See hydrologic accounting.

A device for measuring sea-surface waves. It consists of a weighted pole below which a disk is suspended at a depth sufficiently deep for the wave motion associated with deepwater waves to be negligible. The pole will then remain nearly as if anchored to ...

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

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, ...

The state of the weather with respect to its effect upon the kindling and spreading of forest fires.

Wind with a speed between 4 and 6 knots (4 and 7 mph), Beaufort scale number 2.

A rotation anemometer in which the axis of rotation is horizontal. The instrument has either flat vanes (as in the air meter) or helicoidal vanes (as in the propeller anemometer). The relation between wind speed and angular rotation is almost linear.

Air in motion relative to the surface of the earth. Almost exclusively used to denote the horizontal component.

See calorie.

A unit of energy defined as the heat required to raise the temperature of one pound of water one degree Fahrenheit. It is equal to 252.1 calories or to 1055 joules.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

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.

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

A form of data transmission in which the bits of each character are sent one at a time along a single communication path. Compare to parallel data transmission.

The difference between temperature measurements taken at two significant levels above the ground. Temperatures at 10 and 40 meters are commonly used.

In folklore, a name for wind.

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

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

An old nautical term for mercury barometer.