A radiosonde which is dropped by parachute from an aircraft for the purpose of obtaining soundings of the atmosphere below.

A temperature-sensing element which converts thermal energy directly into electrical energy. In its basic form it consists of two dissimilar metallic conductors connected in a closed loop. Each junction forms a thermocouple. If one thermocouple is maintai ...

A refraction phenomenon similar to a parahelion, but occurring generally at a distance of 120

Contraction for pilot balloon observation.

film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...

A local variation of the wind vector or any of its components in a given direction.

A continuous-recording barometer.

Same as mercury barometer.

The state of the atmosphere, mainly with respect to its effects upon life and human activities. As distinguished from climate, weather consists of the short-term (minutes to months) variations of the atmosphere.

The most common of the principal rainbow phenomena, which appears as an arc of about 42

An evaporation pan in which the evaporation is measured from water in a pan floating in a larger body of water.

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.

A temperature scale based on absolute zero. Same as Kelvin temperature scale.

A set of weekly colored rainbow arcs sometimes discernable inside a primary rainbow.

An early and once universal name for the mercury barometer.

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

The mass density of a parcel of air expressed in units of mass per volume.

An instrument which indicates the presence of dust particles in the atmosphere. Also spelled coniscope.

Abbreviation for precipitation effectiveness index.

Instrument used to measure the amount of water evaporated from the soil surface during a given time interval.