The wind speed and direction at various levels in the atmosphere above the level reached by surface weather observations.

A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

In general, solar radiation received at the earth's surface. Contracted from incoming solar radiation.

A type of electrical thermometer consisting of two thermocouples which are series-connected with a potentiometer and a constant-temperature bath. One couple, called the reference junction, is placed in a constant-temperature bath, while the other is used ...

A system of physical units based upon the use of the meter, the metric ton (106 grams), and the second as elementary quantities of length, mass, and time, respectively.

Facing away from the wind.

The atmospheric pressure computed using station elevation as the reference datum level. Station pressure is usually the base value from which sea level pressure and altimeter setting are determined.

The difference between downward and upward (total) radiation; net flux of all radiation.

Same as freezing point.

An instrument for the measurement of the rate of ice accretion on an unheated body.

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

A measure of the degree to which the weather or climate of a region is favorable to the process of evaporation. Usually considered to be the rate of evaporation. under existing atmospheric conditions, from a surface of water which is chemically pure and h ...

Meteorological information issued by a watch office concerning the occurrence or forecast of weather phenomena which may affect the safety of aircraft operations.

A modification of the dew cell used in radiosonde equipment.

(1) The ratio of the speeds of a chemical reaction at two temperatures differing by 10

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.

Wind with a speed between 28 and 33 knots (32 and 38 mph); Beaufort scale number 7.

Precipitation composed of white or translucent ice crystals, chiefly in complex branched hexagonal forms.

An instrument for photographing the corona and prominences of the sun at times other than at solar eclipse.