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.

A general term for instruments designed to measure the speed or force of the wind.

A rain gauge capable of measuring very small amounts of precipitation. Also called micropluviometer, trace recorder.

The correctable part of the inaccuracy of an instrument.

A numbering system using a base number of 2 and having only two digits: 0 and 1. The fundamental system of representing information with electrical pulses.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

An instrument of the aspiration condenser type which measures the concentration and mobility of small ions.

Wind with a speed between 11 and 16 knots (13 and 18 mph); Beaufort scale number 4.

A mercury-in-glass thermometer which records the temperature upon being inverted and retains its reading until being returned to the first position.

A c.g.s. (centimeter-gram-second) unit of mass. Originally defined as the mass of 1 cubic centimeter of water at 4

Electromagnetic radiation lying in the wavelength interval between 0.8 micron and I millimeter. At the lower limit of this interval, the infrared radiation spectrum is bounded by visible radiation, while on its upper limit it is bounded by microwave radia ...

A wind blowing in a direction opposite to the heading of a moving object, thus opposing the object's intended progress; the opposite of a tailwind.

See radiosonde commutator.

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

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.

A fixed-length group of bits representing the large data element handled as a unit by a computer. Word length is determined by the capacity of the CPU registers.

A seasonal wind of persistent direction, characterized by a pronounced change in direction between seasons.

A photoelectric spectrophotometer which is used in the determination of the ozone content of the atmosphere.

A curve showing the variation of temperature with height in the free air. See lapse rate.

A rainbow formed by light rays which have been reflected from an extended water surface. Not to be confused with a reflected rainbow whose image may be seen in a still body of water. The center of a reflection rainbow is at the same elevation as the sun b ...