A graphical aid used in the reduction of data from a winds aloft observation.

Name sometimes used in place of pyranometer as a generic term.

Abbreviation for mean sea level.

The physical exposure of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and not always correctable. The purpose of the instrument shelter is to prov ...

The rate of decrease of temperature with height when unsaturated air is lifted adiabatically (without exchange of heat with its surroundings). The decrease is due to expansion as the air is lifted to a lower pressure.

An instrument which measures the rate of evapotranspiration. It consists of a vegetation soil tank so designed that all water added to the tank and all water left after evapotranspiration can be measured.

Automated Local Evaluation in Real Time. Network of automatic rain gauges that transmit via VHF radio link when precipitation occurs. Some sites are also equipped with other sensors such as temperature, wind, pressure, river stage or tide level. More info ...

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

The measurement and computation of wind speeds and directions at various levels above the surface of the earth. Methods include pilot balloon observations, rabals, rawin or rawinsonde observations, radar tracking, or acoustic sounding.

Abbreviation for binary digit. The smallest unit of information, equal to one binary decision, i.e. 1/0, on/off, yes/no.

The general term for dry atmospheric suspensoids, including dust, haze, smoke. and sand. Compare to hydrometeor.

Name sometimes given to a transmissometer.

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

Operation mode of a communication circuit in which one end can only transmit and the other end can only receive.

Line drawn through geographical points recording equal amounts of precipitation during a given time period or for a particular storm.

A small balloon whose ascent is followed by a theodolite in order to obtain data for the computation of winds aloft.

A fabric cone attached to a metal ring and used to indicate wind direction. often at airfields.

The older name for the Celsius temperature scale. Officially abandoned by international agreement in 1948, but still in common use.

Same as instrument shelter.

An accumulation of granular ice tufts on the windward sides of exposed objects that is formed from supercooled fog or cloud and built out directly against the wind.