A warm, dry wind on the lee side of a mountain range, the warmth and dryness due to adiabatic compression upon descent.

Same as geostrophic wind level.

The mean difference between the readings of a given instrument and those of a standard instrument.

A faintly-colored circular arc similar to a rainbow but formed on fog layers containing drops whose diameters are 100 microns or less. Also called mistbow, white rainbow.

An instrument for determining the degree of polarization of light. See photopolarimeter.

See stage.

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 ...

Same as recording rain gauge.

A thermometer, invented by James Six in 1782, which simultaneously indicates the maximum and minimum temperatures attained during a given interval of time. A U-tube min/max thermometer

A magnetometer of the electromagnetic type which is used to measure the horizontal intensity of the earth's magnetic field.

See constant-level balloon.

A systematic summary of the terms (inflow, outflow, and storage) of the storage equation as applied to the computation of soil-moisture changes, ground-water changes, etc. An evaluation of the hydrologic balance of an area. Also called basin accounting, w ...

Any conventional barometer fitted with an extended scale so that atmospheric pressure measurements may be made at both high and low altitudes.

The temperature at which all three phases of a substance can exist in equilibrium. This temperature occurs at only one pressure. The triple-point of water is 273.16 K and is the basis of the Kelvin scale.

Wind with a speed between 28 and 33 knots (32 and 38 mph); Beaufort scale number 7.

Lowest altitude in the atmosphere over a given location at which the air temperature is 0

The point (physical and/or electrical) where two distinct data processing elements meet.

Of equal or constant pressure, with respect to either space or time.

A type of cistern barometer in which the level of mercury in the cistern is adjusted to the zero point of the scale before each reading.

Temperature assumed by an unsaturated air parcel when brought adiabatically to a standard pressure (1,000 mb).