A line drawn through all points on a map having the same amount of cloudiness.

The intensity (flux per unit solid angle) of visible radiation weighted to take into account the variable response of the human eye as a function of the wavelength of light. Usually expressed in candles.

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

The difference between temperature measurements taken at two significant levels above the ground. Temperatures at 10 and 40 meters are commonly used.

Very small precipitation drops (diameters less than 0.5 mm) that appear to float with air currents while falling in an irregular path. Unlike fog droplets, drizzle falls to the ground.

NEXt Generation RADar. A NWS network of about 140 Doppler radars operating nationwide.

Abbreviation for the pressure, temperature, and humidity data obtained by a radiosonde observation.

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

See calorie.

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

The total infrared radiation emitted from the earth's surface. To be carefully distinguished from atmospheric radiation, effective terrestrial radiation, and insolation.

An automatic, recording cloud height indicator.

A power supply which achieves its output regulation by means of one or more active power handling devices which are alternately placed in the "off" or "on" states. It is more efficient than linear supplies which vary the conduction of power devices to ach ...

Snow shower, particularly of a very light and brief nature.

An inert gas. An element found in the atmosphere to the extent of only 0.000114 percent by volume. Its molecular weight is 83.7.

A small balloon, loaded with ballast and inflated so that it will explode at a predetermined altitude, which is attached to a larger balloon.

A instrument designed to study small fluctuations of some quantity. The microbarograph is an example of a recording pressure variometer.

The stage, on a fixed river gauge, corresponding to the top of the lowest banks within the reach for which the gauge is used as an index. Compare to flood stage.