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

The change in barometric pressure within a specified period of time (typically 3 hours for meteorological observations).

Same as recording rain gauge.

A photometer which measures the intensity of radiation as a function of the frequency (or wavelength) of the radiation.

The mass density of a parcel of air expressed in units of mass per volume.

The energy of any type of electromagnetic radiation. Also called radiation.

A subtle, diumal component of the wind velocity leading to a diumal shift of the wind or turning of the wind with the sun, produced bv the east-to-west progression of daytime surface heating.

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

Negative Vorticity Advection.

See hydrologic accounting.

A system of physical units based on the use of the centimeter, gram. and the second as elementary quantities of length. mass. and time.

A fixed-length group of bits representing the large data element handled as a unit by a computer. Word length is determined by the capacity of the CPU registers.

Apparatus using the combined simultaneous action of a bimetallic thermometer and a hair hygrometer to move a needle in front of a divided scale. fts construction permits dew point variations to be indicated approximately.

A thermometer using transducing elements which deform with temperature. Examples are the bimetallic thermometer and the Bourdon tube type of thennometer.

A system of estimating and reporting wind speed, originally based on the effect of various wind speeds on the amount of canvas that a full-rigged nineteenth century frigate could carry.

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.

The process of modifying some characteristic of a wave (the carrier) so that it varies in step with the instantaneous value of another wave (the modulating wave) in order to transmit a message. The modified characteristic may be frequency, phase, and/or a ...

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

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.