- 行业: Weather
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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, ...
A type of one-and-a-half-order turbulence closure that retains forecast equations for mean (first-order statistics) variables such as potential temperature and wind components, and also retains equations for variances (turbulence kinetic energy and temperature variance, symbolized by k) and for molecular dissipation or destruction of variances (symbolized by ε). Compare first-order closure, K-theory, second-order closure, nonlocal closure, Reynolds averaging, closure assumptions.
Industry:Weather
A type of evaporation gauge that consists of a tank or pan of soil placed in a field and manipulated so that the soil, water, thermal, and vegetative properties in the tank duplicate as closely as possible the properties of the surrounding area. Relatively sophisticated lysimeters use various methods to determine the reductions in weight of the instruments so that water loss due to evapotranspiration can be computed. In some cases, the water table level in the lysimeter is adjusted to coincide with a high water table outside the tank. Lysimeters are used for several other purposes. In a potential evapotranspirometer, the water table in the tank is held sufficiently high so that vegetative evapotranspiration is not limited by soil moisture stress. Some types of lysimeters are devoted to studies of chemical leaching by water or to the fate of nutrients or potentially toxic substances, for which water is removed from near the bottom of the tank for chemical analysis. Shear-stress lysimeters have been developed to measure the surface momentum flux from the atmosphere by use of strain gauges or displacement meters attached to the tank.
Industry:Weather
A type of conformal map in which features on a sphere are projected onto a cone. The cone can either be tangent to the sphere, for which contact is along one circle, or pass through the sphere, for which contact is along two circles.
Industry:Weather
A type of cooling-power anemometer based upon the principle that the time constant of a thermometer is a function of its ventilation. The form developed in the early nineteenth century consisted of a liquid-in-glass thermometer having two calibration markers on the stem corresponding to 38. 5° and 35°C. The thermometer was heated to 40°C, and the time required for the column to fall from 38° to 35°C was measured by a stopwatch and used to compute the wind speed. It was especially useful for very low wind speeds. The katathermometer was used also, in human bioclimatology, to determine cooling power.
Industry:Weather
A thin and more or less patchy deposit of hoarfrost on surface objects and vegetation. This term is used, inappropriately, for a light freeze.
Industry:Weather
A trace organic impurity in water with a polar or similar chemical group that disperses the material as a surface near monomolecular layer and influences surface properties as water vapor deposition coefficient, vapor pressure, and surface tension.
Industry:Weather
A type of cistern barometer. No adjustment is made for the variation of the level of the mercury in the cistern as pressure changes occur; rather, a uniformly contracting scale is used to determine the effective height of the mercury column.
Industry:Weather
A thermometer in which the thermally sensitive element is a liquid contained in a metal envelope, frequently in the form of a Bourdon tube. Otherwise, the indicator portion may be liquid-in-glass.
Industry:Weather
A thermal belt, either of latitude or altitude, in which the plant and animal life is of a distinctive type. The limits of each life zone are mainly fixed by minimum temperatures. The major life zones are boreal, temperate, subtropical, and tropical in both Northern and Southern Hemispheres, with tropical being equatorial. Within each thermal life zone, moisture gradients provide further subdivisions into a number of biogeographical provinces. Latitudinal and altitudinal life zones are not strictly equivalent.
Industry:Weather
A thermometer in which the thermally sensitive element is a liquid contained in a graduated glass envelope. The indication of such a thermometer depends upon the difference between the coefficients of thermal expansion of the liquid and the glass. Mercury and alcohol are liquids commonly used in meteorological thermometers. See spirit thermometer.
Industry:Weather
