Liquid water at temperatures colder than freezing.

An instrument consisting of a series of graduated cylinders possessing selective collection efficiencies. It is used for the measurement of quantities relating to the size distribution of cloud droplets.

Rate of flow of water past a point in a stream, expressed as volume per unit time, i.e. cubic feet per second.

The volume of liquid water evaporated per unit area in unit time. usually measured as the depth of liquid water lost per unit time from the whole area.

Companion to the wet-bulb thermometer in a psychrometer. Used to measure ambient air temperature.

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

A technique for making winds aloft observations in which two theodolites located at either end of a baseline follow the ascent of a pilot balloon. Synchronous measurements of the elevation and azimuth angles of the balloon. taken at periodic intervals, pe ...

See calorie.

Same as an upper air observation, but commonly used to refer to a single complete radiosonde observation.

Same as ombrometer.

A high-altitude sounding system consisting of a small solid- propellant research rocket carried aloft by a large plastic balloon. The rocket is fired near the maximum altitude of the balloon flight.

A small, limited-capacity central processing unit contained entirely on one semiconductor chip.

A particular pattern of snow sampler having an internal diameter of 1.485 inches so that each inch of water in the sample weighs one ounce.

The process by which water in plants is transferred as water vapor to the atmosphere. Also, the amount of water so transferred.

An anemometer which measures wind speed in terms of the drag which the wind exerts on a solid body. See bridled-cup anemometer, normal-plate anemometer, pendulum anemometer.

A protocol similar to RS232 which makes use of differential transmission to provide high speed data transmission over significantly longer distances.

Solar and terrestrial radiation directed downwards (towards the earth's surface); incoming radiation.

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

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

A measure of the intrinsic luminous intensity emitted by a source in a given direction. Luminance is a measure only of light. The comparable term for electromagnetic radiation in general is radiance.