The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

Same as river gauge.

An instrument for measuring the intensity of light or the relative intensity of a pair of lights. Also called an illuminometer. If the instrument is designed to measure the intensity of light as a function of wavelength, it is called a spectrophotometer. ...

Anemometer whicb measures wind speed by measuring the degree of cooling of a metal wire heated by an electric current. A type of cooling power anemometer.

Forecasting weather by the use of numerical models, run on high speed computers. Most of the NWP for the National Weather Service is done at the National Centers for Environmental Prediction (NCEP).

An empirical curve relating stream discharge or stage at a point on a stream to discharge or stage at one or more upstream points and, possibly. to other parameters. Also called stage relation.

A measure of luminous flux remaining in a light beam after it has passed through a specified distance of the atmosphere.

An instrument for measuring the pressure of the atmosphere. The two principle types are aneroid and mercurial.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

The most common of the principal rainbow phenomena, which appears as an arc of about 42

Abbreviation for mean sea level.

A unit of mass numerically equal to the molecular weight of the substance. The gram-mote or gram-molecule is the mass in grams numerically equal to the molecular weight, i.e. a gram-mole of oxygen is 32 grams.

An elongated area of relatively high pressure. Usually associated with and most clearly identified as an area of maximum anticyclonic curvature of the wind flow. The opposite of a trough.

Same as balloon cover.

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

The upper surface of a column of liquid.

To free something from the binding action of ice by warming it to a temperature above the melting point of ice. Also, a warm spell when ice and snow melt.

Sir Napier Shaw's name for the approximate absolute temperature scale,

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.