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

A line of equal or constant temperature.

NEXt Generation RADar. A NWS network of about 140 Doppler radars operating nationwide.

Hygrometer in which the dew (frost) point is determined by observing the temperature of an artificially cooled surface at the moment at which dew (frost) first appears on it.

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

A mercury barometer in which the tube is U-shaped and the upper and lower mercury surfaces have the same diameter.

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

A radar term for a single pulse of radio energy.

An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen which graphs a record on a rotating drum. Sometimes called aneroidograph.

A photoelectric spectrophotometer which is used in the determination of the ozone content of the atmosphere.

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.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

In physics, any process in which the flux density (or power, amplitude, intensity, illuminance, etc.) of a "parallel beam" of energy decreases with increasing distance from the source. Attenuation is always due to the action of the transmitting medium its ...

Conditions to which a device is subjected, not including the variable measured by the device. See normal operating conditions, reference operating conditions.

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 total area drained by a river and its tributaries. Same as river basin.

An atmospheric sounding instrument which is supported by a captive balloon and used to obtain temperature and humidity data from the ground level to a height of a few thousand feet. The data is telemetered to the ground through a wire cable.

A device for measuring the frequency of occurrence of atmospherics whose intensity is greater than a predetermined level.

A diagram showing the intensity of the radiation field in all directions from a transmitting radio or radar antenna at a given distance from the antenna.

Pertaining to the action or effect of the wind. Derived from the name of the Greek god of the winds, Aeolus.