See constant-level balloon.

A metallic element of atomic weight 200.6 1, unique (for metals) in that it remains liquid under all but very extreme temperatures.

A hygrometer which uses a transducing element whose electrical properties are a function of atmospheric water vapor content. The humidity strip and carbon-film hygrometer element are examples of such a transducer.

Precipitation of white, opaque, spherical or conical ice particles that are crisp and easily crushed and that have diameters of 2 to 5 mm.

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

A photometric unit of illuminance or illumination equal to one lumen per square centimeter.

A wave resulting from the action of wind on a water surface.

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

The humidity transducinu element in a Diamond-Hinman radiosonde. Also called electrolytic strip.

Quantitative Precipitation Forecast.

A small balloon whose ascent is followed by a theodolite in order to obtain data for the computation of winds aloft.

The temperature at which a solid substance undergoes fusion, i.e. melts, changes from solid to liquid form. All substances have their characteristic melting points. For very pure substances the temperature range over which the process of fusion occurs is ...

A wind blowing in a direction opposite to the heading of a moving object, thus opposing the object's intended progress; the opposite of a tailwind.

Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.

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

A barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

A flower-like diagram indicating the relative frequencies of different wind directions for a given station and period of time.

The difference between downward and upward (total) radiation; net flux of all radiation.

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

That part of snow melt that reaches stream channels as runoff.