in United States weather observing practice, the highest "instantaneous" wind speed recorded at a station during a specified period, usually the 24-hour observation day. Therefore, a peak gust need not be a true gust of wind.

Same as mirror nephoscope.

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

See calorie.

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

A very sensitive electrostatic electrometer for measuring small potential differences.

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

Any sudden and heavy rain, almost always of the shower type.

The atmospheric pressure at mean sea level either directly measured by stations at sea level or empirically determined from the station pressure and temperature by stations not at sea level. Used as a common reference for analyses of surface pressure patt ...

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

A instrument designed to study small fluctuations of some quantity. The microbarograph is an example of a recording pressure variometer.

Same as windsock.

See hydrologic accounting.

A general term for instruments designed to measure the amount of cloudiness.

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.

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, ...

(1) The initial component or the sensing element of a measuring system. For example, the receiver of a rain gauge is the funnel which captures the rain and the receiver of a thermoelectric thermometer is the measuring thermocouple. (2) An instrument used ...

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 ...

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.

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