Name sometimes given to a transmissometer.

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

A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature.

A buoyant balloon rising freely in the atmosphere, as opposed to a captive balloon.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

The distance or length of flow of the air past a point during a given interval of time.

General term for any device that measures precipitation: principally a rain gauge or snow gauge.

A system of designating meteorological observing stations by number. established and administered by the World Meteorological Organization. Under this scheme, specified areas of the word are divided into "blocks" each bearing a two-number designator. Stat ...

An instrument for measuring radiant energy. It consists of an ether differential thermometer with blackened bulbs. One of the bulbs is exposed to the unknown radiation and the other to a black body source whose temperature can be varied. Equality of radia ...

See constant-level balloon.

Generally, the relative states of inflow, outflow, and storage of moisture over a given area of earth's surface.

Graduated fixed stake used in regions of abundant snowfall to facilitate the measurement of snow depth.

The value of atmospheric pressure to which the scale of a pressure altimeter is set so as to indicate airport elevation. The altimeter setting is included as part of an aviation weather observation.

Any quantity, such as force velocity, or acceleration, which has both magnitude and direction at each point in space, as opposed to scalar which has magnitude only. Such a quantity may be represented geometrically by an arrow of length proportional to its ...

Situated on the side from which the wind blows.

A diagram showing the intensity of the radiation field in all directions from a transmitting radio or radar antenna at a given distance from the antenna.

A unit of illuminance or illumination equal to one lumen per foot'. This is the illuminance provided by a light source of one candle at a distance of one foot.

The play or loose motion in an instrument due to the clearance existing between mechanically contacting parts.

A strong wind characterized by a sudden onset, a duration on the order of minutes, and a rather sudden decrease in speed.

A balloon used to carry a radiosonde aloft, considerably larger than pilot balloons or ceiling balloons.