An apparatus, used in studying soil temperatures, for measuring the total supply of heat during a given period.

Conditions to which a device is subjected, not including the variable measured by the device. See normal operating conditions, reference operating conditions.

The process by which one object becomes adhered to another by the binding action of ice.

Reduction of visibility by strong winds blowing across dry ground with little or no vegetation. Visibilities of 1/8 mile or less over a widespread area are criteria for a Blowing Dust Advisory.

film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

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

A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity. The angular deflection of the plate is a function of the wind speed. This instrument is not used for station mea ...

Same as evaporative power.

A type of pressure-plate anemometer in which the plate, restrained by a stiff spring, is held perpendicular to the wind. The wind-activated motion of the plate is measured electrically. The natural frequency of this system can be made high enough so that ...

The measurement and computation of wind speeds and directions at various levels above the surface of the earth. Methods include pilot balloon observations, rabals, rawin or rawinsonde observations, radar tracking, or acoustic sounding.

The difference between the true value of some quantity and its observed value. Every observation is subject to certain errors. Systematic errors affect the whole of a series of observations in nearly the same way. For example, the scale of an instrument m ...

Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

Wind with a speed between 28 and 55 knots (32 and 63 mph); Beaufort scale numbers 7 through 10.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.

See calorie.

A mercury barometer which measures atmospheric pressure by weighing the mercury in the column or cistern.

That part of snow melt that reaches stream channels as runoff.

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 ...