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

Same as recording rain gauge.

Same as geostrophic wind level.

The study of waters (including oceans, lakes, and rivers) embracing either: (a) their physical characteristics, from the standpoint of the oceanographer or limnologist; or (b) the elements affecting safe navigation, from the point of view of the mariner. ...

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

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

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 ...

See stage.

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

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 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 ...

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.

See constant-level balloon.

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.

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

Apparatus from which the nature and time of precipitation may be determined.

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