In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, sleet, snow and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates", thus and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate. Two processes acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. 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, 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 occurs. A stationary front is present near the area of freezing rain and serves as the foci for forcing and rising air.
Provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. The cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible 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. Most precipitation is caused by convection; the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
Precipitation is a major component of the water cycle, is responsible for depositing the fresh water on the planet. 505,000 cubic kilometres of water falls as precipitation each year. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres, but over land it is only 715 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 other celestial bodies, e.g. when it gets cold, Mars has precipitation which most takes the form of frost, rather than rain or snow. Precipitation is a major component of the water cycle, is responsible for depositing most of the fresh water on the planet. 505,000 km3 of water falls as precipitation each year, 398,000 km3 of it over the oceans. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective and orographic rainfall.
Convective processes involve strong vertical motions that can cause the overturning of the atmosphere in that location within an hour and cause heavy precipitation, while stratiform processes involve weaker upward motions and less intense precipitation. 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. Mixtures of different types of precipitation, including types in different categories, can fall simultaneously. Liquid forms of precipitation include drizzle. Rain or drizzle that freezes on contact within a subfreezing air mass is called "freezing rain" or "freezing drizzle". Frozen forms of precipitation include snow, ice needles, ice pellets and graupel; the dew point is the temperature to which a parcel must be cooled in order to become saturated, condenses to water. Water vapor begins to condense on condensation nuclei such as dust and salt in order to form clouds. An elevated portion of a frontal zone forces broad areas of lift, which form clouds decks such as altostratus or cirrostratus.
Stratus is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. It can form due to the lifting of advection fog during breezy conditions. There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling, evaporative cooling. Adiabatic cooling occurs when air expands; the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a colder surface by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath. Evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation; the main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet lan
Yunnan is a province of the People's Republic of China. Located in Southwest China, the province spans 394,000 square kilometres and has a population of 45.7 million. The capital of the province is Kunming also known as Yunnan; the province borders the Chinese provinces Guangxi, Guizhou and the Tibet Autonomous Region, as well as the countries Vietnam and Myanmar. Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. Most of the population lives in the eastern part of the province. In the west, the altitude can vary from the mountain peaks to river valleys by as much as 3,000 metres. Yunnan has the largest diversity of plant life in China. Of the 30,000 species of higher plants in China, Yunnan has 17,000 or more. Yunnan's reserves of aluminium, lead and tin are the largest in China, there are major reserves of copper and nickel; the Han Empire first recorded diplomatic relations with the province at the end of the 2nd century BC. It became the seat of a Sino-Tibetan-speaking kingdom of Nanzhao in the 8th century AD.
Nanzhao was multi-ethnic. The Mongols conquered the region in the 13th century, with local control exercised by warlords until the 1930s. From the Yuan dynasty onward, the area was part of a central-government sponsored population movement towards the southwestern frontier, with two major waves of migrants arriving from Han-majority areas in northern and southeast China; as with other parts of China's southwest, Japanese occupation in the north during World War II forced another migration of majority Han people into the region. These two waves of migration contributed to Yunnan being one of the most ethnically diverse provinces of China, with ethnic minorities accounting for about 34 percent of its total population. Major ethnic groups include Yi, Hani, Zhuang and Miao; the Yuanmou Man, a Homo erectus fossil unearthed by railway engineers in the 1960s, has been determined to be the oldest-known hominid fossil in China. By the Neolithic period, there were human settlements in the area of Lake Dian.
These people constructed simple wooden structures. Around the 3rd century BC, the central area of Yunnan around present day Kunming was known as Dian; the Chu general Zhuang Qiao entered the region from the upper Yangtze River and set himself up as "King of Dian". He and his followers brought into Yunnan an influx of Chinese influence, the start of a long history of migration and cultural expansion. In 221 BC, Qin Shi Huang extended his authority south. Commanderies and counties were established in Yunnan. An existing road in Sichuan – the "Five Foot Way" – was extended south to around present day Qujing, in eastern Yunnan; the Han–Dian wars began under Emperor Wu. He dispatched a series of military campaigns against the Dian during the southward expansion of the Han dynasty. In 109 BC, Emperor Wu sent General Guo Chang south to Yunnan, establishing Yizhou commandery and 24 subordinate counties; the commandery seat was at Dianchi county in present-day Jinning. Another county was called "Yunnan" the first use of the name.
To expand the burgeoning trade with Burma and India, Emperor Wu sent Tang Meng to maintain and expand the Five Foot Way, renaming it "Southwest Barbarian Way". By this time, agricultural technology in Yunnan had improved markedly; the local people used bronze tools and kept a variety of livestock, including cattle, sheep, goats and dogs. Anthropologists have determined, they lived in tribal congregations, sometimes led by exiled Chinese. During the Three Kingdoms, the territory of present-day Yunnan, western Guizhou and southern Sichuan was collectively called Nanzhong; the dissolution of Chinese central authority led to increased autonomy for Yunnan and more power for the local tribal structures. In AD 225, the famed statesman Zhuge Liang led three columns into Yunnan to pacify the tribes, his seven captures of Meng Huo, a local magnate, is much celebrated in Chinese folklore. International trade flowed by din of Yunnan. In the 4th century, northern China was overrun by nomadic tribes from the north.
In the 320s, the Cuan clan migrated into Yunnan. Cuan Chen named himself king and held authority from Lake Dian known as Kunchuan. Henceforth the Cuan clan ruled eastern Yunnan for over four hundred years. Before the rise and dominance of the Nanzhao Kingdom around Yunnan in the eighth century, many local tribes and other groups sprang up. Around Lake Erhai, the Dali area, there emerged six zhao: Mengzi, Langqiong, Dengdan and Mengshe. Zhao was an indigenous non-Chinese language term meaning "king" or "kingdom." Among the six regimes Mengshe was located south of the other five. By the 730s Nanzhao had succeeded in bringing the Erhai Lake–area under its authority. In 738, the western Yunnan was united by Piluoge, the fourth king of Nanzhao, confirmed by the imperial court of the Tang dynasty as king of Yunnan. Ruling from Dali, the thirteen kings of Nanzhao ruled over more than two centuries and played a part in the dynamic relationship between China and Tibet. By the 750s, Nanzhao had taken eastern Yunnan into its empire and had become a potential rival to Tang China.
The following period saw conflicts between Tang China and Nanzhao. In 750, Nanzhao captured Yaozhou, the largest Tang settlement in Yunnan. In 751, Xianyu Zhongtong (
Gulin County is a county in the south of Sichuan Province, bordering Guizhou province to the north and east. It is under the administration of Luzhou city; the county covers 3,184 km2 with a population of 833,000 in 2008. Luzhou Gulin County Government website
Qingyang District is one of nine districts of Chengdu, the capital of Sichuan province, China. It is bordered by Jinniu District to the northeast, Jinjiang District to the southeast, Wuhou District to the south, Shuangliu County to the southwest, Wenjiang District to the west, Pidu District to the north. Qingyang has an area of 68 square kilometers and a population of 460,000. Chengdu Huangcheng Mosque Official website of Qingyang District Government
Pidu District known as Pi County or Pixian is an urbanizing district organized as part of Chengdu, the capital of the province of Sichuan, China. It presently covers an area of 437.5 square kilometers, with a total population of 756,047 during the 2010 census. It was known as the source of the best tobacco in Sichuan and is now well known for its doubanjiang, a type of spicy fermented bean sauce. Pitong, the seat of Pidu, is located 10 kilometers from downtown Chengdu, it covers an area of 437.5 square kilometers. During the Warring States period, the area of the present Pidu belonged to the state of Shu. In 314 BC, it was conquered by Qin, which organized Pi County two years in 312 BC. In the 19th century, the area was famed for the quality of its tobacco, reckoned the best in Sichuan, it is now seeking to attract electronics and IT corporations and, in 2015, applied for elevation to urban district status. The district seat is Pitong. There are 13 other towns in the district: Xipu Hongguang Anjing Tuanjie Tangchang Sandaoyan Xinminchang Huayuan Ande Tangyuan Deyuan Gucheng You`ai China National Highway 317 China National Highway 213 Official website of the Pidu Government
Chongzhou, known as Chongqing County until 1994, is a county-level city under the jurisdiction of Chengdu, the capital of Sichuan province, People's Republic of China, located about 37 kilometres west-southwest of downtown Chengdu. It is accessible by road from central Chengdu via the 65.1 km -long S8 Chengdu–Wenjiang–Qionglai Expressway, just outside the Chengdu greater ring road
China the People's Republic of China, is a country in East Asia and the world's most populous country, with a population of around 1.404 billion. Covering 9,600,000 square kilometers, it is the third- or fourth-largest country by total area. Governed by the Communist Party of China, the state exercises jurisdiction over 22 provinces, five autonomous regions, four direct-controlled municipalities, the special administrative regions of Hong Kong and Macau. China emerged as one of the world's earliest civilizations, in the fertile basin of the Yellow River in the North China Plain. For millennia, China's political system was based on hereditary monarchies, or dynasties, beginning with the semi-legendary Xia dynasty in 21st century BCE. Since China has expanded, re-unified numerous times. In the 3rd century BCE, the Qin established the first Chinese empire; the succeeding Han dynasty, which ruled from 206 BC until 220 AD, saw some of the most advanced technology at that time, including papermaking and the compass, along with agricultural and medical improvements.
The invention of gunpowder and movable type in the Tang dynasty and Northern Song completed the Four Great Inventions. Tang culture spread in Asia, as the new Silk Route brought traders to as far as Mesopotamia and Horn of Africa. Dynastic rule ended in 1912 with the Xinhai Revolution; the Chinese Civil War resulted in a division of territory in 1949, when the Communist Party of China established the People's Republic of China, a unitary one-party sovereign state on Mainland China, while the Kuomintang-led government retreated to the island of Taiwan. The political status of Taiwan remains disputed. Since the introduction of economic reforms in 1978, China's economy has been one of the world's fastest-growing with annual growth rates above 6 percent. According to the World Bank, China's GDP grew from $150 billion in 1978 to $12.24 trillion by 2017. Since 2010, China has been the world's second-largest economy by nominal GDP and since 2014, the largest economy in the world by purchasing power parity.
China is the world's largest exporter and second-largest importer of goods. China is a recognized nuclear weapons state and has the world's largest standing army and second-largest defense budget; the PRC is a permanent member of the United Nations Security Council as it replaced the ROC in 1971, as well as an active global partner of ASEAN Plus mechanism. China is a leading member of numerous formal and informal multilateral organizations, including the Shanghai Cooperation Organization, WTO, APEC, BRICS, the BCIM, the G20. In recent times, scholars have argued that it will soon be a world superpower, rivaling the United States; the word "China" has been used in English since the 16th century. It is not a word used by the Chinese themselves, it has been traced through Portuguese and Persian back to the Sanskrit word Cīna, used in ancient India."China" appears in Richard Eden's 1555 translation of the 1516 journal of the Portuguese explorer Duarte Barbosa. Barbosa's usage was derived from Persian Chīn, in turn derived from Sanskrit Cīna.
Cīna was first used including the Mahābhārata and the Laws of Manu. In 1655, Martino Martini suggested that the word China is derived from the name of the Qin dynasty. Although this derivation is still given in various sources, it is complicated by the fact that the Sanskrit word appears in pre-Qin literature; the word may have referred to a state such as Yelang. The meaning transferred to China as a whole; the origin of the Sanskrit word is still a matter of debate, according to the Oxford English Dictionary. The official name of the modern state is the "People's Republic of China"; the shorter form is "China" Zhōngguó, from zhōng and guó, a term which developed under the Western Zhou dynasty in reference to its royal demesne. It was applied to the area around Luoyi during the Eastern Zhou and to China's Central Plain before being used as an occasional synonym for the state under the Qing, it was used as a cultural concept to distinguish the Huaxia people from perceived "barbarians". The name Zhongguo is translated as "Middle Kingdom" in English.
Archaeological evidence suggests that early hominids inhabited China between 2.24 million and 250,000 years ago. The hominid fossils of Peking Man, a Homo erectus who used fire, were discovered in a cave at Zhoukoudian near Beijing; the fossilized teeth of Homo sapiens have been discovered in Fuyan Cave in Hunan. Chinese proto-writing existed in Jiahu around 7000 BCE, Damaidi around 6000 BCE, Dadiwan from 5800–5400 BCE, Banpo dating from the 5th millennium BCE; some scholars have suggested. According to Chinese tradition, the first dynasty was the Xia, which emerged around 2100 BCE; the dynasty was considered mythical by historians until scientific excavations found early Bronze Age sites at Erlitou, Henan in 1959. It remains unclear whether these sites are the remains of the Xia dynasty or of another culture from the same period; the succeeding Shang dynasty is the earliest to be confirmed by contemporary records. The Shang ruled the plain of the Yellow River in eastern China from the 17th to the 11th century BCE.
Their oracle bone script