An instrument which measures the spectral distribution of the intensity of direct solar radiation.

A thermopile used in some types of radiation instruments. See solarimeter.

The probability distribution of random errors, typically a normal distribution with a zero mean.

film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

Air in motion relative to the surface of the earth. Almost exclusively used to denote the horizontal component.

pattern barometer-Mercurial barometer with a fixed scale and cistern and which therefore requires only one adjustment before each reading.

An instrument consisting of a series of graduated cylinders possessing selective collection efficiencies. It is used for the measurement of quantities relating to the size distribution of cloud droplets.

Abbreviation for radio frequency.

A modification of the dew cell used in radiosonde equipment.

A recording siphon barometer.

An anemometer utilizing the principle that the pitch of the aeolian tones generated by air moving past an obstacle is a function of the speed of the air. Largely a curiosity and has been put to no practical application in modem meteorology.

Pertaining to measurements or devices in which the output vanes in discrete steps, i.e. on-off or pulse signals. Compare to analog.

A reversing thermometer which is encased in a strong glass outer shell that protects it against hydrostatic pressure. Compare to unprotected thermometer.

Read Only Memory. A memory that cannot be altered in normal use of a computer, Usually used to store information permanently, such as firmware programs.

A systematic summary of the terms (inflow, outflow, and storage) of the storage equation as applied to the computation of soil-moisture changes, ground-water changes, etc. An evaluation of the hydrologic balance of an area. Also called basin accounting, w ...

For a given location, a measure of the long-range effectiveness of precipitation in promoting plant growth. Also called precipitation-evaporation index.

A generic term for any machine that enables a human being to communicate with a computer.

Wind with a speed below 1 knot (1 mph); Beaufort scale number 0.

See stage.