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

Same as parhelion.

A fabric cone attached to a metal ring and used to indicate wind direction. often at airfields.

The array of indicating marks and figure in relation to which the position of an index is observed, i.e. a scale plate on a recorder.

A liquid-in-glass thermometer which uses an organic substance such as alcohol as the thermometer liquid. This type of thermometer has a low freezing point and a high coefficient of expansion. It is less accurate, however, than a mercury thermometer.

A type of hygrometer which measures the water vapor content of the atmosphere by means of the absorption of vapor by a hygroscopic chemical.

A common type of terrestrial scintillation; shimmering over a hot surface (such as a roadway) on a quiet, cloudless. summer day.

The indicating part of an instrument. For example, the hand of a watch or the meniscus of a mercury column.

Precipitation caused by the ascent of moist air over an orographic barrier such as a Mountain range.

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.

A buoyant balloon kept from rising freely by means of a line secured to a point on the ground, as opposed to a free balloon. See kytoon.

Very small precipitation drops (diameters less than 0.5 mm) that appear to float with air currents while falling in an irregular path. Unlike fog droplets, drizzle falls to the ground.

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

A wave resulting from the action of wind on a water surface.

Water condensed onto objects at or near the ground, due to the fact that their temperatures have fallen below the dew point temperature of the surrounding air, but not below freezing.

A radiosonde which transmits the indication of the meteorological sensing elements in the form of a code consisting of combinations of dots and dashes.

Part of a computer word that has meaning in itself, often, a byte.

General term for an instrument used to make direct measurements of visual range or measurements of the physical characteristics of the atmosphere which determine the visible range.

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.

Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.