The record or trace made by a microbarograph.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

A clockwise change in wind direction. Veering winds with height are indicative of warm air advection (WAA).

Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

A recording weight barometer.

An Instrument used to determine dew point.

See photometer.

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

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

A basic equation in night visual range theory, relating the illuminance of a point source of light to distance and the transmissivity of the atmosphere.

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

The portion of the strearnflow during any month or year derived from precipitation in previous months or years.

An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states. Thermometers may be classified into types according to their construction; deformation thermometer, electrical t ...

A thermodynamic change of state in a system in which there is no transfer of heat or mass across the boundaries of the system. In an adiabatic process, compression always results in warming, expansion in cooling. Compare to diabatic process.

A momentary decrease in the speed of the wind.

An instrument which automatically records the measurement of two or more meteorological elements.

The number of cycles per second between the limits of a frequency band.

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

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

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...