An instrument consisting of a series of graduated cylinders possessing selective collection efficiencies. It is used for the measurement of quantities relating to the size distribution of cloud droplets.

The record of an aneroid barograph.

The probability distribution of random errors, typically a normal distribution with a zero mean.

A type of anemometer in which the rotation of an element serves to measure the wind. Rotation anemometers are divided into two classes; those in which the axis of rotation is horizontal, such as the windmill anemometer, and those in which the axis of rota ...

An instrument which measures the effective terrestrial radiation. See Angstrom pyrgeometer.

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

A rainbow formed by light rays which have been reflected from an extended water surface. Not to be confused with a reflected rainbow whose image may be seen in a still body of water. The center of a reflection rainbow is at the same elevation as the sun b ...

A mercury-in-glass thermometer which records the temperature upon being inverted and retains its reading until being returned to the first position.

Abbreviation for radio frequency.

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

A buoyant balloon kept from rising freely by means of a line secured to a point on the ground, as opposed to a free balloon. See kytoon.

A device used on certain types of instruments to prevent unwanted radiation from affecting the measurement of a quantity. Also called solar radiation shield.

A rain gauge which is placed under trees or foliage to determine the rainfall in that location. By comparing this catch with that from a rain gauge set in the open. the amount of rainfall which has been intercepted by foliage can be determined.

The sum of solar and terrestrial radiation.

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

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

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

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.