An instrument for measuring the difference of the solar radiation falling on both sides of a horizontal surface from the whole hemisphere.

An instrument which measures the intensity of radiation by determining the amount of chemical change( or fluorescence produced by that radiation.

A measure of the intrinsic luminous intensity emitted by a source in a given direction. Luminance is a measure only of light. The comparable term for electromagnetic radiation in general is radiance.

A line drawn through geographical points having the same pluvial index.

Same as precipitation-evaporation ratio.

A graphical representation of a frequency distribution. The range of the variable is divided into class intervals for which the frequency of occurrence is represented by a rectangular column. The height of the column is proportional to the frequency of ob ...

Hygrometer in which the dew (frost) point is determined by observing the temperature of an artificially cooled surface at the moment at which dew (frost) first appears on it.

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

A conically shaped, copper rain gauge shield.

A unit of mass numerically equal to the molecular weight of the substance. The gram-mote or gram-molecule is the mass in grams numerically equal to the molecular weight, i.e. a gram-mole of oxygen is 32 grams.

A wind scale adapted by the U.S. Forest Service for use in the forested areas of the northern Rocky Mountains (NRM). It is an adaptation of the Beaufort wind scale. The difference between these two scales lies in the specification of the visual effects of ...

The standard deviation (positive square-root of the variation) of the errors associated with physical measurements of an unknown quantity, or statistical estimates of an unknown parameter or of a random variable.

Wind with a speed between 56 and 63 knots (64 and 72 mph); Beaufort scale number 11.

In Jeffreys' classification, a wind for which the pressure force exactly balances the viscous force, in which the vertical transfers of momentum predominate.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...

Downward-facing pyranometer used for measuring reflected solar radiation.

Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

Complementary Metal-Oxide Semiconductor. A method of making silicon chips that results in low power consumption by the circuits.

The total electromagnetic radiation emitted by the sun. About 99.9 percent of its energy output falls within the wavelength interval from 0. 15 microns to 4.0 microns, with peak intensity near 0.47 microns. About one-half of the total energy in the solar ...