Instrument for measuring the depth of water from precipitation that is assumed to be distributed over a horizontal, impervious surface and not subject to evaporation.

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

An aneroid barograph designed to record atmospheric pressure variations of very small magnitude.

The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

An instrument for measuring the relative speed of a fluid. It consists of a concentric pipe arrangement in which the inner pipe is open at one end and the outer pipe is perforated and closed at both ends. Each pipe is connected to a manometer. The unit is ...

The humidity transducinu element in a Diamond-Hinman radiosonde. Also called electrolytic strip.

A large plastic constant-level balloon for duration flying at very high altitudes.

The cardinal points of the compass, i.e. north, south, east, west.

A halo consisting of a faint white circle passing through the Sun and running parallel to the horizon for as much as 360

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

A rainbow seen in the spray of the ocean. It is optically the same phenomenon as the ordinary rainbow.

The sum of solar and terrestrial radiation.

A wind blowing in a direction opposite to the heading of a moving object, thus opposing the object's intended progress; the opposite of a tailwind.

An Instrument used to determine dew point.

An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium i ...

A counterclockwise change in wind direction. Backing winds with height are indicative of cold air advection (CAA).

Rain gauge which registers precipitation that is too light to be registered by ordinary recording of the depth of water from precipitation. Same as ombrometer.

See hurricane beacon.

An atmospheric phenomenon, other than clouds, which obscures a portion of the sky from the point of observation. Also called obscuration.

Root Mean Square. This notation is used frequently with error analysis. In that context, it is the square root of the arithmetic mean of the squares of the deviations of the individual calibration points from the theoretical or ideal response.