An instrument developed by K. Angstrom for measuring the effective terrestrial radiation. It consists of four manganin strips, of which two are blackened and two are polished. The blackened strips are allowed to radiate to the atmosphere while the polishe ...

A medium-sized instrument shelter. It is a white louvered box with a flat double to of and is mounted four feet above the ground on a four-legged stand.

A balloon used to carry a radiosonde aloft, considerably larger than pilot balloons or ceiling balloons.

Abbreviation for precipitation effectiveness index.

The level at which ice crystals and snowflakes melt as they descend through the atmosphere.

Same as atmometer.

National Weather Service. Administered by the U.S. Department of Commerce.

Liquid water at temperatures colder than freezing.

The inherent imprecision of a given process of measurement, the unpredictable component of repeated independent measurements of the same object under sensibly uniform conditions.

A sunshine recorder of the type in which the time scale is supplied by a chronograph. It consists of two bulbs, one of which is blackened, which communicate through a glass tube of small diameter. The tube is partially filled with mercury and contains two ...

Strong winds concentrated within a narrow band in the atmosphere. The jet stream often "steers" surface features such as front and low pressure systems.

Electromagnetic radiation lying within the wavelength interval to which the human eye is sensitive, the spectral interval from approximately 0.4 to 0.7 microns (4000 to 7000 angstroms). Bounded on the short-wavelength end by ultraviolet radiation and on t ...

A mercury-in-glass thermometer which records the temperature upon being inverted and retains its reading until being returned to the first position.

A type of disk hardness-gauge, especially useful in relatively soft snow. See disk hardness gauge.

A hypothetical temperature characterized by a complete absence of heat and defined as 0 K, -273.15 C, or -459.67 F.

A magnetometer of the electromagnetic type which is used to measure the horizontal intensity of the earth's magnetic field.

In a system of moist air, the dimensionless ratio of the mass of water vapor to the mass of dry air. For many purposes, the mixing ratio may be approximated by the specific humidity.

Dihydrogen oxide, molecular formula H2O.

A graphical representation of stage or discharge at a point on a stream as a function of time.

Anemometer whicb measures wind speed by measuring the degree of cooling of a metal wire heated by an electric current. A type of cooling power anemometer.