The maximum difference in output for any given input (within the specified range) when the value is approached first with increasing, and then with decreasing, input signals. Caused by energy absorption in the elements of the measuring instrument. Usually ...

Root Mean Square. This notation is used frequently with error analysis. In that context, it is the square root of the arithmetic mean of the squares of the deviations of the individual calibration points from the theoretical or ideal response.

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

A set of rules or conventions used to standardize data transfer between devices.

A record obtained from a meteorograph. A chart in which meteorological variables are plotted against time.

A pressure-operated switching device used in a radiosonde. In operation, the expansion of an aneroid capsule causes an electrical contact to scan a radiosonde commutator composed of conductors separated by insulators.

The gravity flow of water within soil.

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

The downward flux of atmospheric radiation passing through a given level surface, usually taken as the earth's surface. This result of infrared (long-wave) absorption and reemission by the atmosphere is the principal factor in the greenhouse effect.

Contraction for radiosonde observation.

A colloquial term in western Australia for a squall, associated with thunder, on the northwest coast in summer.

United Kingdom forecast model. (Available via AccuWeather.com Professional.)

In general, the transformation of data from a "raw" form to some useable form. In meteorology, this often refers to the conversion of the observed value of an element to the value which it would theoretically have at some selected or standard level. The m ...

Difference between the temperatures of the dry-bulb and the wet-bulb thermometers of a psychrometer.

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

An atmometer which uses a filter paper disc as the evaporating element. The amount of water evaporated through the paper is read at the graduated tube reservoir.

Movernent of water through the soil surface into the soil, or the quantity of water entering the soil. Infiltration is equal to the total precipitation less the losses due to interception by vegetation. retention in depressions on the land surface, evapor ...

Automated Weather Observing Station. A self-contained weather station designed to make aviation weather observations without operator involvement.

A Sunshine recorder of the type in which the time scale is supplied by the motion of the sun. The instrument, which is pointed at the celestial pole, consists of a hemispherical mirror mounted externally on the optical axis of a camera. The lens of the ca ...

Abbreviation for radio frequency.