See standard atmosphere.

Same as an upper air observation, but commonly used to refer to a single complete radiosonde observation.

The physical exposure of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and not always correctable. The purpose of the instrument shelter is to prov ...

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.

The ratio of the actual amount of water evaporated into the atmosphere to the evaporative power. Also called relative evaporation.

A unit of luminance or brightness equal to 1/d candles per foot'.

See approximate absolute temperature scale, Celsius temperature scale, centigrade temperature scale, Fahrenheit temperature scale, Kelvin temperature scale, Rankine temperature scale, Reaumur temperature scale,

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

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

A reversing thermometer which is encased in a strong glass outer shell that protects it against hydrostatic pressure. Compare to unprotected thermometer.

The unit of speed in the nautical system; one nautical mile per hour. It is equal to 1.1508 statute miles per hour or 0.5144 meters per second.

An instrument for measuring the extinction coefficient in water.

An instrument for measuring the relative speed of a fluid. It consists of a concentric pipe arrangement in which the inner pipe is open at one end and the outer pipe is perforated and closed at both ends. Each pipe is connected to a manometer. The unit is ...

The maximum rate at which precipitation can pass through the surface into the soil, for a given soil in a given condition.

A radar which is used to obtain the azimuth elevation, and slant range of an airborne target.

The effect upon the measurement of rainfall caused by the presence of the rain gauge.

A recording siphon barometer.

Cathode Ray Tube. A display element, consisting of a vacuum tube and screen, used with computers.

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

A unit of energy per unit area commonly employed in radiation theory. Equal to one gram-calorie per square centimeter.