Wind with a speed between 28 and 33 knots (32 and 38 mph); Beaufort scale number 7.

The total electromagnetic radiation emitted by the sun. About 99.9 percent of its energy output falls within the wavelength interval from 0. 15 microns to 4.0 microns, with peak intensity near 0.47 microns. About one-half of the total energy in the solar ...

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.

A hygrometer in which the rotation of the hygrometric element is a function of humidity.

Precipitation composed of white or translucent ice crystals, chiefly in complex branched hexagonal forms.

The most common of the principal rainbow phenomena, which appears as an arc of about 42

A self-recording psychrometer.

A precipitation amount of less than 0.005 inches. Also, the record made by any self-registering instrument.

Solar radiation of selected wavelengths.

The physical exposure of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and not always correctable. The purpose of the instrument shelter is to prov ...

A line drawn through points of equal humidity on given surface.

In aviation terminology, route or terminal weather conditions of sufficiently low visibility to require the operation of aircraft under instrument flight rules.

The boundary between the troposphere and stratosphere, usually characterized by an abrupt change in lapse rate. Its height varies from 10 to 20 km. Regions above the tropopause have greater atmospheric stability than regions below.

Any conventional barometer fitted with an extended scale so that atmospheric pressure measurements may be made at both high and low altitudes.

Determination of the total amount of snow covering a watershed or a given region. Both depth and water content of the snow may be measured, and the results may be used to predict the amount of water that will be available after melting.

The rate of decrease of pressure per unit distance at a fixed time.

Pertaining to rain, or more broadly, to precipitation.

Same as geostrophic wind level.

Diffuse solar radiation which has the same intensity in all directions.

A mercury barometer arranged so that the position of the upper or lower meniscus may be measured photographically. In one design the image of the meniscus is formed on a rotating drum covered with sensitized paper so that a continuous record of pressure a ...