The value of atmospheric pressure to which the scale of a pressure altimeter is set so as to indicate airport elevation. The altimeter setting is included as part of an aviation weather observation.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

A device which automatically records the water equivalent of snow on a given surface as a function of time. A small sample of a radioactive salt is placed in the ground in a shielded collimator which directs a beam of radioactive particles upwards. A Geig ...

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 ...

A self-recording instrument used on aircraft for the simultaneous recording of atmospheric pressure, temperature, and humidity.

Tables prepared from the psychrometric formula and used to obtain vapor pressure, relative humidity, and dew point from values of wet-bulb and dry-bulb temperatures.

That portion of the atmosphere which is above the lower troposphere. Generally applied to levels above 850 mb.

An instrument designed to record the duration of sunshine at a given location without regard to intensity. See Campbell- Stokes recorder, Jordan sunshine recorder, Marvin sunshine recorder, Pers sunshine recorder.

Generally, the relative states of inflow, outflow, and storage of moisture over a given area of earth's surface.

Infrared radiation emitted by or being propagated through the atmosphere.

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. ...

An instrument used for the determination of the electrical conductivity of the atmosphere.

Precipitation of white, opaque, spherical or conical ice particles that are crisp and easily crushed and that have diameters of 2 to 5 mm.

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

See gust and peak gust.

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 ...

An Instrument used to determine dew point.

Abbreviation for the pressure, temperature, and humidity data obtained by a radiosonde observation.

A class of instruments employed to determine the electric potential at a point in the atmosphere, and ultimately the atmospheric electric field.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.