- Industry: Weather
- Number of terms: 60695
- Number of blossaries: 0
- Company Profile:
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, ...
An instrument for measuring the luminance, luminous intensity, or illuminance of a light source. Analogous to radiometer, but with an output weighted by the wavelength response of the human eye (i.e., scaled by luminous efficiency). It is common in historical literature to see this term used for any radiometer that responds primarily to wavelengths that are visible to the human eye, with or without scaling for luminous efficiency. A photometer used to measure the intensity of a distant light is sometimes referred to as a telephotometer or transmissometer. See hydrophotometer, radiometer.
Industry:Weather
An instrument for measuring the diffuse sky radiation. A shadow band is added to a conventional pyranometer at such an angle that it blocks out the direct solar radiation throughout the course of a day.
Industry:Weather
An instrument for measuring differences in electric potential. Essentially, this instrument balances the unknown voltage against a known, adjustable voltage. If the balancing is accomplished automatically, the instrument is called a self-balancing potentiometer. Potentiometers are frequently used in conjunction with thermocouples for measuring temperature.
Industry:Weather
An instrument designed to measure the effect of sunlight upon evaporation from plant foliage. It consists of a porous clay atmometer with a blackened surface so that it absorbs radiant energy.
Industry:Weather
An instrument designed to provide a direct estimate of water equivalence of a snowpack by measuring the pressure due to the mass of overlying snow.
Industry:Weather
An instrument for determining salinity of water (a salinometer) by measuring electrical conductivity of the water sample with a Wheatstone bridge.
Industry:Weather
An individual cyclonic-scale feature of atmospheric circulation, commonly used to denote either a high or a low, less frequently a ridge or a trough.
Industry:Weather
An indirect method of discharge measurement, especially after floods, by determining the water surface slope during the peak flow, by using the high water marks, a survey of two or more river cross sections along a stretch of the river, and by estimating the river roughness coefficient. The discharge is then calculated by the Manning equation or Chezy equation.
Industry:Weather
An index developed by McKee et al. (1993) to quantify precipitation deficit at a given location for multiple timescales. Standardized precipitation is the difference of precipitation from the mean for a specified time divided by the standard deviation, where the mean and standard deviation are determined from the climatological record. The fact that precipitation is not normally distributed is overcome by applying a transformation (i.e., gamma function) to the distribution.
Industry:Weather
