A recording variometer.

A river gauge in which a weight suspended on a wire is lowered to the water surface from a bridge or other overhead structure to measure the distance from a point of known elevation to the water surface.

The degree of conformity of an indicated value to an accepted standard value, or ideal value. See accuracy rating, measured accuracy.

In general, the transformation of data from a "raw" form to some useable form. In meteorology, this often refers to the conversion of the observed value of an element to the value which it would theoretically have at some selected or standard level. The m ...

Frozen or partly frozen rain.

A photometer which measures the intensity of radiation as a function of the frequency (or wavelength) of the radiation.

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

A transducer for converting thermal energy directly into electrical energy. It is composed of pairs of thermocouples which are connected either in series or in parallel. Thermopiles are used in thermoelectric radiation instruments when the output of a sin ...

A c.g.s. (centimeter-gram-second) unit of mass. Originally defined as the mass of 1 cubic centimeter of water at 4

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

A sounding balloon which, when operationally inflated, resembles an inverted teardrop.

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

A relatively small-scale, upward moving current of air.

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

The maximum distance along the runway at which the runway lights are visible to a pilot at touchdown. Runway visual range may be determined by an observer located at the end of the runway, facing in the direction of landing, or by means of a transmissomet ...

An instrument for the measurement of the rate of ice accretion on an unheated body.

A buoyant balloon rising freely in the atmosphere, as opposed to a captive balloon.

An instrument which indicates the presence of precipitation. The ombroscope consists of a heated, water-sensitive surface which indicates by mechanical or electrical techniques the occurrence of precipitation.

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 clay atmometer consisting of a hollow ceramic sphere through which evaporation occurs. Evaporation is measured by the loss of water from the reservoir which feeds the sphere.