A wind blowing in the same direction as the heading of a moving object. thus assisting the object's intended progress. The opposite of a head wind.

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

A rain gauge which indicates but does not record the amount of precipitation captured.

A self-recording thermometer.

Diffuse solar radiation which has the same intensity in all directions.

Small particle on which water vapor condenses.

National Weather Service. Administered by the U.S. Department of Commerce.

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 ...

A mercury barometer which measures atmospheric pressure by weighing the mercury in the column or cistern.

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 ...

Same as dew-point hygrometer.

(1) The ratio of the speeds of a chemical reaction at two temperatures differing by 10

A fabric cone attached to a metal ring and used to indicate wind direction. often at airfields.

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

A measure of long-term precipitation effectiveness. The ratio of the normal annual rainfall to the normal annual evaporation.

A unit of energy defined as the heat required to raise the temperature of one pound of water one degree Fahrenheit. It is equal to 252.1 calories or to 1055 joules.

The general term for dry atmospheric suspensoids, including dust, haze, smoke. and sand. Compare to hydrometeor.

Barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.

Name sometimes given to a transmissometer.

Phase Shift Keying. A form of phase modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.