Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

General name for an instrument which measures the earth's magnetic field intensity.

A graphical aid used in fire weather forecasting to calculate the degree of forest-fire danger (or burning index). Commonly in the form of a circular slide rule, the firedanger meter relates numerical indices of (a) the seasonal stage of foliage, (b) the ...

National Weather Service. Administered by the U.S. Department of Commerce.

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.

Difference between the instantaneous wind velocity at a point and the mean wind velocity taken over a given time interval. Also called fluctuation velocity.

A reflecting type telescope with a 45

A hypothetical "body" whose surface absorbs no electromagnetic radiation of any wavelength. An idealization exactly opposite to that of the black body. In nature, no true white bodies are known. Moist white pigments exhibiting high reflectivity for visibl ...

A mercury barometer designed for use aboard ship. The instrument is of the fixed-cistern type (see Kew barometer). The mercury tube is constructed with a wide bore for its upper portion and with a capillary bore for its lower portion. This is done to incr ...

A thermograph in which ventilation is provided by a suction fan.

See feed.

A thermometer consisting of a clock mechanism the speed of which is a function of temperature.

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.

A hygrometer which uses a transducing element whose electrical properties are a function of atmospheric water vapor content. The humidity strip and carbon-film hygrometer element are examples of such a transducer.

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

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

See radiosonde commutator.

A very sensitive electrostatic electrometer for measuring small potential differences.

The record of an aneroid barograph.

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