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.

Same as atmometer.

Erasable Programmable Read Only Memory. Programable read-only memory which can be erased, usually by ultraviolet light, and re-programmed.

Same as an upper air observation, but commonly used to refer to a single complete radiosonde observation.

A photoelectric spectrophotometer which is used in the determination of the ozone content of the atmosphere.

A clay atmometer consisting of a hollow ceramic sphere through which evaporation occurs. Evaporation is measured by the loss of water from the reservoir which feeds the sphere.

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

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

A line of equal or constant pressure.

The record or trace made by a microbarograph.

The transducer of any hygrometer, i.e. that part of a hygrometer that quantitatively "senses" atmospheric water vapor.

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 ...

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 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).

The general term for dry atmospheric suspensoids, including dust, haze, smoke. and sand. Compare to hydrometeor.

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

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

Apparatus designed to measure and record the size distribution of raindrops as they occur in the atmosphere.

Wind with a speed between 34 and 40 knots (39 and 46 mph); Beaufort scale number 8.