General name for an instrument designed to measure the vertical component of the wind speed. See anemoclinometer.

Same as water year.

Any wind blowing down an incline. If warm, it is a foehn. If cold, it may be a fall wind or a gravity wind.

Defect in the action of an aneroid barometer resulting in a sluggish adjustment of the index toward the correct reading when the barometer is subjected to a large and rapid change in pressure.

A photometric unit of illuminance or illumination equal to one lumen per square centimeter.

The time required for an instrument to register a designated percentage (frequently 90%) of a step change in the variable being measured.

Solar and terrestrial radiation directed downwards (towards the earth's surface); incoming radiation.

A calorimetric radiation instrument of historic interest used for the measurement of outgoing heat radiation from the earth during an interval of time. The time integration is performed by allowing the radiation to fall on an uninsulated vessel containing ...

The flux of visible radiation, so weighted as to account for the manner in which the response of the human eye varies with the Wavelength of radiation. The basic unit for luminous flux is the lumen,

The record or trace made by a microbarograph.

The outer, solid portion of the earth: the crust of the earth.

An instrument for measuring the extinction coefficient in water.

See captive balloon, ceiling balloon, constant-level balloon, free balloon, hurricane beacon, kytoon, Moby Dick balloon, pilot balloon, radiosonde balloon, rockoon, skyhook balloon, transosonde.

A thermopile used in some types of radiation instruments. See solarimeter.

The difference between the outgoing infrared terrestrial radiation of the earth's surface and the downcoming infrared counterradiation from the atmosphere.

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

Abbreviation for visual flight rules, but commonly used to refer to the relatively favorable weather and/or flight conditions to which these rules apply.

The closeness of agreement among a number of consecutive output values measuring the same input value under the same operating conditions, approaching from the same direction. Usually measured as nonrepeatability but expressed as repeatability, a percenta ...

A device for computing certain psychrometric data, usually the dew point and the relative humidity, from known values of the dry-bulb and wet-bulb temperatures and the atmospheric pressure. One type is the circular slide-rule form and, like the psychromet ...

A mercury-in-glass thermometer which records the temperature upon being inverted and retains its reading until being returned to the first position.