Temperature assumed by an unsaturated air parcel when brought adiabatically to a standard pressure (1,000 mb).

A scale of yellows, greens, and blues for recording the color of sea water, as seen against the white background of a Secchi disk.

Wind with a speed between 11 and 16 knots (13 and 18 mph); Beaufort scale number 4.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

An instrument for determining the degree of polarization of light. See photopolarimeter.

A recording siphon barometer.

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

Radiation with wavelengths greater than 4 microns. (In meteorology, same as infrared radiation.)

Same as geostrophic wind level.

A system of designating meteorological observing stations by number. established and administered by the World Meteorological Organization. Under this scheme, specified areas of the word are divided into "blocks" each bearing a two-number designator. Stat ...

Line drawn through geographical points recording equal amounts of precipitation during a given time period or for a particular storm.

Snow shower, particularly of a very light and brief nature.

Same as rain gauge.

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

Contraction for pilot balloon observation.

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

Precipitation of very small, white opaque particles of ice, fairly flat or elongated, with diameters less than 1 mm. The solid equivalent of drizzle.

See radiation shield.

A sudden, significant increase in station pressure.