The change in barometric pressure within a specified period of time (typically 3 hours for meteorological observations).

In general, any self-recording instrument carried aloft by any means to obtain meteorological data.

An instrument for determining the degree of polarization of light. See photopolarimeter.

The rate of decrease of pressure per unit distance at a fixed time.

An approximation to the complete equations describing atmospheric motion in which only the terms most important for the growth and decay of synoptic scale extratropical weather systems (i.e., the large areas of high and low pressure seen on weather maps) ...

Having a specific relationship to a time base or clock. In synchronous communications, data characters are sent according to a timing signal which synchronizes the two communicating devices.

The ratio of the existing amount of water vapor in the air at a given temperature to the maximum amount that could exist at that temperature. Usually expressed in percent.

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

Situated on the side from which the wind blows.

An instrument for recording global solar radiation.

The lowest value of a measured quality at which a sensor responds. Compare to tracking.

The transducer's output when the maximum sensed value is applied to the transducer's input. For example, the F.S. output of a 4-20 mA transmitter is 20 mA, whereas its span is only 16mA.

An instrument which measures the intensity of radiation by determining the amount of chemical change( or fluorescence produced by that radiation.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

A defective maximum thermometer of the liquid-inglass type in which the mercury flows too freely through the constriction. Such a thermometer will indicate a maximum temperature that is too low.

A vent used with pressure sensors to reduce the effect of wind on the pressure inlet. It is normally mounted remotely and connected to the sensor using airtight tubing.

Same as wave pole.

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

A measure of the degree to which the weather or climate of a region is favorable to the process of evaporation. Usually considered to be the rate of evaporation. under existing atmospheric conditions, from a surface of water which is chemically pure and h ...

A line drawn through all points on a map having the same amount of cloudiness.