A type of atmometer. It is a pan used in the measurement of the evaporation of water into the atmosphere. The NWS Class A pan is a cylindrical container 48 inches in diameter and 10 inches deep.

An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states. Thermometers may be classified into types according to their construction; deformation thermometer, electrical t ...

In general. the severe wind of an intense tropical cyclone (hurricane or typhoon). The term has no further technical connotation, but, unfortunately, is easily conftlsed with the strictly defined hurricane-force wind,

Apparatus designed to measure and record the size distribution of raindrops as they occur in the atmosphere.

Temperarure at which a liquid solidifies under any given set of conditions. It may or may not be the same as the melting point or the more rigidly defined true freezing point or (for water) ice point.

A rain gauge which indicates but does not record the amount of precipitation captured.

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

In general, any object that reflects incident energy. Usually it is a device designed for specific reflection characteristics.

A unit of pressure used principally in oceanography. One decibar (10' dynes/cm2) equals 0.1 bar. In the ocean, hydrostatic pressure in decibars very nearly equals the corresponding depth in meters.

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

An absolute pyhrliometer, developed by C.G. Abbott, in which the radiation-sensing element is a blackened water-calorimeter.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

Abbreviation for radio frequency.

The distance or length of flow of the air past a point during a given interval of time.

Any one of numerous devices for the measurement of either speed alone or of both direction and speed (set and drift) in flowing water.

Abbreviation for precipitation-evaporation quotient.

Not a linear function of the relevant variables.

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

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

As used by the U.S. Army Corps of Engineers, the departure (in