Abbreviation for mean sea level.

See evaporation pan.

A radar which is used to obtain the azimuth elevation, and slant range of an airborne target.

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

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

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

Difference between the instantaneous wind velocity at a point and the mean wind velocity taken over a given time interval. Also called fluctuation velocity.

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 barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

The total amount of water transferred to the atmosphere by evapotranspiration.

The closeness of agreement among a number of consecutive output values measuring the same input value under the same operating conditions, approaching from the same direction. Usually measured as nonrepeatability but expressed as repeatability, a percenta ...

The process whereby a position on the scale of an instrument is identified with the magnitude of the signal (or input force) actuating the instrument.

The humidity transducinu element in a Diamond-Hinman radiosonde. Also called electrolytic strip.

A recording anemometer.

That portion of the record of a microbarograph between any two (or a specified small number) of successive crossings of the average pressure level (in the same direction). Analogous to microseism.

An instrument for measuring the pressure of the atmosphere. The two principle types are aneroid and mercurial.

A wooden enclosure about sixteen feet square and eight feet high with a precipitation gauge at its center. The function of the fence is to minimize eddies around the gauge and thus insure a catch that is representative of the actual rainfall or snowfall.

The distance or length of flow of the air past a point during a given interval of time.