by the Austronesian people, as well as commerce between West Asia and Southeast Asia. Gold from Sumatra is thought to have reached as far west as Rome and this was later replaced by Hinduism. Theravada Buddhism soon followed in 525, in the 15th century, Islamic influences began to enter. This forced the last Hindu court in Indonesia to retreat to Bali, in Mainland Southeast Asia, Burma, Cambodia and Thailand retained the Theravada form of Buddhism, brought to them from Sri Lanka. This type of Buddhism was fused with the Hindu-influenced Khmer culture, very little is known about Southeast Asian religious beliefs and practices before the advent of Indian merchants and religious influences from the 2nd century BCE onwards. Prior to the 13th century CE, Hinduism and Buddhism were the religions in Southeast Asia
38.
Northern Australia
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The term Northern Australia includes Queensland and the Northern Territory. The part of Western Australia north of latitude 26° south—a definition widely used in law, the 26th Parallel also defines the southern border of the NT, whereas much of the southern border of Queensland is defined by 29° south. Although it comprises half of the total area of Australia. However, it includes several sources of Australian exports, being coal from the Great Dividing Range in Queensland/New South Wales and it also includes major natural tourist attractions, such as Uluru, the Great Barrier Reef and the Kakadu National Park. Almost all of Northern Australia is an ancient craton that has not experienced geological upheaval since the end of the Precambrian. The only exception to this generalisation is the Wet Tropics of northern Queensland, the vast craton in the north and west contains a number of quite rugged mountain ranges, of which the highest are the MacDonnell and Musgrave Ranges on the southern border of the Northern Territory. These rise to over 1,500 metres, but the most spectacular features are the deep gorges of rivers such as the Finke. Most of the craton, however, is flat and generally low-lying with an average elevation of around 400 metres. The climate of the north of Australia ranges from arid in the south to monsoonal in the Top End, on the eastern coast, however, the climate is much more humid and ranges from humid sub-tropical to humid tropical in the Wet Tropics. For instance, in Burketown, the months May to September are rainless in over fifty percent of years, temperatures in summer are generally unpleasantly hot apart from the eastern coastal belt. Maximum temperatures elsewhere between October and April range from 30 °C in the south in April to around 40 °C in the inland Pilbara, further north, maxima are consistently around 32 °C but extreme humidity makes conditions very unpleasant. On the coast, maxima in January range from 29 °C in the south to 32 °C, with minima generally around 21 °C. In July, temperatures show a range, from 31 °C in the north to around 19 °C in the south. The above generalisations, however, mask the variability of the climate throughout the whole region. With the exception of the north of the Northern Territory. For example, at Charters Towers, the rainfall over the wet season can vary from less than 100 millimetres in 1901/1902 to over 2,000 millimetres in 1973/1974. Tropical cyclones may cross the coast anywhere in Northern Australia but are most frequent between Derby and Onslow on the west side and between Cooktown and Rockhampton on the east. Inland, variability of rainfall is related to the penetration of the monsoon, with high rainfall in seasons like 1973/1974, 1975/1976
39.
Wildfire
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A wildfire or wildland fire is a fire in an area of combustible vegetation that occurs in the countryside or rural area. Fossil charcoal indicates that wildfires began soon after the appearance of terrestrial plants 420 million years ago, wildfire’s occurrence throughout the history of terrestrial life invites conjecture that fire must have had pronounced evolutionary effects on most ecosystems flora and fauna. Earth is an intrinsically flammable planet owing to its cover of vegetation, seasonally dry climates, atmospheric oxygen, widespread lightning. Wildfires can be characterised in terms of the cause of ignition, their properties, the combustible material present. Wildfires can cause damage to property and human life, but they have beneficial effects on native vegetation, animals. Many plant species depend on the effects of fire for growth, however, wildfire in ecosystems where wildfire is uncommon or where non-native vegetation has encroached may have negative ecological effects. Wildfire behaviour and severity result from the combination of such as available fuels, physical setting. Strategies of wildfire prevention, detection and suppression have varied over the years, one common and inexpensive technique is controlled burning, permitting or even igniting smaller fires to minimise the amount of flammable material available for a potential wildfire. Vegetation may be burned periodically to maintain species diversity and frequent burning of surface fuels limits fuel accumulation. Wildland fire use is the cheapest and most ecologically appropriate policy for many forests, fuels may also be removed by logging, but fuels treatments and thinning have no effect on severe fire behaviour. Wildfires can also be started in communities experiencing shifting cultivation, where land is cleared quickly and farmed until the soil loses fertility, forested areas cleared by logging encourage the dominance of flammable grasses, and abandoned logging roads overgrown by vegetation may act as fire corridors. The most common cause of wildfires throughout the world. In Canada and northwest China, for example, lightning operates as the source of ignition. In other parts of the world, human involvement is a major contributor, in China and in the Mediterranean Basin, human carelessness is a major cause of wildfires. In the United States and Australia, the source of wildfires can be traced both to lightning strikes and to human activities. Coal seam fires burn in the thousands around the world, such as those in Burning Mountain, New South Wales, Centralia, Pennsylvania and they can also flare up unexpectedly and ignite nearby flammable material. The spread of wildfires based on the flammable material present, its vertical arrangement and moisture content. Fuel arrangement and density is governed in part by topography, as land shape determines factors such as available sunlight, overall, fire types can be generally characterized by their fuels as follows, Ground fires are fed by subterranean roots, duff and other buried organic matter
40.
Haze
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Haze is traditionally an atmospheric phenomenon where dust, smoke and other dry particles obscure the clarity of the sky. Sources for haze particles include farming, traffic, industry, seen from afar and depending upon the direction of view with respect to the sun, haze may appear brownish or bluish, while mist tends to be bluish-grey. Whereas haze often is thought of as a phenomenon of dry air, however, haze particles may act as condensation nuclei for the subsequent formation of mist droplets, such forms of haze are known as wet haze. The term haze, in literature, generally is used to denote visibility-reducing aerosols of the wet type. Such aerosols commonly arise from complex chemical reactions occur as sulfur dioxide gases emitted during combustion are converted into small droplets of sulphuric acid. The reactions are enhanced in the presence of sunlight, high relative humidity, a small component of wet haze aerosols appear to be derived from compounds released by trees, such as terpenes. For all these reasons, wet haze tends to be primarily a warm-season phenomenon, large areas of haze covering many thousands of kilometers may be produced under favorable conditions each summer. Haze often occurs when dust and smoke particles accumulate in relatively dry air, when weather conditions block the dispersal of smoke and other pollutants they concentrate and form a usually low-hanging shroud that impairs visibility and may become a respiratory health threat. Industrial pollution can result in dense haze, which is known as smog, since 1991, haze has been a particularly acute problem in Southeast Asia. The main source of the haze has been occurring in Sumatra. In response to the 1997 Southeast Asian haze, the ASEAN countries agreed on a Regional Haze Action Plan, in 2002, all ASEAN countries except Indonesia signed the Agreement on Transboundary Haze Pollution, but the pollution is still a problem today. Under the agreement the ASEAN secretariat hosts a co-ordination and support unit, during the 2013 Southeast Asian haze, Singapore experienced a record high pollution level, with the 3-hour Pollution Standards Index reaching a record high of 401. A full list of areas is available on EPAs website. Haze is no longer a domestic problem and it has become one of the causes of international disputes among neighboring countries. Haze migrates to adjacent countries and thereby pollutes other countries as well, one of the most recent problems concerned the two neighboring countries Malaysia and Indonesia. Winds blow most of the fumes across the narrow Strait of Malacca to Malaysia, the 2015 Southeast Asian haze constitutes an ongoing crisis. Haze causes issues in the area of photography, where the penetration of large amounts of dense atmosphere may be necessary to image distant subjects. This results in the effect of a loss of contrast in the subject
41.
Queensland
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Queensland is the second-largest and third-most-populous state in the Commonwealth of Australia. Situated in the north-east of the country, it is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west, to the east, Queensland is bordered by the Coral Sea and Pacific Ocean. Queensland has a population of 4,750,500, concentrated along the coast, the state is the worlds sixth largest sub-national entity, with an area of 1,852,642 km2. The capital and largest city in the state is Brisbane, Australias third largest city, often referred to as the Sunshine State, Queensland is home to 10 of Australias 30 largest cities and is the nations third largest economy. Tourism in the state, fuelled largely by its tropical climate, is a major industry. Queensland was first inhabited by Aboriginal Australians and Torres Strait Islanders, the first European to land in Queensland was Dutch navigator Willem Janszoon in 1606, who explored the west coast of the Cape York Peninsula near present-day Weipa. In 1770, Lieutenant James Cook claimed the east coast of Australia for the Kingdom of Great Britain. The colony of New South Wales was founded in 1788 by Governor Arthur Phillip at Sydney, New South Wales at that time included all of what is now Queensland, Queensland was explored in subsequent decades until the establishment of a penal colony at Brisbane in 1824 by John Oxley. Penal transportation ceased in 1839 and free settlement was allowed from 1842, the state was named in honour of Queen Victoria, who on 6 June 1859 signed Letters Patent separating the colony from New South Wales. The 6th of June is now celebrated statewide as Queensland Day. Queensland achieved statehood with the Federation of Australia on 1 January 1901, the history of Queensland spans thousands of years, encompassing both a lengthy indigenous presence, as well as the eventful times of post-European settlement. The north-eastern Australian region was explored by Dutch, Spanish and French navigators before being encountered by Lieutenant James Cook in 1770, the Australian Labor Party has its origin as a formal organisation in Queensland and the town of Barcaldine is the symbolic birthplace of the party. June 2009 marked the 150th anniversary of its creation as a colony from New South Wales. The Aboriginal occupation of Queensland is thought to predate 50,000 BC, likely via boat or land bridge across Torres Strait, during the last ice age Queenslands landscape became more arid and largely desolate, making food and other supplies scarce. This led to the worlds first seed-grinding technology, warming again made the land hospitable, which brought high rainfall along the eastern coast, stimulating the growth of the states tropical rainforests. In February 1606, Dutch navigator Willem Janszoon landed near the site of what is now Weipa and this was the first recorded landing of a European in Australia, and it also marked the first reported contact between European and Aboriginal Australian people. The region was explored by French and Spanish explorers prior to the arrival of Lieutenant James Cook in 1770. Cook claimed the east coast under instruction from King George III of the United Kingdom on 22 August 1770 at Possession Island, naming Eastern Australia, including Queensland, the Aboriginal population declined significantly after a smallpox epidemic during the late 18th century
42.
Victoria (Australia)
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Victoria is a state in southeast Australia. Victoria is Australias most densely populated state and its second-most populous state overall, most of its population is concentrated in the area surrounding Port Phillip Bay, which includes the metropolitan area of its state capital and largest city, Melbourne, Australias second-largest city. Prior to British European settlement, the area now constituting Victoria was inhabited by a number of Aboriginal peoples. With Great Britain having claimed the entire Australian continent east of the 135th meridian east in 1788, Victoria was included in the wider colony of New South Wales. The first settlement in the area occurred in 1803 at Sullivan Bay, and much of what is now Victoria was included in the Port Phillip District in 1836, Victoria was officially created as a separate colony in 1851, and achieved self-government in 1855. Politically, Victoria has 37 seats in the Australian House of Representatives and 12 seats in the Australian Senate, at state level, the Parliament of Victoria consists of the Legislative Assembly and the Legislative Council. Victoria is currently governed by the Labor Party, with Daniel Andrews the current Premier, the personal representative of the Queen of Australia in the state is the Governor of Victoria, currently Linda Dessau. Local government is concentrated in 79 municipal districts, including 33 cities, although a number of unincorporated areas still exist, Victorias total gross state product is ranked second in Australia, although Victoria is ranked fourth in terms of GSP per capita because of its limited mining activity. Culturally, Melbourne is home to a number of museums, art galleries and theatres and is described as the sporting capital of Australia. The Melbourne Cricket Ground is the largest stadium in Australia, and the host of the 1956 Summer Olympics, Victoria has eight public universities, with the oldest, the University of Melbourne, having been founded in 1853. Victoria, like Queensland, was named after Queen Victoria, who had been on the British throne for 14 years when the colony was established in 1851. The first British settlement in the later known as Victoria was established in October 1803 under Lieutenant-Governor David Collins at Sullivan Bay on Port Phillip. In the year 1826 Colonel Stewart, Captain S. Wright, fly and the brigs Dragon and Amity, took a number of convicts and a small force composed of detachments of the 3rd and 93rd regiments. Victorias next settlement was at Portland, on the south west coast of what is now Victoria, edward Henty settled Portland Bay in 1834. Melbourne was founded in 1835 by John Batman, who set up a base in Indented Head, from settlement the region around Melbourne was known as the Port Phillip District, a separately administered part of New South Wales. Shortly after the now known as Geelong was surveyed by Assistant Surveyor W. H. Smythe. And in 1838 Geelong was officially declared a town, despite earlier white settlements dating back to 1826, days later, still in 1851 gold was discovered near Ballarat, and subsequently at Bendigo. Later discoveries occurred at sites across Victoria
43.
New South Wales
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New South Wales is a state on the east coast of Australia. It borders Queensland to the north, Victoria to the south and it has a coast line with the Tasman Sea on its east side. The Australian Capital Territory is an enclave within the state, New South Wales state capital is Sydney, which is also Australias most populous city. In March 2014, the population of New South Wales was 7.5 million. Just under two-thirds of the population,4.67 million. Inhabitants of New South Wales are referred to as New South Welshmen, the Colony of New South Wales was founded as a penal colony in 1788. It originally comprised a more than half of the Australian mainland with its western boundary set at 129th meridian east in 1825, in addition, the colony also included the island territories of New Zealand, Van Diemens Land, Lord Howe Island, and Norfolk Island. During the 19th century, most of the area was detached to form separate British colonies that eventually became New Zealand. However, the Swan River Colony has never administered as part of New South Wales. Lord Howe Island remains part of New South Wales, while Norfolk Island has become a federal Territory, as have the now known as the Australian Capital Territory. The prior inhabitants of New South Wales were the Aboriginal tribes who arrived in Australia about 40,000 to 60,000 years ago, before European settlement there were an estimated 250,000 Aboriginal people in the region. The Wodi Wodi people are the custodians of the Illawarra region of South Sydney. The Bundjalung people are the custodians of parts of the northern coastal areas. The European discovery of New South Wales was made by Captain James Cook during his 1770 survey along the eastern coast of the Dutch-named continent of New Holland. In his original journal covering the survey, in triplicate to satisfy Admiralty Orders, Cook first named the land New Wales, however, in the copy held by the Admiralty, he revised the wording to New South Wales. After years of chaos and anarchy after the overthrow of Governor William Bligh, macquaries legacy is still evident today. During the 19th century, large areas were separated to form the British colonies of Tasmania, South Australia, Victoria. Responsible government was granted to the New South Wales colony in 1855, following the Treaty of Waitangi, William Hobson declared British sovereignty over New Zealand in 1840
44.
Tasmania
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Tasmania is an island state of the Commonwealth of Australia. It is located 240 km to the south of the Australian mainland, the state encompasses the main island of Tasmania, the 26th-largest island in the world, and the surrounding 334 islands. The state has a population of around 519,100, just over forty percent of which resides in the Greater Hobart precinct, Tasmanias area is 68,401 km2, of which the main island covers 64,519 km2. Though an island state, due to an error the state shares a land border with Victoria at its northernmost terrestrial point, Boundary Islet. The Bishop and Clerk Islets, about 37 km south of Macquarie Island, are the southernmost terrestrial point of the state of Tasmania, the island is believed to have been occupied by Aboriginals for 40,000 years before British colonisation. It is thought Tasmanian Aboriginals were separated from the mainland Aboriginal groups about 10,000 years ago when the sea rose to form Bass Strait. The conflict, which peaked between 1825 and 1831 and led to more than three years of law, cost the lives of almost 1100 Aboriginals and settlers. The near-destruction of Tasmanias Aboriginal population has been described by historians as an act of genocide by the British. The island was part of the Colony of New South Wales. In 1854 the present Constitution of Tasmania was passed and the year the state received permission to change its name to Tasmania. In 1901 it became a state through the process of the Federation of Australia, the state is named after Dutch explorer Abel Tasman, who made the first reported European sighting of the island on 24 November 1642. Tasman named the island Anthony van Diemens Land after his sponsor Anthony van Diemen, the name was later shortened to Van Diemens Land by the British. It was officially renamed Tasmania in honour of its first European discoverer on 1 January 1856, Tasmania was sometimes referred to as Dervon, as mentioned in the Jerilderie Letter written by the notorious Australian bushranger Ned Kelly in 1879. The colloquial expression for the state is Tassie, Tasmania is also colloquially shortened to Tas, especially when used in business names and website addresses. TAS is also the Australia Post abbreviation for the state, the reconstructed Palawa kani language name for Tasmania is Lutriwita. The island was adjoined to the mainland of Australia until the end of the last glacial period about 10,000 years ago, much of the island is composed of Jurassic dolerite intrusions through other rock types, sometimes forming large columnar joints. Tasmania has the worlds largest areas of dolerite, with many distinctive mountains, the central plateau and the southeast portions of the island are mostly dolerite. Mount Wellington above Hobart is an example, showing distinct columns known as the Organ Pipes
45.
Indian Ocean
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The Indian Ocean is the third largest of the worlds oceanic divisions, covering 70,560,000 km2. It is bounded by Asia on the north, on the west by Africa, on the east by Australia, the Indian Ocean is known as Ratnākara, the mine of gems in ancient Sanskrit literature, and as Hind Mahāsāgar, in Hindi. The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf, the oceans continental shelves are narrow, averaging 200 kilometres in width. An exception is found off Australias western coast, where the width exceeds 1,000 kilometres. The average depth of the ocean is 3,890 m and its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m deep, Sunda Trench has a depth of 7, 258–7,725 m. North of 50° south latitude, 86% of the basin is covered by pelagic sediments. The remaining 14% is layered with terrigenous sediments, glacial outwash dominates the extreme southern latitudes. The major choke points include Bab el Mandeb, Strait of Hormuz, the Lombok Strait, the Strait of Malacca, the Indian Ocean is artificially connected to the Mediterranean Sea through the Suez Canal, which is accessible via the Red Sea. All of the Indian Ocean is in the Eastern Hemisphere and the centre of the Eastern Hemisphere is in this ocean, marginal seas, gulfs, bays and straits of the Indian Ocean include, The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April, from May until October south, in the Arabian Sea the violent Monsoon brings rain to the Indian subcontinent. In the southern hemisphere, the winds are milder. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea, the Indian Ocean is the warmest ocean in the world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, Indian Ocean warming is the largest among the tropical oceans, and about 3 times faster than the warming observed in the Pacific. Research indicates that human induced greenhouse warming, and changes in the frequency, among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Godavari, Krishna, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The oceans currents are controlled by the monsoon. Two large gyres, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, during the winter monsoon, however, currents in the north are reversed. Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, north of 20° south latitude the minimum surface temperature is 22 °C, exceeding 28 °C to the east. Southward of 40° south latitude, temperatures drop quickly, surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia
46.
Aeolian processes
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Aeolian processes, also spelled eolian or æolian, pertain to wind activity in the study of geology and weather and specifically to the winds ability to shape the surface of the Earth. Winds may erode, transport, and deposit materials and are effective agents in regions with sparse vegetation, a lack of soil moisture, although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts. The term is derived from the name of the Greek god Aeolus, wind erodes the Earths surface by deflation and by abrasion. Regions which experience intense and sustained erosion are called deflation zones, most aeolian deflation zones are composed of desert pavement, a sheet-like surface of rock fragments that remains after wind and water have removed the fine particles. Almost half of Earths desert surfaces are stony deflation zones, the rock mantle in desert pavements protects the underlying material from deflation. A dark, shiny stain, called desert varnish or rock varnish, is found on the surfaces of some desert rocks that have been exposed at the surface for a long period of time. Manganese, iron oxides, hydroxides, and clay minerals form most varnishes, deflation basins, called blowouts, are hollows formed by the removal of particles by wind. Blowouts are generally small, but may be up to kilometers in diameter. In parts of Antarctica wind-blown snowflakes that are technically sediments have also caused abrasion of exposed rocks, grinding by particles carried in the wind creates grooves or small depressions. Ventifacts are rocks which have cut, and sometimes polished. Sculpted landforms, called yardangs, are up to tens of meters high, the famous Great Sphinx of Giza in Egypt may be a modified yardang. Particles are transported by winds through suspension, saltation and creeping along the ground, small particles may be held in the atmosphere in suspension. Upward currents of air support the weight of suspended particles and hold them indefinitely in the surrounding air, typical winds near Earths surface suspend particles less than 0.2 millimeters in diameter and scatter them aloft as dust or haze. Saltation is downwind movement of particles in a series of jumps or skips, saltation normally lifts sand-size particles no more than one centimeter above the ground and proceeds at one-half to one-third the speed of the wind. A saltating grain may hit other grains that jump up to continue the saltation, the grain may also hit larger grains that are too heavy to hop, but that slowly creep forward as they are pushed by saltating grains. Surface creep accounts for as much as 25 percent of grain movement in a desert, aeolian turbidity currents are better known as dust storms. Air over deserts is cooled significantly when rain passes through it and this cooler and denser air sinks toward the desert surface. When it reaches the ground, the air is deflected forward, crops, people, villages, and possibly even climates are affected by dust storms
47.
Irrigation
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Irrigation is the method in which a controlled amount of water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of crops, maintenance of landscapes. Additionally, irrigation also has a few uses in crop production. In contrast, agriculture that only on direct rainfall is referred to as rain-fed or dry land farming. Irrigation systems are used for dust suppression, disposal of sewage. Irrigation is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area, Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, archaeological investigation has found evidence of irrigation where the natural rainfall was insufficient to support crops for rainfed agriculture. Ancient Egyptians practiced Basin irrigation using the flooding of the Nile to inundate land plots which had surrounded by dykes. The flood water was held until the sediment had settled before the surplus was returned to the watercourse. The Ancient Nubians developed a form of irrigation by using a device called a sakia. Irrigation began in Nubia some time between the third and second millennium BCE and it largely depended upon the flood waters that would flow through the Nile River and other rivers in what is now the Sudan. In sub-Saharan Africa irrigation reached the Niger River region cultures and civilizations by the first or second millennium BCE and was based on wet season flooding, terrace irrigation is evidenced in pre-Columbian America, early Syria, India, and China. These canals are the earliest record of irrigation in the New World, traces of a canal possibly dating from the 5th millennium BCE were found under the 4th millennium canal. Large scale agriculture was practiced and a network of canals was used for the purpose of irrigation. Ancient Persia as far back as the 6th millennium BCE, where barley was grown in areas where the rainfall was insufficient to support such a crop. The Qanats, developed in ancient Persia in about 800 BCE, are among the oldest known irrigation methods still in use today and they are now found in Asia, the Middle East and North Africa. The system comprises a network of wells and gently sloping tunnels driven into the sides of cliffs. The noria, a wheel with clay pots around the rim powered by the flow of the stream, was first brought into use at about this time
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