A type of instrument shelter. It is a wooden box painted white with double louvered sides and mounted on a stand four feet above the ground.

A combination cup anemometer and pressure-plate anemometer, consisting of an array of cups about a vertical axis of rotation, the free rotation of which is restricted by a suitable spring arrangement.

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

The study of waters (including oceans, lakes, and rivers) embracing either: (a) their physical characteristics, from the standpoint of the oceanographer or limnologist; or (b) the elements affecting safe navigation, from the point of view of the mariner. ...

Strong winds concentrated within a narrow band in the atmosphere. The jet stream often "steers" surface features such as front and low pressure systems.

A unit of luminous intensity of a light source.

Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

Facing away from the wind.

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

A special form of the aspiration psychrometer. developed by Assmann, in which the thermometric elements are well shielded from radiation. Psychrometric measurements may be taken with the instrument in the presence of direct solar radiation.

The direction, with respect to true north, from which the wind is blowing. Distinguish from magnetic wind direction. In all standard upper-air and surface weather observations, it is true wind direction that is reported.

A unit of power equal to one joule per second or 10' ergs per second.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

A unit of signaling speed representing the number of code elements sent per second; often, bits per second.

An evaluation, according to set procedures, of those weather elements which are most important for aircraft operations. Always includes cloud height or vertical visibility, sky cover, visibility, obstructions to vision, certain atmospheric phenomena, and ...

The boundary between the troposphere and stratosphere, usually characterized by an abrupt change in lapse rate. Its height varies from 10 to 20 km. Regions above the tropopause have greater atmospheric stability than regions below.

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

Thermometer used for measuring the lowest temperature attained during a given interval of time, for example, a day.

The measuring, transmitting, receiving, and indicating apparatus for obtaining the value of a quantity at a distance.