A systematic observational error due to the characteristics of the observer. The uncertainty in a reading made by an observer may be acertained by a statistical analysis of his or her readings.

The measuring, transmitting, receiving, and indicating apparatus for obtaining the value of a quantity at a distance.

A radar term for a single pulse of radio energy.

One of several constant-pressure levels in the atmosphere for which a complete evaluation of data derived from upper air observations is required.

A protective coating applied to circuits.

Instrument for measuring the intensity of radiant energy. Its principle is based on the variation of electrical resistance, with the incoming radiation, of one or both the metallic strips which the instrument comprises.

Wind with a speed between 41 and 47 knots (47 and 54 mph); Beaufort scale number 9.

The water volume within a specified portion of a stream channel.

February 2nd. In American folklore, a day that is popularly supposed to provide the key to the weather for the remainder of the winter. Specifically, if the ground-hog upon emerging from its hole casts a shadow, it will return underground, thereby forebod ...

Any source of radiant energy, especially electromagnetic energy.

An instrument resulting from the combination of a thermograph and a hygrograph and furnishing, on the same chart, simultaneous time recording of ambient temperature and humidity.

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

Same as ceiling light.

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

Reduction of visibility by strong winds blowing across dry ground with little or no vegetation. Visibilities of 1/8 mile or less over a widespread area are criteria for a Blowing Dust Advisory.

An instrument for measuring snow hardness in terms of the resistance of snow to the pressure exerted by a disk attached to a spring-loaded rod, a gauge calibrated in pounds per square inch registers the amount of resistance. See Canadian hardness gauge.

The size of the area comprising a watershed or river basin. Also called catchment area.

A temperature telemeter.

General term for any device that measures precipitation: principally a rain gauge or snow gauge.

An instrument which measures the rate of evapotranspiration. It consists of a vegetation soil tank so designed that all water added to the tank and all water left after evapotranspiration can be measured.