The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

The line-of-sight distance between two objects.

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.

Winds which, over a small area, differ from those which would be appropriate to the general pressure distribution.

Pertaining to measurements or devices in which the output varies continuously, i.e. voltage or rotation signals. Compare to digital.

A balloon designed to float at a constant pressure level. This may be accomplished by a pressure valve which controls the release of ballast so as to maintain flight above a selected pressure level until the supply of ballast is exhausted. See Moby Dick b ...

A computed characteristic of a particular river basin, expressed as the time difference between the time-center of mass of rainfall and the time-center of mass of resulting runoff.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.

A type of modulation in which the frequency of a continuous radio carrier wave is varied in accordance with the properties of a second (modulating) wave.

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

Same as fogbow.

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

Wind with a speed between 41 and 47 knots (47 and 54 mph); Beaufort scale number 9.

An instrument for measuring the extinction coefficient in water.

A measure, proposed by Angstrom, of the precipitation effectiveness of a region.

A wind blowing in the same direction as the heading of a moving object. thus assisting the object's intended progress. The opposite of a head wind.

An inert gas. An element found in the atmosphere to the extent of only 0.000114 percent by volume. Its molecular weight is 83.7.

The time required for an instrument to registe 63.2% of a step change in the variable being measured.

An instrument used to measure the water vapor content of the air.

Programs or instructions which are stored in readonly memory.