See radiation shield.

Same as evaporative power.

Apparatus designed to measure the amount of precipitation falling in the form of snow. The device determines the weight of the snow or the volume of water after the snow melts.

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

Psychrometer to which a small chain or rotary handle is attached so that the observer can rotate the instrument rapidly to properly ventilate the thermometer bulbs.

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

A sudden, significant increase in station pressure.

Instrument used to measure the amount of water evaporated from the soil surface during a given time interval.

Snow gauge composed of a metal cylinder, closed at one end, used to obtain a sample of snow from which the water is measured after melting.

The processing of the form or mode of a signal so as to make it intelligible to, or compatible with, a given device.

Contraction for pilot balloon observation.

Operation mode of a communication circuit in which one end can only transmit and the other end can only receive.

Radiation with wavelengths less than 4 microns.

An aneroid barometer with a scale graduated in altitude instead of pressure units.

An instrument for measuring differences in electric potential.

A large plastic constant-level balloon for duration flying at very high altitudes.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

Meteorological information issued by a watch office concerning the occurrence or forecast of weather phenomena which may affect the safety of aircraft operations.

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

A cone-tipped metal rod designed to be driven downward into deposited snow or firn. The measured amount of force required to drive the rod a given distance is an indication of the physical properties of the snow or firn.