An instrument used for the measurement of the reflecting, power (the albedo) of a surface. A pyranometer adapted for the measurement of radiation reflected from the earth's surface is sometimes employed as an albedometer.

A constant which describes the performance of a wind vane in response to a step change in wind direction. It is calculated from the relative amount of overshoot on two successive swings (half cycles) of a decaying oscillation. This specification is dimens ...

See evaporation pan.

A buoyant balloon rising freely in the atmosphere, as opposed to a captive balloon.

A unit that represents one degree of deviation from a reference point in the mean daily outdoor temperature (usually 65

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

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

A self-recording thermometer.

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

A unit of pressure which directly expresses the force exerted by the atmosphere. Equal to 1000 dynes/cm2 or 100 pascals.

A hydrostatic principle that pressure supplied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the containing vessel.

See feed.

See hook gauge.

A line drawn through all points on a map having the same amount of cloudiness.

In physics, any process in which the flux density (or power, amplitude, intensity, illuminance, etc.) of a "parallel beam" of energy decreases with increasing distance from the source. Attenuation is always due to the action of the transmitting medium its ...

A rocket designed primarily for routine upper air observations in the lower 250,000 feet of the atmosphere, especially that portion inaccessible to balloons (above 100,000 feet).

A recording magnetometer.

An instrument for measuring differences of electric potential.

Formation of a single water drop by the union of two or more colliding drops.

A wind vane used to obtain the horizontal and vertical components of the wind.