That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

That horizontal wind velocity at which the Coriolis acceleration exactly balances the horizontal pressure force. It is directed along contour lines or isobars.

A cup anemometer with its shaft mechanically coupled to a magneto.

An anemometer which measures wind speed by means of the properties of wind-borne sound waves. It operates on the principle that the propagation velocity of a sound wave in a moving medium is equal to the velocity of sound with respect to the medium plus t ...

A calorimetric radiation instrument of historic interest used for the measurement of outgoing heat radiation from the earth during an interval of time. The time integration is performed by allowing the radiation to fall on an uninsulated vessel containing ...

A device which automatically records the water equivalent of snow on a given surface as a function of time. A small sample of a radioactive salt is placed in the ground in a shielded collimator which directs a beam of radioactive particles upwards. A Geig ...

A temperature telemeter.

A type of wind vane having a split or V-shaped tail. The apex orients itself to the direction of the wind.

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

A large plastic constant-level balloon for duration flying (in excess of 24 hours) at altitudes above 40,000 feet, used for the determination of wind fields and the measurement of upper atmospheric parameters.

Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

Radiation with wavelengths greater than 4 microns. (In meteorology, same as infrared radiation.)

A unit measure of electrical conduction. The facility with which a substance conducts electricity, as represented by the current density per unit electrical-potential gradient in the direction of flow. Electrical conductivity is the reciprocal of electric ...

Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.

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

A wind blowing in a direction perpendicular to the course of a moving object.

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.

Same as contact anemometer.

A line of equal or constant temperature.

A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.