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 ...

An increase in the central pressure of a pressure system; opposite of a deepening. More commonly applied to a low rather than a high.

The distance or length of flow of the air past a point during a given interval of time.

An instrument for measuring the intensity of direct solar radiation at normal incidence. See Angstrom compensation pyrheliometer, Eppley pyrheliometer, Michaelson actinograph. silver- disc pyrheliometer, spectropyrheliometer, waterflow pyrheliometer.

A rain gauge capable of measuring very small amounts of precipitation. Also called micropluviometer, trace recorder.

A type of cooling-power anemometer based upon the principle that the time constant of a thermometer is a function of its ventilation.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

The lowest value of a measured quality at which a sensor meets its accuracy specification.

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

An instrument used to determine atmospheric pressure or elevation by observing the boiling point of water or both liquids. The sensitivity of the hypsometer increases with decreasing pressure, making it more useful for high altitude work.

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged.

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

A type of pressure-plate anemometer in which the plate, restrained by a stiff spring, is held perpendicular to the wind. The wind-activated motion of the plate is measured electrically. The natural frequency of this system can be made high enough so that ...

A sunshine recorder of the type in which the time scale is supplied by a chronograph. It consists of two bulbs, one of which is blackened, which communicate through a glass tube of small diameter. The tube is partially filled with mercury and contains two ...

Literally "not wet", containing no liquid.

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

A description or explanation of the manner in which the height of the ceiling is determined, i.e. aircraft ceiling, balloon ceiling. estimated ceiling, indefinite ceiling, measured ceiling, precipitation ceiling.

An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen which graphs a record on a rotating drum. Sometimes called aneroidograph.

Line drawn through geographical points recording equal amounts of precipitation during a given time period or for a particular storm.