The record of an aneroid barograph.

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

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.

A thermometer designed for use in measuring the temperature of sea water. One form consists of a mercury-in-glass thermometer protected by a perforated metal case. Another form consists of a mercury-in-glass thermometer surrounded by a metal case which fo ...

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 ...

A type of electrical thermometer consisting of two thermocouples which are series-connected with a potentiometer and a constant-temperature bath. One couple, called the reference junction, is placed in a constant-temperature bath, while the other is used ...

Binary Coded Decimal. A coding system in which each decimal digit from 0 to 9 is represented by a 4-digit binary number.

A conically shaped, copper rain gauge shield.

Automated Local Evaluation in Real Time. Network of automatic rain gauges that transmit via VHF radio link when precipitation occurs. Some sites are also equipped with other sensors such as temperature, wind, pressure, river stage or tide level. More info ...

The closeness of agreement among measurements of the same value of the same quantity where the individual measurements are made under different defined conditions, i.e. by different methods or with different measuring instruments.

A precipitation gauge consisting of a receiver in the shape of a funnel which empties into a bucket mounted upon a weighing mechanism. The weight of the catch is recorded as inches of precipitation.

Wind with a speed between 4 and 27 knots (4 and 31 mph); Beaufort scale numbers 2 through 6.

A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation. Elements evaluated include temperature, humidity, pressure, wind speed, and wind direction.

Same as wave pole.

A temperature-sensing element which converts thermal energy directly into electrical energy. In its basic form it consists of two dissimilar metallic conductors connected in a closed loop. Each junction forms a thermocouple. If one thermocouple is maintai ...

A chronograph used to make a time-record of certain measured meteorological elements. The most common type, the triple register, records wind direction and speed, duration of sunshine, and amount of rainfall (sensed respectively by a contact anemometer, M ...

An instrument, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

An increase or amplification. There are two general usages of the term in radar meteorology: (a) antenna gain (or gain factor) is the ratio of the power transmitted along the beam axis to that of an isotropic radiator transmitting the same total power; an ...

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

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.