See constant-level balloon.

Same as balloon cover.

Not a linear function of the relevant variables.

Navy Operational Global Atmospheric Prediction System. A global meteorological model operated by the Department of Defense.

The cardinal points of the compass, i.e. north, south, east, west.

A device used on certain types of instruments to prevent unwanted radiation from affecting the measurement of a quantity. Also called solar radiation shield.

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

A recording hair hygrometer.

General name for an instrument which measures the earth's magnetic field intensity.

A halo phenomenon consisting of a horizontal circle passing through the moon, corresponding to the parhelic circle through the sun. Produced by reflection of moonlight from ice crystals.

A type of anemometer in which the rotation of an element serves to measure the wind. Rotation anemometers are divided into two classes; those in which the axis of rotation is horizontal, such as the windmill anemometer, and those in which the axis of rota ...

Snow shower, particularly of a very light and brief nature.

Anemometer which generates an electrical contact output with a frequency proportional to wind speed.

The difference between the air temperature and the dew-point. Also called dew-point deficit, dew-point depression.

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

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

A box-like structure designed to protect certain meteorological instruments from exposure to direct sunlight, precipitation, and condensation, while at the same time providing adequate ventilation. Instrument shelters are painted white, have louvered side ...

Same as rain gauge.

An evaluation of upper air temperature, pressure, and humidity from radio signals received from a balloon- borne radiosonde.

A type of cloud height indicator which uses a searchlight to project vertically a narrow beam of light onto the cloud base. The height of the cloud is determined using a clinometer, located at a known distance from the ceiling light, to measure the angle ...