- 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, ...
For any threshold, x, the probability that during the year the random variable in question, X, will exceed some x; exceedance probability =.
Industry:Weather
The average number of years between the occurrence of an event and that of a “greater” event.
Industry:Weather
1. (circa 1960) A device that uses eddy correlation to measure the turbulent vertical flux density of water vapor within a few meters of the surface of the earth. Evapotrons were originally designed with analog electronics to make the necessary covariance calculations in real time. This term is not in common use for systems that make the covariance calculations with modern digital electronics.
2. (circa 2010) A device employed in ecologically sensitive arid environments to dispose of contaminated water by evaporation. Such devices were invented in response to the "Leave No Trace" obligation for camps at the Burning Man art festival to dispose of wastewater responsibly. The predominant designs are the "Gray-B-Gon", which is wind-powered, and the "Pumped Cascade", which is powered by an electricity source driving a small pump. See www.evapotrons.info for evapotron history, design varieties, and construction guidance.
Industry:Weather
A type of lysimeter that measures the rate of evapotranspiration. It consists of a vegetation soil tank so designed that all water added to the tank and all water left after evapotranspiration can be measured, usually by weighing.
Industry:Weather
A class of evaporation gauges, which includes evaporation pans and atmometers, that measure evaporation from free-standing water or a thoroughly wetted surface.
Industry:Weather
Analogous to convective available potential energy, except that it is related to the negative buoyancy associated with evaporative cooling of liquid water within a sinking cloudy air parcel. On a thermodynamic diagram, if a line is drawn corresponding to a sinking cloudy air parcel (follow a moist adiabat downward while the parcel is cloudy, and then after all liquid water has evaporated, continue below cloud base by following a dry adiabat), the EAPE is the area between this air-parcel line and a line corresponding to the environmental sounding. The resulting EAPE can be related to the kinetic energy associated with a negatively buoyant, sinking air parcel, and is useful for determining attributes of downdrafts and downbursts from thunderstorms.
Industry:Weather
A type of evaporation gauge or evaporimeter; it is a pan used in the measurement of the evaporation of water into the atmosphere. The U. S. Weather Bureau evaporation pan (Class-A pan) is a cylindrical container fabricated of galvanized iron or other rust-resistant metal with a depth of 25. 4 cm (10 in. ) and a diameter of 121. 9 cm (48 in. ). The pan is accurately leveled at a site that is nearly flat, well sodded, and free from obstructions. The water level is maintained at between 5 and 7. 5 cm (2 and 3 in. ) below the top of the rim, and periodic measurements are made of the changes of the water level with the aid of a hook gauge set in the still well. When the water level drops to 17. 8 cm (7 in. ), the pan is refilled. Its average pan coefficient is about 0. 7. See also BPI pan, Colorado sunken pan, floating pan, screened pan.
Industry:Weather
A general name for devices such as atmometers, evaporation pans, and lysimeters that measure evaporation in some fashion.
Industry:Weather
The Greek name for the stormy, rainy southeast wind. On the Tower of the Winds at Athens it is represented by an old man, warmly clothed and wrapped in his mantle.
Industry:Weather
Any of the fundamental equations of hydrodynamics expressed in Eulerian coordinates. These are so commonly used that the designation “Eulerian” is often omitted. See, for example, equations of motion.
Industry:Weather
