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Wind Gradient
In common usage, wind gradient, more specifically wind speed gradient or wind velocity gradient, or alternatively shear wind, is the vertical component of the gradient of the mean horizontal wind speed in the lower atmosphere. It is the rate of increase of wind strength with unit increase in height above ground level. In metric units, it is often measured in units of meters per second of speed, per kilometer of height (m/s/km), which reduces inverse milliseconds (ms−1), a unit also used for shear rate. Simple explanation Surface friction forces the surface wind to slow and turn near the surface of the Earth, blowing directly towards the low pressure, when compared to the winds in the nearly frictionless flow well above the Earth's surface. This bottom layer, where surface friction slows the wind and changes the wind direction, is known as the planetary boundary layer. Daytime solar heating due to insolation thickens the boundary layer, as air warmed by contact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Institute Of Aeronautics And Astronautics
The American Institute of Aeronautics and Astronautics (AIAA) is a professional society for the field of aerospace engineering Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is s .... The AIAA is the U.S. representative on the International Astronautical Federation and the International Council of the Aeronautical Sciences. In 2015, it had more than 30,000 members among aerospace professionals worldwide (a majority are American or live in the United States). History The AIAA was founded in 1963 from the merger of two earlier societies: the American Rocket Society (ARS), founded in 1930 as the American Interplanetary Society (AIS), and the Institute of the Aerospace Sciences (IAS), founded in 1932 as the Institute of the Aeronautical Sciences. Paul Johnston was the first executive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollutants
A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effect, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oil) or anthropogenic in origin (i.e. manufactured materials or byproducts). Pollutants result in environmental pollution or become of public health concern when they reach a concentration high enough to have significant negative impacts. A pollutant may cause long- or short-term damage by changing the growth rate of plant or animal species, or by interfering with resources used by humans, human health or wellbeing, or property values. Some pollutants are biodegradable and therefore will not persist in the environment in a long term. However, the degradation products of some pollutants are themselves pollutants such as DDE and DDD produced from the degradation of DDT. Pollution has widespread negative impact on the environment. When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiative Cooling
In the study of heat transfer, radiative cooling is the process by which a body loses heat by thermal radiation. As Planck's law describes, every physical body spontaneously and continuously emits electromagnetic radiation. Radiative cooling has been applied in various contexts throughout human history, including Ice-making, ice making in India and Iran, Heat shield, heat shields for spacecraft, and in architecture. In 2014, a scientific breakthrough in the use of Photonic metamaterial, photonic metamaterials made daytime radiative cooling possible. It has since been proposed as a strategy to mitigate local and global warming caused by greenhouse gas emissions known as passive daytime radiative cooling. Terrestrial radiative cooling Mechanism Infrared radiation can pass through dry, clear air in the wavelength range of 8–13 μm. Materials that can absorb energy and radiate it in those wavelengths exhibit a strong cooling effect. Materials that can also reflect 95% or mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Applied Meteorology And Climatology
The ''Journal of Applied Meteorology and Climatology'' (JAMC; formerly ''Journal of Applied Meteorology'') is a scientific journal published by the American Meteorological Society. Applied research related to the physical meteorology, cloud physics, hydrology, weather modification, satellite meteorology, boundary layer processes, air pollution meteorology (including dispersion and chemical processes), agricultural and forest meteorology, and applied meteorological numerical models of all types. See also * List of scientific journals ** List of scientific journals in earth and atmospheric sciences This list presents notable scientific journals in earth and atmospheric sciences and its various subfields. Multi-disciplinary Atmospheric science Geochemistry * ''Chemical Geology'' * '' Geochimica et Cosmochimica Acta'' * '' Geostan ... Atmospheric dispersion modeling Academic journals established in 1962 English-language journals American Meteorological Society a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ekman Spiral
Ekman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman transport is a component of wind-driven ocean current. Ekman transport occurs when ocean surface waters are influenced by the friction force acting on them via the wind. As the wind blows it casts a friction force on the ocean surface that drags the upper 10-100m of the water column with it. However, due to the influence of the Coriolis effect, as the ocean water moves it is subject to a force at a 90° angle from the direction of motion causing the water to move at an angle to the wind direction. The direction of transport is dependent on the hemisphere: in the northern hemisphere, transport veers clockwise from wind direction, while in the southern hemisphere it veers anticlockwise.Colling, pp 42-44 This phenomenon was first noted by Fridtjof Nansen, who recorded that ice transport appeared to occur at an angle to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shearing (physics)
In continuum mechanics, shearing refers to the occurrence of a shear strain, which is a deformation of a material substance in which parallel internal surfaces slide past one another. It is induced by a shear stress in the material. Shear strain is distinguished from volumetric strain. The change in a material's volume in response to stress and change of angle is called the angle of shear. Overview Often, the verb ''shearing'' refers more specifically to a mechanical process that causes a plastic shear strain in a material, rather than causing a merely elastic one. A plastic shear strain is a continuous (non-fracturing) deformation that is irreversible, such that the material does not recover its original shape. It occurs when the material is yielding. The process of shearing a material may induce a volumetric strain along with the shear strain. In soil mechanics, the volumetric strain associated with shearing is known as Reynolds' dilation if it increases the volume, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Applied Meteorology
The ''Journal of Applied Meteorology and Climatology'' (JAMC; formerly ''Journal of Applied Meteorology'') is a scientific journal published by the American Meteorological Society. Applied research related to the physical meteorology, cloud physics, hydrology, weather modification, satellite meteorology, boundary layer processes, air pollution meteorology (including dispersion and chemical processes), agricultural and forest meteorology, and applied meteorological numerical models of all types. See also * List of scientific journals ** List of scientific journals in earth and atmospheric sciences This list presents notable scientific journals in earth and atmospheric sciences and its various subfields. Multi-disciplinary Atmospheric science Geochemistry * ''Chemical Geology'' * '' Geochimica et Cosmochimica Acta'' * '' Geostan ... Atmospheric dispersion modeling Academic journals established in 1962 English-language journals American Meteorological Society a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logarithm
In mathematics, the logarithm of a number is the exponent by which another fixed value, the base, must be raised to produce that number. For example, the logarithm of to base is , because is to the rd power: . More generally, if , then is the logarithm of to base , written , so . As a single-variable function, the logarithm to base is the inverse of exponentiation with base . The logarithm base is called the ''decimal'' or ''common'' logarithm and is commonly used in science and engineering. The ''natural'' logarithm has the number as its base; its use is widespread in mathematics and physics because of its very simple derivative. The ''binary'' logarithm uses base and is widely used in computer science, information theory, music theory, and photography. When the base is unambiguous from the context or irrelevant it is often omitted, and the logarithm is written . Logarithms were introduced by John Napier in 1614 as a means of simplifying calculation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exponent
In mathematics, exponentiation, denoted , is an operation involving two numbers: the ''base'', , and the ''exponent'' or ''power'', . When is a positive integer, exponentiation corresponds to repeated multiplication of the base: that is, is the product of multiplying bases: b^n = \underbrace_.In particular, b^1=b. The exponent is usually shown as a superscript to the right of the base as or in computer code as b^n. This binary operation is often read as " to the power "; it may also be referred to as " raised to the th power", "the th power of ", or, most briefly, " to the ". The above definition of b^n immediately implies several properties, in particular the multiplication rule:There are three common notations for multiplication: x\times y is most commonly used for explicit numbers and at a very elementary level; xy is most common when variables are used; x\cdot y is used for emphasizing that one talks of multiplication or when omitting the multiplication sign would ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Law
In statistics, a power law is a Function (mathematics), functional relationship between two quantities, where a Relative change and difference, relative change in one quantity results in a relative change in the other quantity proportional to the change raised to a constant exponent: one quantity varies as a power of another. The change is independent of the initial size of those quantities. For instance, the area of a square has a power law relationship with the length of its side, since if the length is doubled, the area is multiplied by 2, while if the length is tripled, the area is multiplied by 3, and so on. Empirical examples The distributions of a wide variety of physical, biological, and human-made phenomena approximately follow a power law over a wide range of magnitudes: these include the sizes of craters on the moon and of solar flares, cloud sizes, the foraging pattern of various species, the sizes of activity patterns of neuronal populations, the frequencies of words ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Shear
Simple shear is a deformation in which parallel planes in a material remain parallel and maintain a constant distance, while translating relative to each other. In fluid mechanics In fluid mechanics, simple shear is a special case of deformation where only one component of velocity vectors has a non-zero value: :V_x=f(x,y) :V_y=V_z=0 And the gradient of velocity is constant and perpendicular to the velocity itself: :\frac = \dot \gamma , where \dot \gamma is the shear rate and: :\frac = \frac = 0 The displacement gradient tensor Γ for this deformation has only one nonzero term: :\Gamma = \begin 0 & & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end Simple shear with the rate \dot \gamma is the combination of pure shear strain with the rate of \dot \gamma and rotation with the rate of \dot \gamma: :\Gamma = \begin \underbrace \begin 0 & & 0 \\ 0 & 0 & 0 \\ 0 & 0 & 0 \end \\ \mbox\end = \begin \underbrace \begin 0 & & 0 \\ & 0 & 0 \\ 0 & 0 & 0 \end \\ \mbox \end + \b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
