See radar theodolite, radio direction-finder.

The gravity flow of water within soil.

The wind speed and direction at various levels in the atmosphere above the level reached by surface weather observations.

Pyrheliometer based on the comparison of the heating of two identical metal strips, one exposed to radiation, the other to a joule effect.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

A type of pressure-plate anemometer in which the plate, restrained by a stiff spring, is held perpendicular to the wind. The wind-activated motion of the plate is measured electrically. The natural frequency of this system can be made high enough so that ...

See hydrologic accounting.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

Same as fogbow.

The range of operating conditions within which a device is designed to operate and for which operating influences are stated. See operating conditions, reference operating conditions.

Solar radiation scattered by particles in the atmosphere.

Routine broadcast of meteorological information for aircraft in flight.

Same as dropsonde.

Nested Grid Model generated every 12 hours by NCEP.

The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

The stage on a fixed river gauge at which it is necessary to begin issuing warnings or river forecasts if adequate precautionary measures are to be taken before flood stage is reached.

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

The upper surface of a column of liquid.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.