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 hydrometeor consisting of a visible aggregate of minute water and/or ice particles in the atmosphere above the earth's surface. Cloud differs from fog only in that the latter is, by definition, in contact with the earth's surface.

A pyrheliometer of the thermoelectric type. Radiation is allowed to fall on two concentric silver rings, the outer covered with magnesium oxide and the inner covered with lamp black. A system of thermocouples (thermopile) is used to measure the temperatur ...

A sounding balloon which, when operationally inflated, resembles an inverted teardrop.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

A measure of the amount of "spin" (or rotation) in the atmosphere.

Same as pitot tube.

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

An instrument which automatically records the voltage applied to it, as a function of time.

The process in which incident radiation is retained by a substance. A further process always results from absorption.

Conditions to which a device is subjected, not including the variable measured by the device. See normal operating conditions, reference operating conditions.

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

Same as humidity strip.

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

Apparatus in which radar techniques are used to determine the range, elevation, and azimuth of a balloonborne target, to computer upper-air wind data. It is a type of rawin system.

Programs or instructions which are stored in readonly memory.

To free something from the binding action of ice by warming it to a temperature above the melting point of ice. Also, a warm spell when ice and snow melt.

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