The envelope of air surrounding the earth and bound to it more or less permanently by virtue of the earth's gravitational attraction. The system whose chemical Properties. dynamic motions, and physical processes constitute the subject matter of meteorolog ...

A rain gauge capable of measuring very small amounts of precipitation. Also called micropluviometer, trace recorder.

meter-An instrument for measuring the transmissivity of the atmosphere; a type of transmissometer. It consists of a constant- intensity collimated light source located at a suitable distance from a photoelectric cell. Variation in the turbidity of the atm ...

An instrument used for measuring the specific gravity of a liquid.

In meteorology, an area of low pressure; a low or trough.

Reduction of visibility by strong winds blowing across dry ground with little or no vegetation. Visibilities of 1/8 mile or less over a widespread area are criteria for a Blowing Dust Advisory.

A precipitation amount of less than 0.005 inches. Also, the record made by any self-registering instrument.

The depth below which the ground is saturated with water. No water table exists if the ground water is confined by an overlying impermeable stratum, as in the case of artesian ground water.

The time required for an instrument to register a designated percentage (frequently 90%) of a step change in the variable being measured.

A constant which describes the performance of a wind vane in response to a step change in wind direction. It is calculated from the relative amount of overshoot on two successive swings (half cycles) of a decaying oscillation. This specification is dimens ...

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.

A temperature scale based on absolute zero. Same as Kelvin temperature scale.

Facing away from the wind.

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.

A conductor or system of conductors for radiating and/or receiving radio energy. Also called aerial.

The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

A recording siphon barometer.

Formation of a single water drop by the union of two or more colliding drops.

Barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.

An instrument resulting from the combination of a thermograph and a hygrograph and furnishing, on the same chart, simultaneous time recording of ambient temperature and humidity.