- 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, ...
1. The difference between the maximum and minimum of a given set of numbers; in a periodic process it is twice the amplitude, that is, the wave height. 2. The distance between two objects, usually an observation point and an object under observation. See slant range. 3. A maximum distance attributable to some process, as in visual range or the range of an aircraft. 4. The difference between high and low water in a tidal cycle. Ranges greater than 4 m are sometimes termed macrotidal and those less than 2 m are termed microtidal. Intermediate ranges are termed mesotidal. 5. In radar, lidar, and sodar, the radial distance measured outward from the location of the transmitter; ordinarily the distance to a target.
Industry:Weather
1. The characteristic of a system if sufficiently small disturbances have only small effects, either decreasing in amplitude or oscillating periodically; it is asymptotically stable if the effect of small disturbances vanishes for long time periods. A system that is not stable is referred to as unstable, for which small disturbances may lead to large effects. Some authors also distinguish a neutral or marginally stable case, in which disturbances do not vanish, but also do not grow without bound. Classically, stability was defined only with respect to systems in equilibrium. More recently it has been extended to apply to evolving systems, for which an unstable disturbance leads to an evolution that becomes uncorrelated with the undisturbed evolution. From this standpoint stability and predictability can be equated. 2. Same as static stability. 3. The property that each computed solution (in exact arithmetic) of a finite difference approximation remains bounded for all possible choices of the time step. See Lax equivalence theorem. 4. The ability of laminar flow to become turbulent in a fluid.
Industry:Weather
1. The climatic characteristics of the air spaces occupied by plant communities within the canopy. 2. Description of climate characteristics of a region defined largely by distribution of plant species.
Industry:Weather
1. The astronomical condition of alignment of the earth, moon, and sun at new and full moon, the time of maximum spring tidal forcing. At these times the range of tide is greater than average. 2. A west wind on the seas between New Guinea and Australia preceding the summer (northwest) monsoon.
Industry:Weather
1. The areal extent of snow-covered ground, usually expressed as percent of total area in a given region. 2. In general, a layer of snow on the ground surface. Compare snowfield, snowpack. 3. The depth of snow on the ground, usually expressed in inches or centimeters.
Industry:Weather
1. The angular motion of the orbital line of nodes in fixed space; positive to the east, negative to the west. The precession rate for a sun-synchronous orbit is −0. 986° per day, or about 360° per year. The net effect is that the satellite's orbital plane rotates slowly around the earth at the same rate and direction that the earth rotates around the sun, hence, sun-synchronous. 2. The period of time needed for a positional shift in the location of astronomical bodies.
Industry:Weather
1. The apparent surface against which all aerial objects are seen from the earth. 2. Same as sky condition, sky cover, state of the sky.
Industry:Weather
1. That portion of total precipitation used to satisfy vegetation needs. 2. The actual availability of precipitation used in plant development. Availability is affected by such factors as precipitation intensity, season, temperature, ground cover, sod type, etc. The dependence of precipitation effectiveness on temperature and/or evaporation has been expressed in many ways: Köppen's formulas for defining desert climate, Lang's moisture factor, De Martonne's index of aridity, Gorczyński's aridity coefficient, Angström's humidity coefficient, Transeau's precipitation–evaporation quotient, and Thornthwaite's precipitation-effectiveness index.
Industry:Weather
1. The amount of water evaporated (both as transpiration and evaporation from the soil) from an area of continuous, uniform vegetation that covers the whole ground and that is well supplied with water. Generally, the amount of moisture that, if available, would be removed from a given land area by evapotranspiration; expressed in units of water depth. It can be measured in a dry basin by determining the amount of irrigation water used, and in wetter regions, by the difference between rainfall and runoff, or by the supply of water required to maintain a constant amount of soil moisture in an isolated block of the soil. See evapotranspirometer. 2. The quantity of water evaporated (both as transpiration and evaporation from the soil) per unit area, per unit time from an extensive stretch of continuous, uniform vegetation that covers the whole ground and that is well supplied with water. ; an empirical index of the above. As given in Thornthwaite's 1948 climatic classification, it is equal to the summation of the 12 successive monthly values of the expression ''ct<sup>a</sup>'', where ''t'' is the monthly mean temperature in degrees Celsius, and ''a'' and ''c'' are coefficients that depend upon the annual heat index.
Industry:Weather
1. The amount by which the water vapor in the air must be increased to achieve saturation without changing the environmental temperature and pressure. The saturation deficit may be expressed in terms of a vapor pressure deficit, an absolute humidity deficit, or a relative humidity deficit. 2. The physiological saturation deficit: “The difference between the amount of vapor actually present in the air (i.e., the absolute humidity) and amount that saturated air at body temperature contains (viz. , about 45 gm per cubic m). ”
Industry:Weather
