Downward scattered and reflected solar radiation, coming from the whole hemisphere with the exception of the solid angle of the sun's disc on a surface perpendicular to the axis of this cone.

In meteorology, an area of low pressure; a low or trough.

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

An anemometer which measures wind speed in terms of the drag which the wind exerts on a solid body. See bridled-cup anemometer, normal-plate anemometer, pendulum anemometer.

Companion to the wet-bulb thermometer in a psychrometer. Used to measure ambient air temperature.

A high-altitude sounding system consisting of a small solid- propellant research rocket carried aloft by a large plastic balloon. The rocket is fired near the maximum altitude of the balloon flight.

A particular pattern of snow sampler having an internal diameter of 1.485 inches so that each inch of water in the sample weighs one ounce.

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

Read Only Memory. A memory that cannot be altered in normal use of a computer, Usually used to store information permanently, such as firmware programs.

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.

Same as an upper air observation, but commonly used to refer to a single complete radiosonde observation.

A measure of the intrinsic luminous intensity emitted by a source in a given direction. Luminance is a measure only of light. The comparable term for electromagnetic radiation in general is radiance.

General term for any device that measures precipitation: principally a rain gauge or snow gauge.

meter-An instrument for measuring the transmissivity of the atmosphere; a type of transmissometer. It consists of a constant- intensity collimated light source located at a suitable distance from a photoelectric cell. Variation in the turbidity of the atm ...

A line drawn through geographical points having the same pluvial index.

A technique for making winds aloft observations in which two theodolites located at either end of a baseline follow the ascent of a pilot balloon. Synchronous measurements of the elevation and azimuth angles of the balloon. taken at periodic intervals, pe ...

The process by which water in plants is transferred as water vapor to the atmosphere. Also, the amount of water so transferred.

A small, limited-capacity central processing unit contained entirely on one semiconductor chip.

A measure of luminous flux remaining in a light beam after it has passed through a specified distance of the atmosphere.

See calorie.