Liquid water at temperatures colder than freezing.

An approximation to the complete equations describing atmospheric motion in which only the terms most important for the growth and decay of synoptic scale extratropical weather systems (i.e., the large areas of high and low pressure seen on weather maps) ...

Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

In folklore, a name for rain.

A clockwise change in wind direction. Veering winds with height are indicative of warm air advection (WAA).

General name for a type of instrument which measures the inclination of the wind to the horizontal plane. See bivane.

Same as water year.

The correction applied to an instrument to account for the effect of temperature upon its response characteristics.

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

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

An estimate of the temperature of an incandescent body, determined by observing the wavelength at which it is emitting with peak intensity (its color) and using that wavelength in Wien's law.

An automatic, recording cloud height indicator.

A radiosonde whose carrier wave is switched on and off in such a manner that the interval of time between the transmission of signals if a function of the magnitude of the meteorological elements being measured.

A thermometer based upon the principle that the velocity of a sound wave is a function of the temperature of the medium through which it passes. Sonic thermometers possess very short time-constants and eliminate radiation error.

The maximum difference in output for any given input (within the specified range) when the value is approached first with increasing, and then with decreasing, input signals. Caused by energy absorption in the elements of the measuring instrument. Usually ...

In general. the severe wind of an intense tropical cyclone (hurricane or typhoon). The term has no further technical connotation, but, unfortunately, is easily conftlsed with the strictly defined hurricane-force wind,

The total infrared radiation emitted from the earth's surface. To be carefully distinguished from atmospheric radiation, effective terrestrial radiation, and insolation.

A direct-vision nephoscope which is constructed in the following manner: a comb consisting of a crosspiece containing equispaced vertical rods is attached to one end of a column eight to ten feet long and is supported on a mounting that is free to rotate ...

A radar which is used to obtain the azimuth elevation, and slant range of an airborne target.