- Industry: Weather
- Number of terms: 60695
- Number of blossaries: 0
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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
The blockage of ocean surface waves in an opposing current. Blocking occurs when the phase speed of a wave equals the magnitude of the opposing current speed.
Industry:Weather
The body of principles and techniques concerned with measuring atmospheric extinction using various types of telephotometer. See photometry, radiometer.
Industry:Weather
The boundary between the troposphere and stratosphere, usually characterized by an abrupt change of lapse rate. The change is in the direction of increased atmospheric stability from regions below to regions above the tropopause. Its height varies from 15 to 20 km (9 to 12 miles) in the Tropics to about 10 km (6 miles) in polar regions. In polar regions in winter it is often difficult or impossible to determine just where the tropopause lies, since under some conditions there is no abrupt change in lapse rate at any height. It has become apparent that the tropopause consists of several discrete, overlapping “leaves,” a multiple tropopause, rather than a single continuous surface. In general, the leaves descend, step-wise, from the equator to the poles.
Industry:Weather
The change in the radiative effect of water vapor in response to an external perturbation of the climate. Water vapor, the most important greenhouse gas, absorbs only a small amount of sunlight but is a very efficient absorber of the earth's thermal infrared emission. Changes in either the amount or the vertical distribution of water vapor can therefore change the planet's ability to radiate heat to space. Climate models predict, without exception, that the water vapor feedback is positive. Changes in the distribution of water vapor in the middle and upper troposphere are inordinately important to this feedback process, because molecules that absorb upwelling infrared radiation at these altitudes emit it to space at a much colder temperature and therefore emit less than would be the case in their absence. The concentration of high-altitude water vapor is controlled by poorly understood dynamic and thermodynamic processes and is inadequately observed, thus contributing to uncertainty in the magnitude of the water vapor feedback.
Industry:Weather
The change in wave propagation as affected by the presence of obstacles (e.g., sea walls or islands). As the waves pass the obstacle the wave crests bend as the wave moves into the shadow of the obstacle.
Industry:Weather
The characteristic geometry formed by a city street and its flanking buildings. Together with the intervening roofs they provide a first-order repetitive structure to cities with characteristic patterns of sunlight and shade and cross-street vortices. Commonly described by their nondimensional aspect ratio ''H''/''W'', where ''H'' is the mean height of the buildings and ''W'' the width of the street.
Industry:Weather
The climate affected by the presence of a town or city. Urban development greatly modifies the radiative, thermal, moisture, and aerodynamic properties of the surface. This change alters the fluxes and balances of heat, mass, and momentum, producing a distinct urban boundary layer.
Industry:Weather
The closed surface or tube consisting of the vortex lines passing through every point of a given closed curve.
Industry:Weather
The closing of the stomata by a plant in response to excessive water loss through transpiration or in response to drought conditions.
Industry:Weather
The cloud of particles injected into the stratosphere by explosive volcanic eruptions. The particles consist mainly of sulfuric acid droplets, and their influence on incoming solar radiation gives rise to cooling at the earth's surface during major events. The effects can persist for years.
Industry:Weather
