See gain.

A unit of heat originally defined as the amount of heat required to raise the temperature of water through one degree centigrade (the gram-calorie or small calorie), but this proved to be insufficiently precise. The 15

An instrument for measuring the relative speed of a fluid. It consists of a concentric pipe arrangement in which the inner pipe is open at one end and the outer pipe is perforated and closed at both ends. Each pipe is connected to a manometer. The unit is ...

check chamber-A chamber use to check the sensing elements of radiosonde equipment.

An anemometer which derives wind speed from measurements of dynamic wind pressures. Wind blowing into a tube develops a pressure greater than the static pressure, while wind blowing across a tube develops a pressure less than the static. This pressure dif ...

A recording anemoclinometer.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

The outer, solid portion of the earth: the crust of the earth.

Wind with a speed between 56 and 63 knots (64 and 72 mph); Beaufort scale number 11.

In a system of moist air, the dimensionless ratio of the mass of water vapor to the mass of dry air. For many purposes, the mixing ratio may be approximated by the specific humidity.

A recording anemometer.

The process by which water in plants is transferred as water vapor to the atmosphere. Also, the amount of water so transferred.

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

The direction from which the wind is blowing, measured in points of the compass or in azimuth degrees.

Dihydrogen oxide, molecular formula H2O.

Solar radiation scattered by particles in the atmosphere.

A record obtained from a meteorograph. A chart in which meteorological variables are plotted against time.

A modification of the dew cell used in radiosonde equipment.

See bimetallic thermometer.

The total luminous flux received on a unit area of a given real or imaginary surface, expressed in such units as the foot-candle, lux, or phot.