A scale of yellows, greens, and blues for recording the color of sea water, as seen against the white background of a Secchi disk.

In general, solar radiation received at the earth's surface. Contracted from incoming solar radiation.

Complementary Metal-Oxide Semiconductor. A method of making silicon chips that results in low power consumption by the circuits.

A contact anemometer connected to an electrical circuit which is so arranged that the average wind speed is indicated.

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

An instrument which measures the instantaneous rate at which rain is falling on a given surface. Also called a rate-of-rainfall gauge.

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

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

Transmitted energy which is modulated in order to carry information. Usually, it is in the form of a radio- frequency sine wave, modulated either in amplitude or in frequency.

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

An elongated area of relatively high pressure. Usually associated with and most clearly identified as an area of maximum anticyclonic curvature of the wind flow. The opposite of a trough.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

A recording hair hygrometer.

The volume of water required to cover one acre to a depth of one foot: 43,560 cubic feet.

The wind speed and direction at various levels in the atmosphere above the level reached by surface weather observations.

An instrument for measuring the difference of the solar radiation falling on both sides of a horizontal surface from the whole hemisphere.

Readily taking up and retaining moisture.

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

See wind vane.

An instrument for taking photographs of an image of the sun in monochromatic light.