Clouds which cover between 6/10 and 9/10 of the sky. See Sky Terminology.

Radio Direction Finder.

For a given cloud or cloud laver. the lowest level in the atmosphere at which the air contains a perceptible quantity of cloud particles.

A general term to designate apparatus designed to observe the details of weather during thunderstorms.

A Sunshine recorder of the type in which the time scale is supplied by the motion of the sun. The instrument, which is pointed at the celestial pole, consists of a hemispherical mirror mounted externally on the optical axis of a camera. The lens of the ca ...

A wind vane used to obtain the horizontal and vertical components of the wind.

Automated Surface Observing System. A network of instrumented weather stations deployed primarily by the National Weather Service to make weather observations without operator involvement.

An area of low atmospheric pressure which has a closed circulation that is cyclonic (counterclockwise in northern hemisphere and clockwise in southern hemisphere).

An instrument for collecting liquid water from the atmosphere.

A small balloon used to determine the height of the cloud base. The height can be computed from the ascent velocity of the balloon and the time required for its disappearance into the cloud.

Same as atmometer.

A unit of energy per unit area commonly employed in radiation theory. Equal to one gram-calorie per square centimeter.

An instrument which indicates the presence of precipitation. The ombroscope consists of a heated, water-sensitive surface which indicates by mechanical or electrical techniques the occurrence of precipitation.

American Standard Code for Information Interchange. A standard code used to represent data using 8 bits (7 data bits and I parity bit) per character.

The rising of cold water from the deeper areas of the ocean to the surface. This phenomena often occurs along the California coast during the spring and summer.

An instrument for recording ocean waves. Most recorders are designed for recording wind waves, that is waves of periods up to about 25 seconds, but some are designed to record waves of longer periods such as tsunamis or tides.

A system of physical units based on the use of the centimeter, gram. and the second as elementary quantities of length. mass. and time.

Readily taking up and retaining moisture.

Same as constant-level balloon.

The process by which events in the real world are translated into machine-readable signals.