Abbreviation for precipitation-evaporation quotient.

Abbreviation for the pressure, temperature, and humidity data obtained by a radiosonde observation.

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

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

United Kingdom forecast model. (Available via AccuWeather.com Professional.)

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 ...

A radiosonde equipped to measure temperature only.

A method of winds aloft observation essentially the same as a pilot balloon observation except the height data is derived from the radiosonde observation rather than from assumed ascension rates.

An absolute temperature scale with the ice point of pure water defined as 273.16 K. The size of the degree is the same as on the Celsius scale, and the zero point is absolute zero.

A unit of luminance (or brightness) equal to 1/6 candles per square centimeter.

Apparatus in which radar techniques are used to determine the range, elevation, and azimuth of a balloonborne target, to computer upper-air wind data. It is a type of rawin system.

A hydrometeor consisting of a visible aggregate of minute water and/or ice particles in the atmosphere above the earth's surface. Cloud differs from fog only in that the latter is, by definition, in contact with the earth's surface.

The energy of any type of electromagnetic radiation. Also called radiation.

The difference between the true value of some quantity and its observed value. Every observation is subject to certain errors. Systematic errors affect the whole of a series of observations in nearly the same way. For example, the scale of an instrument m ...

Name applied to a class of instruments which measure the liquid content of the atmosphere.

An atmospheric phenomenon, other than clouds, which obscures a portion of the sky from the point of observation. Also called obscuration.

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

Any soft, gentle breeze.

The source of illumination for an antenna reflector. Also called antenna feed.

A polariscope consisting of a specially constructed double plate polarizer and a tourmaline plate analyzer. Polarized light passing through the instrument is indicated by the presence of parallel colored fringes, while unpolarized light results in a unifo ...