The temperature to which a sample of air must be cooled, while the mixing ratio and barometric pressure remain constant, in order to attain saturation by water vapor. When this temperature is below O

A type of wind vane having a split or V-shaped tail. The apex orients itself to the direction of the wind.

The outer, solid portion of the earth: the crust of the earth.

Precipitation of white, opaque, spherical or conical ice particles that are crisp and easily crushed and that have diameters of 2 to 5 mm.

A mercury barometer of the fixed cistern type in which a moveable scale terminating in an ivory point is used to compensate for the variations in the height of the mercury in the cistern

The quantity to be measured (or modulated, or detected, or operated upon) which is received by an instrument. Thus, for a thermometer. temperature is the input quantity.

The process by which water in plants is transferred as water vapor to the atmosphere. Also, the amount of water so transferred.

A rocket designed primarily for routine upper air observations in the lower 250,000 feet of the atmosphere, especially that portion inaccessible to balloons (above 100,000 feet).

A hygrometer based upon the diffusion of water vapor through a porous membrane.

A colorless and odorless gaseous element. The lightest and apparently the most abundant chemical element in the universe. However, it is found only in trace quantities in the observable portion of our atmosphere, only about 0.00005 percent by volume of dr ...

A defective maximum thermometer of the liquid-inglass type in which the mercury flows too freely through the constriction. Such a thermometer will indicate a maximum temperature that is too low.

Thermometer for measuring the temperature in the soil at different depths.

The record or trace made by a microbarograph.

An instrument for measuring the ultraviolet in solar and sky radiation.

Companion to the wet-bulb thermometer in a psychrometer. Used to measure ambient air temperature.

A record obtained from a meteorograph. A chart in which meteorological variables are plotted against time.

A relatively small-scale, downward moving current of air.

An instrument for measuring snow hardness in terms of the resistance of snow to the pressure exerted by a disk attached to a spring-loaded rod, a gauge calibrated in pounds per square inch registers the amount of resistance. See Canadian hardness gauge.

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

A spring which is designed to achieve a fixed spring constant over a wide temperature range. Usually, this involves an alloy with high nickel content such as Ni-Span C. It is common for these springs to be stress relieved at elevated temperature after for ...