A device used by oceanographers to obtain subsurface samples of sea water. The "bottle" is lowered by wire, its valves open at both ends. It is then closed in situ by allowing a weight (called a messenger) to slide down the wire and strike the reversing m ...

The nautical mile is closely related to the geographical mile which is defined as the length of one minute of arc on the earth's equator. By international agreement, the nautical mile is now defined as 1852 meters.

Same as altimeter setting.

In general. the severe wind of an intense tropical cyclone (hurricane or typhoon). The term has no further technical connotation, but, unfortunately, is easily conftlsed with the strictly defined hurricane-force wind,

The smallest change in the environment that causes detectable change in the indication of an instrument. Compare to sensitivity.

Of or pertaining to rain.

A self-recording thermometer.

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

The height at which the maximum wind speed occurs, determined in a winds-aloft observation.

A type of directional antenna used on some types of radar and radio equipment consisting of an array of elemental, single- wire dipole antennas and reflectors.

An instrument for the measurement of the net flux of downward and upward total (solar and terrestrial) radiation through a horizontal surface.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

A device which surrounds a rain gauge and acts to maintain horizontal flow in the vicinity of the funnel so that the catch will not be influenced by eddies generated near the gauge. See Alter shield, Nipher shield, Wild fence.

An instrument for taking photographs of an image of the sun in monochromatic light.

A computed characteristic of a particular river basin, expressed as the time difference between the time-center of mass of rainfall and the time-center of mass of resulting runoff.

The distance that an observer can see vertically into a surface-based obscuring phenomenon such as fog, rain, or snow. The distance estimate must be based upon ceiling balloon ascensions or ceiling light projector measurements.

The condition of the atmosphere when the amount of water vapor present is the maximum possible at the existing temperature.

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

Precipitation of very small, white opaque particles of ice, fairly flat or elongated, with diameters less than 1 mm. The solid equivalent of drizzle.

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...