Balance of the water resources of a region, comparing precipitation and inflow with outflow, evaporation, and accumulation.

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

Contraction for radiosonde observation.

The temperature to which a sample of air must be cooled, while the mixing ratio and barometric pressure remain constant, in order to attain saturation by water vapor. When this temperature is below O

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

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged.

A feeble oscillatory disturbance of the earth's crust, detectable only by very sensitive seismographs. Certain types of microseisms seem to be closely correlated with pressure disturbances. See microbarm.

The group of bits which a computer processes as a unit; often, 8 bits.

The value of atmospheric pressure to which the scale of a pressure altimeter is set so as to indicate airport elevation. The altimeter setting is included as part of an aviation weather observation.

Same as wave pole.

A hygrometer in which the sensitive element is a strand or strands of human hair, the length of which is a function of the relative humidity of the air.

Cathode Ray Tube. A display element, consisting of a vacuum tube and screen, used with computers.

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.

The difference between the input quantity applied to a measuring instrument and the output quantity indicated by the instrument. The inaccuracy of an instrument is equal to the sum of its instrument error and its uncertainty.

An instrument whose calibration can be determined by means of simple physical measurements on the instrument. Compare to secondary instrument.

See gust and peak gust.

The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states. Thermometers may be classified into types according to their construction; deformation thermometer, electrical t ...

The size of the area comprising a watershed or river basin. Also called catchment area.

The distance or length of flow of the air past a point during a given interval of time.