Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through the material without being scattered. On a macroscopic scale, the photons can be said to follow Snell's Law. Translucency is a superset of transparency: it allows light to pass through, but does not follow Snell's law. In other words, a translucent medium allows the transport of light while a transparent medium not only allows the transport of light but allows for image formation. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color; the opposite property of translucency is opacity. When light encounters a material, it can interact with it in several different ways; these interactions depend on the nature of the material. Photons interact with an object by some combination of reflection and transmission; some materials, such as plate glass and clean water, transmit much of the light that falls on them and reflect little of it.
Many liquids and aqueous solutions are transparent. Absence of structural defects and molecular structure of most liquids are responsible for excellent optical transmission. Materials which do not transmit light are called opaque. Many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of white light frequencies, they absorb certain portions of the visible spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation; this is. The attenuation of light of all frequencies and wavelengths is due to the combined mechanisms of absorption and scattering. Transparency can provide perfect camouflage for animals able to achieve it; this is easier in turbid seawater than in good illumination. Many marine animals such as jellyfish are transparent. With regard to the absorption of light, primary material considerations include: At the electronic level, absorption in the ultraviolet and visible portions of the spectrum depends on whether the electron orbitals are spaced such that they can absorb a quantum of light of a specific frequency, does not violate selection rules.
For example, in most glasses, electrons have no available energy levels above them in range of that associated with visible light, or if they do, they violate selection rules, meaning there is no appreciable absorption in pure glasses, making them ideal transparent materials for windows in buildings. At the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, on selection rules. Nitrogen and oxygen are not greenhouse gases because there is no absorption, but because there is no molecular dipole moment. With regard to the scattering of light, the most critical factor is the length scale of any or all of these structural features relative to the wavelength of the light being scattered. Primary material considerations include: Crystalline structure: whether or not the atoms or molecules exhibit the'long-range order' evidenced in crystalline solids. Glassy structure: scattering centers include fluctuations in density or composition.
Microstructure: scattering centers include internal surfaces such as grain boundaries, crystallographic defects and microscopic pores. Organic materials: scattering centers include fiber and cell structures and boundaries. Diffuse reflection - Generally, when light strikes the surface of a solid material, it bounces off in all directions due to multiple reflections by the microscopic irregularities inside the material, by its surface, if it is rough. Diffuse reflection is characterized by omni-directional reflection angles. Most of the objects visible to the naked eye are identified via diffuse reflection. Another term used for this type of reflection is "light scattering". Light scattering from the surfaces of objects is our primary mechanism of physical observation. Light scattering in liquids and solids depends on the wavelength of the light being scattered. Limits to spatial scales of visibility therefore arise, depending on the frequency of the light wave and the physical dimension of the scattering center.
Visible light has a wavelength scale on the order of a half a micrometer. Scattering centers as small. Optical transparency in polycrystalline materials is limited by the amount of light, scattered by their microstructural features. Light scattering depends on the wavelength of the light. Limits to spatial scales of visibility therefore arise, depending on the frequency of the light wave and the physical dimension of the scattering center. For example, since visible light has a wavelength scale on the order of a micrometer, scattering centers will have dimensions on a similar spatial scale. Primary scattering centers in polycrystalline materi
Hard and soft light
Hard and soft light are different types of lighting that are used in photography and filmmaking. Soft light refers to light that tends to "wrap" around objects, casting diffuse shadows with soft edges. Soft light is; the hardness or softness of light depends on the following two factors: Distance. The closer the light source, the softer it becomes. Size of light source; the larger the source, the softer it becomes. The softness of a light source can be determined by the angle between the illuminated object and the'length' of the light source; the larger this angle is, the softer the light source. Soft light use is popular in cinematography and film for a number of different reasons: Cast shadow-less light. Fill lighting. Soft light can reduce shadows without creating additional shadows. Make a subject appear more beautiful or youthful through making wrinkles less visible. Supplement the lighting from practicals; this technique is used to perform "motivated" lighting, where all light in the scene appears to come from practical light sources in the scene.
Soft light does not cast shadows. Hard light sources cast shadows. For example, fresnel lights can be focused such; that is, the shadows produced will have'harder' edges with less transition between illumination and shadow. The focused light will produce harder-edged shadows. Focusing a fresnel makes the rays of emitted light more parallel; the parallelism of these rays determines the quality of the shadows. For shadows with no transitional edge/gradient, a point light source is required. Hard light casts strong; when hitting a textured surface at an angle, hard light will accentuate the textures and details in an object. Light intensity tends to dim with distance. For a point source of light, intensity decreases as distance increases. Intensity is inversely proportional to the square of the distance, as expressed in the formula I = 1⁄D2. For a thin infinitely long light source, intensity is inversely proportional to distance. For a light source of infinite area, intensity does not decrease at all.
A soft light source does not drop in intensity as as a point light source would. Certain lensed lighting instruments have a good deal of "throw" and do not lose much intensity as distance increases; these light sources tend to be more effective at large distances than soft light sources. At large distances, an effective soft light source would have to be large; the parallel rays of such instruments tends to cast hard shadows, unlike soft light sources. Most light sources have a non-negligible size and therefore exhibit the properties of a soft light to some degree; the sun does not cast hard shadows. In "hard" light sources, the parallelism of the rays is an important factor in determining shadow behaviour; the quality of light can be altered by using diffusion gel or aiming a lighting instrument at diffusing material such as a silk. When shooting outdoors, cloud cover provides nature's version of a softbox. Ellipsoidal reflector spotlight Beauty Dish http://www.shortcourses.com/tabletop/lighting2-8.html
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century; the 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data, it was not until after the elucidation of the laws of physics and more the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by the science of meteorology.
Meteorological phenomena are described and quantified by the variables of Earth's atmosphere: temperature, air pressure, water vapour, mass flow, the variations and interactions of those variables, how they change over time. Different spatial scales are used to describe and predict weather on local and global levels. Meteorology, atmospheric physics, atmospheric chemistry are sub-disciplines of the atmospheric sciences. Meteorology and hydrology compose the interdisciplinary field of hydrometeorology; the interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport and construction; the word meteorology is from the Ancient Greek μετέωρος metéōros and -λογία -logia, meaning "the study of things high in the air". The ability to predict rains and floods based on annual cycles was evidently used by humans at least from the time of agricultural settlement if not earlier.
Early approaches to predicting weather were practiced by priests. Cuneiform inscriptions on Babylonian tablets included associations between rain; the Chaldeans differentiated 46 ° halos. Ancient Indian Upanishads contain mentions of seasons; the Samaveda mentions sacrifices to be performed. Varāhamihira's classical work Brihatsamhita, written about 500 AD, provides evidence of weather observation. In 350 BC, Aristotle wrote Meteorology. Aristotle is considered the founder of meteorology. One of the most impressive achievements described in the Meteorology is the description of what is now known as the hydrologic cycle; the book De Mundo noted If the flashing body is set on fire and rushes violently to the Earth it is called a thunderbolt. They are all called ` swooping bolts'. Lightning is sometimes smoky, is called'smoldering lightning". At other times, it travels in crooked lines, is called forked lightning; when it swoops down upon some object it is called'swooping lightning'. The Greek scientist Theophrastus compiled a book on weather forecasting, called the Book of Signs.
The work of Theophrastus remained a dominant influence in the study of weather and in weather forecasting for nearly 2,000 years. In 25 AD, Pomponius Mela, a geographer for the Roman Empire, formalized the climatic zone system. According to Toufic Fahd, around the 9th century, Al-Dinawari wrote the Kitab al-Nabat, in which he deals with the application of meteorology to agriculture during the Muslim Agricultural Revolution, he describes the meteorological character of the sky, the planets and constellations, the sun and moon, the lunar phases indicating seasons and rain, the anwa, atmospheric phenomena such as winds, lightning, floods, rivers, lakes. Early attempts at predicting weather were related to prophecy and divining, were sometimes based on astrological ideas. Admiral FitzRoy tried to separate scientific approaches from prophetic ones. Ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. In 1021, Alhazen showed that atmospheric refraction is responsible for twilight.
St. Albert the Great was the first to propose that each drop of falling rain had the form of a small sphere, that this form meant that the rainbow was produced by light interacting with each raindrop. Roger Bacon was the first to calculate the angular size of the rainbow, he stated. In the late 13th century and early 14th century, Kamāl al-Dīn al-Fārisī and Theodoric of Freiberg were the first to give the correct explanations for the primary rainbow phenomenon. Theoderic went further and explained the secondary rainbow. In 1716, Edmund Halley suggested that aurorae are caused by "magnetic effluvia" moving along the Earth's magnetic field lines. In 1441, King Sejong's son, Prince Munjong of Korea, invented the first standardized rain gauge; these were sent throughout the Joseon dynasty of Korea as an official tool to assess land taxes based
World Meteorological Organization
The World Meteorological Organization is an intergovernmental organization with a membership of 192 Member States and Territories. Its current Secretary-General is Petteri Taalas and the President of the World Meteorological Congress, its supreme body, is David Grimes; the Organization is headquartered in Switzerland. It followed on from the International Meteorological Organization, founded in 1873, a non-governmental organization. Reforms of status and structure were proposed from the 1930s, culminating in the World Meteorological Convention signed on 11 October 1947 which came into force on 23 March 1950, it formally became the World Meteorological Organization on 17 March 1951, was designated as a specialized agency of the United Nations. WMO has a membership of 191 Member States and Territories as of February 2014; the Convention of the World Meteorological Organization was signed 11 October 1947 and established upon ratification on 23 March 1950. The WMO hierarchy: The World Meteorological Congress, the supreme body of the Organization, determines policy.
Each member state and territory is represented by a Permanent Representative with WMO when Congress meets every four years. Congress elects the President and Vice-Presidents of the Organization and members of the Executive Council; the Executive Council implements Congress decisions. The Secretariat is an eight-department organization with a staff of 200 headed by a Secretary-General, who can serve a maximum of two four-year terms; the annually published WMO Statements on the status of the World Climate provides details of global and national temperatures and extreme weather events. It provides information on long-term climate change indicators including atmospheric concentrations of greenhouse gases, sea level rise, sea ice extent; the year 2016 was the hottest year on record, with many weather and climate extremes, according to the most recent WMO report. Disaster risk reduction The Global Framework for Climate Services The WMO Integrated Global Observing System Aviation meteorological services Polar and high mountain regions Capacity development Governance In keeping with its mandate to promote the standardization of meteorological observations, the WMO maintains numerous code forms for the representation and exchange of meteorological and hydrological data.
The traditional code forms, such as SYNOP, CLIMAT and TEMP, are character-based and their coding is position-based. Newer WMO code forms are designed for portability and universality; these are BUFR, CREX, for gridded geo-positioned data, GRIB. The WMO and United Nations Environment Programme jointly created Intergovernmental Panel on Climate Change received the Nobel Peace Prize in 2007 "for their efforts to build up and disseminate greater knowledge about anthropogenic climate change, to lay the foundations for the measures that are needed to counteract such change." World Meteorological Day is held annually on 23 March. The World Meteorological Organization at a Glance WMO Public website WMO for Youth WMO Bulletin WMO Greenhouse Gas Bulletin WMO Statements on the Status of the World Climate International Meteorological Organization Prize Professor Dr Vilho Väisälä Awards Norbert Gerbier-Mumm International Award WMO Research Award for Young Scientists Professor Mariolopoulus Award As of March 2019, WMO Members include a total of 186 Member States and 6 Member Territories.
Ten United Nations member states are not members of WMO: Equatorial Guinea, Liechtenstein, Marshall Islands, Palau, Saint Kitts and Nevis, Saint Vincent and the Grenadines and San Marino. Cook Islands and Niue are WMO non-members of the United Nations. Vatican City and State of Palestine and the states with limited recognition are not members of either organization; the six WMO Member Territories are the British Caribbean Territories, French Polynesia, Hong Kong, Curaçao and Sint Maarten and New Caledonia. Region I consists of the states of a few former colonial powers. Region I has 57 member states and no member territories: Non-member Equatorial Guinea Region II has 33 member states and 2 member territories; the member states are: The member territories are: Hong Kong - China Macau - China Region III consists of the states of South America, including France as French Guiana is an overseas region of France. It has a total of 13 member states and no member territories: Region IV consists of the states of North America, Central America, the Caribbean, including three European states with dependencies within the region.
It has a total of 2 member territories. The member states are: Region V consists of 21 member states and 2 member territories; the member states are: Region VI consists consist of all the states in Europe as well as some Western Asia. It has 50 member states: A total of ten member states have membership in more than one region. Two nations are members to four different regions; these nations, with their regions, are as follows: Aircraft Meteorological Data Relay Cloud atlas Global Atmospheric Research Program International Cloud Atlas Regional Specialized Meteorological Center "Public website". WMO. Official website "International List of Selected and Auxiliary Ships". International Comprehensive Ocean-Atmosphere Data Set. 1999. Pub 47. In
Mehamn is the administrative centre of Gamvik Municipality in Finnmark county, Norway. The village is located on the small Vedvik peninsula, itself part of the greater Nordkinn Peninsula, at the southern end of the Mehamnfjorden, a bay off of the Barents Sea; the village of Gamvik lies about 16 kilometres to the east and the village of Kjøllefjord lies about 30 kilometres to the southwest. Mehamn Chapel is located in this village; the 0.52-square-kilometre village has a population of 779 which gives the village a population density of 1,498 inhabitants per square kilometre. Norwegian County Road 888 connects Mehamn to the European route E06 highway at the base of the Nordkinn Peninsula, from there on to the towns of Kirkenes in the east and Alta in the west. Mehamn is a port of call for the Hurtigruten coastal ship. Mehamn is connected by air via Mehamn Airport, with services by Widerøe to the nearby city of Tromsø. Svend Foyn established the whaling station in Mehamn, built in 1884-1885, it was put into use starting in the spring of 1885, it became the largest of its kind in Finnmark county.
After Foyn’s death in 1894, the whaling station was run by Foyn’s whaling company. Svend Foyn established the Svend Foyn Chapel, in Mehamn starting in 1887; the background for the Mehamn rebellion was a period of miserable capelin fishing. The fishermen blamed the local whaling, they believed. With few whales left, the fish stayed out of reach. Frustrations were growing by the day during spring of 1903. By Whitsunday, about 2000 angry fishermen were in harbour in Mehamn. At the time, the village had 123 permanent residents; when the new manager of the whaling station denied help to a fishing boat that came from sea with a broken helm, the fishermen had had enough. On the 2nd of June 1903, a large number of them gathered outside the factory. During the following two days, machinery was destroyed, chimneys were torn down, the large steam boilers were sunk; the guard and the single police officer watch. Military forces from Vardø and Harstad were mobilized, but did not reach Mehamn before the factory was destroyed and the situation was calm again.
Some of the vandals were convicted. They received light sentences in jail and the following autumn, general elections were held, the Labour Party, which had fought for the protection of the whales, entered parliament for the first time with four MPs, they all represented the three northernmost counties of Norway. They were said to have “ridden to Parliament on a whale’s back.” In December, a law was passed ensuring the preservation of the whales in Norwegian waters off the coast of Nordland and Finnmark. On 11 March 1982, a Widerøe Twin Otter crashed into the sea on approach to Mehamn Airport during flight from Berlevåg Airport, killing all on board. Despite controversies regarding the cause of the crash, clear-air turbulence over the Mehamnfjorden was determined as the official cause
Climatology or climate science is the scientific study of climate, scientifically defined as weather conditions averaged over a period of time. This modern field of study is regarded as a branch of the atmospheric sciences and a subfield of physical geography, one of the Earth sciences. Climatology now includes aspects of biogeochemistry. Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño–Southern Oscillation, the Madden–Julian oscillation, the North Atlantic oscillation, the Northern Annular Mode, known as the Arctic oscillation, the Northern Pacific Index, the Pacific decadal oscillation, the Interdecadal Pacific Oscillation. Climate models are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate. Weather is known as the condition of the atmosphere over a period of time, while climate has to do with the atmospheric condition over an extended to indefinite period of time.
Chinese scientist Shen Kuo inferred that climates shifted over an enormous span of time, after observing petrified bamboos found underground near Yanzhou, a dry-climate area unsuitable for the growth of bamboo. Early climate researchers include Edmund Halley, who published a map of the trade winds in 1686 after a voyage to the southern hemisphere. Benjamin Franklin first mapped the course of the Gulf Stream for use in sending mail from the United States to Europe. Francis Galton invented the term anticyclone. Helmut Landsberg fostered the use of statistical analysis in climatology, which led to its evolution into a physical science; the Greeks began the formal study of climate. The first distinct climate treaties were the works of Hippocrates, who wrote Airs and Places in 400 B. C. E. Climatology is approached in various ways such as Paleoclimatology, which seeks to reconstruct past climates by examining records such as ice cores and tree rings. Paleotempestology uses these same records to help determine hurricane frequency over millennia.
The study of contemporary climates incorporates meteorological data accumulated over many years, such as records of rainfall and atmospheric composition. Knowledge of the atmosphere and its dynamics is embodied in models, either statistical or mathematical, which help by integrating different observations and testing how they fit together. Modeling is used for understanding past and potential future climates. Historical climatology is the study of climate as related to human history and thus focuses only on the last few thousand years. Climate research is made difficult by the large scale, long time periods, complex processes which govern climate. Climate is governed by physical laws; these equations are coupled and nonlinear, so that approximate solutions are obtained by using numerical methods to create global climate models. Climate is sometimes modeled as a stochastic process but this is accepted as an approximation to processes that are otherwise too complicated to analyze. Scientists use climate indices based on several climate patterns in their attempt to characterize and understand the various climate mechanisms that culminate in our daily weather.
Much in the way the Dow Jones Industrial Average, based on the stock prices of 30 companies, is used to represent the fluctuations in the stock market as a whole, climate indices are used to represent the essential elements of climate. Climate indices are devised with the twin objectives of simplicity and completeness, each index represents the status and timing of the climate factor it represents. By their nature, indices are simple, combine many details into a generalized, overall description of the atmosphere or ocean which can be used to characterize the factors which impact the global climate system. El Niño–Southern Oscillation is a global coupled ocean-atmosphere phenomenon; the Pacific Ocean signatures, El Niño and La Niña are important temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. The name El Niño, from the Spanish for "the little boy", refers to the Christ child, because the phenomenon is noticed around Christmas time in the Pacific Ocean off the west coast of South America.
La Niña means "the little girl". Their effect on climate in the subtropics and the tropics are profound; the atmospheric signature, the Southern Oscillation reflects the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin. The most recent occurrence of El Niño started in September 2006 and lasted until early 2007. ENSO is a set of interacting parts of a single global system of coupled ocean-atmosphere climate fluctuations that come about as a consequence of oceanic and atmospheric circulation. ENSO is the most prominent known source of inter-annual variability in weather and climate around the world; the cycle occurs every two to seven years, with El Niño lasting nine months to two years within the longer term cycle, though not all areas globally are affected. ENSO has signatures in the Pacific and Indian Oceans. In the Pacific, during major warm events, El Niño warming extends over much of the tropical Pacific and becomes linked to the SO intensity. While ENSO events are in phase between the Pacific and Indian Ocean
Cloud cover refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of measurement of the cloud cover; the cloud cover is correlated to the sunshine duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This value is lower when considering clouds with an optical depth larger than 2, higher when counting subvisible cirrus clouds. Clouds play multiple critical roles in the climate system. In particular, being bright objects in the visible part of the solar spectrum, they efficiently reflect light to space and thus contribute to the cooling of the planet. Cloud cover thus plays an important role in the energetic balance of the atmosphere and a variation of it is a consequence of and to the climate change expected by recent studies. Cloud cover values only vary by 0.03 from year to year, whereas the local, day to day variability in cloud amount rises to 0.3 over the globe.
Most data sets agree on the fact. Lastly, there is a latitudinal variation in the cloud cover, such that around 20°N there are regions with 0.10 less cloudiness than the global mean. The same variation is found 20°S. On the other hand, in the storm regions of the Southern Hemisphere midlatitudes were found to have with 0.15-0.25 more cloudiness than the global mean at 60°S. On average, about 52% of Earth is cloud-covered at any moment; some regions are always cloudy such as the Amazon Rainforest and some others are always clear such as the Sahara Desert. McIntosh, D. H. Meteorological Glossary, Her Majesty's Stationery Office, Met. O. 842, A. P. 897, 319 p. NSDL.arm.gov, Glossary of Atmospheric Terms, From the National Science Digital Library's Atmospheric Visualization Collection. Earthobersvatory.nasa.gov, Monthly maps of global cloud cover from NASA's Earth Observatory International Satellite Cloud Climatology Project, NASA's data products on their satellite observations NASA composite satellite image