An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

Wind with a speed between 4 and 27 knots (4 and 31 mph); Beaufort scale numbers 2 through 6.

A recording hair hygrometer.

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 rain gauge which is placed under trees or foliage to determine the rainfall in that location. By comparing this catch with that from a rain gauge set in the open. the amount of rainfall which has been intercepted by foliage can be determined.

Difference between the temperatures of the dry-bulb and the wet-bulb thermometers of a psychrometer.

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 ...

An automatic, recording cloud height indicator.

The interval between the lower and upper measuring limits of an instrument, i.e. a thermometer with a range of -35 to 50

A basic equation in daytime visual range theory, relating the apparent luminance of a distant black object, the apparent luminance of the background sky above the horizon, and the extinction coefficient of the atmosphere, or the air layer near the ground. ...

General term for any device that measures precipitation: principally a rain gauge or snow gauge.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

A balloon used to carry a radiosonde aloft, considerably larger than pilot balloons or ceiling balloons.

A sudden brief increase in the speed of the wind, followed by a lull or slackening. Compare to peak gust.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

Wind with a speed between 56 and 63 knots (64 and 72 mph); Beaufort scale number 11.

The atmospheric pressure at the level of the barometer. May or may not be the same as station pressure.

A conically shaped, copper rain gauge shield.

A device for obtaining a continuous record of stage at a point on a stream. The most common recorders consist of a float-actuated pen which traces a record on a clock driven chart.

Same as geostrophic wind level.