meter-An instrument for measuring the transmissivity of the atmosphere; a type of transmissometer. It consists of a constant- intensity collimated light source located at a suitable distance from a photoelectric cell. Variation in the turbidity of the atm ...

An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium i ...

force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

A thermometer using transducing elements which deform with temperature. Examples are the bimetallic thermometer and the Bourdon tube type of thennometer.

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

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 part of a measuring instrument which responds directly to changes in the environment.

The ratio of the actual amount of water evaporated into the atmosphere to the evaporative power. Also called relative evaporation.

The process by which one object becomes adhered to another by the binding action of ice.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

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

A recording variometer.

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged.

A reflecting type telescope with a 45

Conditions to which a device is subjected, not including the variable measured by the device. See normal operating conditions, reference operating conditions.

The true freezing point of water. The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere.

That stage, on a fixed river gauge, at which overflow of the natural banks of the stream begins to cause damage in any portion of the reach for which the gauge is used as an index.

A common type of liquid-inglass thermometer, used, in meteorology, in psychrometers and as a maximum thermometer.

A conductor or system of conductors for radiating and/or receiving radio energy. Also called aerial.