A small balloon used to determine the height of the cloud base. The height can be computed from the ascent velocity of the balloon and the time required for its disappearance into the cloud.

An increase in the central pressure of a pressure system; opposite of a deepening. More commonly applied to a low rather than a high.

An instrument used to indicate wind direction.

A hypothetical, ideal body which absorbs completely all incident radiation. independent of wavelength and direction. No actual substance behaves as a true black body, although platinum black and other soots rather closely approximate this ideal. However, ...

An empirical curve relating stream discharge or stage at a point on a stream to discharge or stage at one or more upstream points and, possibly. to other parameters. Also called stage relation.

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

Same as contact anemometer.

A method of upper air observation consisting of an evaluation of the wind speed and direction, temperature, pressure, and humidity aloft by means of a balloon-borne radiosonde tracked by radar or a radio theodolite.

A photometer that measures the received intensity of a distance tight source.

Any device or instrument for measuring salinity, especially one based on electrical conductivity methods.

A wave resulting from the action of wind on a water surface.

A large body of air having similar horizontal temperature and moisture characteristics.

Upwarddirected solar radiation, reflected by the earth's surface and the atmosphere.

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 ...

The lowest temperature that can be obtained on a wet-bulb thermometer in any given sample of air. Obtained by evaporation of water (or ice) from the muslin wick. Used in computing dew point and relative humidity.

Difference between the temperatures of the dry-bulb and the wet-bulb thermometers of a psychrometer.

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

An instrument for recording global solar radiation.

A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.