Electromagnetic radiation of very short wavelength. lying within the wavelength interval of 0.1 to 1.5 angstroms (between gamma rays and ultraviolet radiation). X-rays penetrate various thicknesses of all solids, and they act on photographic plates in the ...

Any source of radiant energy, especially electromagnetic energy.

Abbreviation for precipitation-evaporation quotient.

A thermodynamic change of state in a system in which there is no transfer of heat or mass across the boundaries of the system. In an adiabatic process, compression always results in warming, expansion in cooling. Compare to diabatic process.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

An instrument which records the duration of sunshine and gives a quantitative measure of the amount of sunshine by the action of the sun's rays upon blueprint paper. A type of sunshine recorder.

An instrument for taking photographs of an image of the sun in monochromatic light.

check chamber-A chamber use to check the sensing elements of radiosonde equipment.

A constant which describes the performance of a wind vane in response to a step change in wind direction. It is calculated from the relative amount of overshoot on two successive swings (half cycles) of a decaying oscillation. This specification is dimens ...

See bimetallic thermometer.

A instrument designed to study small fluctuations of some quantity. The microbarograph is an example of a recording pressure variometer.

A rainbow formed by light rays which have been reflected from an extended water surface. Not to be confused with a reflected rainbow whose image may be seen in a still body of water. The center of a reflection rainbow is at the same elevation as the sun b ...

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.

Routine broadcast of meteorological information for aircraft in flight.

An aviation weather forecast for a specific flight.

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

Readily taking up and retaining moisture.

An evaluation of upper air temperature, pressure, and humidity from radio signals received from a balloon- borne radiosonde.

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 rain gauge which indicates but does not record the amount of precipitation captured.