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

A plastic molding component formed by the reaction of phenol and formaldehyde. It can be heavily reinforced or "filled" with glass fibers or other materials. Phenolics are known for their high impact strength, excellent wear characteristics, and dimension ...

Literally "not wet", containing no liquid.

An instrument designed to measure the effect of sunlight on evaporation from plant foliage. It consists of a porous clay atmometer whose surface has been blackened so that it absorbs radiant energy.

Infrared radiation emitted by or being propagated through the atmosphere.

An instrument for the measurement of the rate of ice accretion on an unheated body.

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.

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

In a system of moist air, the dimensionless ratio of the mass of water vapor to the total mass of the system.

Upwarddirected solar radiation, reflected by the earth's surface and the atmosphere.

Solar radiation of selected wavelengths.

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

The smallest change in the environment that causes detectable change in the indication of an instrument. Compare to sensitivity.

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.

In aviation terminology, route or terminal weather conditions of sufficiently low visibility to require the operation of aircraft under instrument flight rules.

General name for an instrument which measures the earth's magnetic field intensity.

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

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.

Radiation coming from the solid angle of the sun's disc, as opposed to diffuse sky radiation, effective terrestrial radiation, or radiation from any other source. Direct solar radiation is measured by pyrheliometers.

A surface weather observation, made at periodic times, of sky cover, state of the sky, cloud height, atmospheric pressure reduced to sea level, temperature, dew point, wind speed and direction. amount of precipitation, hydrometeors and lithometeors. and s ...