A subtle, diumal component of the wind velocity leading to a diumal shift of the wind or turning of the wind with the sun, produced bv the east-to-west progression of daytime surface heating.

The total area drained by a river and its tributaries. Same as watershed.

The volume of liquid water evaporated per unit area in unit time. usually measured as the depth of liquid water lost per unit time from the whole area.

An instrument for the measurement of the radon content of the atmosphere.

An instrument used for measuring the specific gravity of a liquid.

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

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.

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

A rain gauge which automatically records the amount of precipitation collected, as a function of time.

A cover which fits over a large inflated balloon to facilitate handling in high or gusty winds.

Rate of flow of water past a point in a stream, expressed as volume per unit time, i.e. cubic feet per second.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

Anemometer which measures wind speed by measuring the degree of cooling of a metal film heated by an electric current. A type of cooling-power anemometer.

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 ...

That stage, on a fixed river gauge, at which overflow of the natural banks of the stream begins to cause damage in any portion of the reach for which the gauge is used as an index.

A liquid-in-glass thermometer which uses an organic substance such as alcohol as the thermometer liquid. This type of thermometer has a low freezing point and a high coefficient of expansion. It is less accurate, however, than a mercury thermometer.

The difference between the solar radiation directed downward and upward; net flux of solar radiation.

The officially designated elevation of an airport above mean sea level, taken as the highest point on any of the runways of the airport. Same as airport elevation.

Solar radiation of selected wavelengths.

Same as instrument shelter.