An anemometer which derives wind speed from measurements of dynamic wind pressures. Wind blowing into a tube develops a pressure greater than the static pressure, while wind blowing across a tube develops a pressure less than the static. This pressure dif ...

See gust and peak gust.

A severe weather condition characterized by low temperatures and strong winds bearing a great amount of snow, either falling or picked up from the ground.

A line drawn through geographical points where a given seasonal biological event occurs on the same date.

An instrument for photographing the corona and prominences of the sun at times other than at solar eclipse.

An instrument which measures combined direct solar radiation and diffuse sky radiation. See pyrheliometer, Robitzsch actinograph. solarimeter. See also albedometer.

A subtle, diumal component of the wind velocity leading to a diumal shift of the wind or turning of the wind with the sun, produced bv the east-to-west progression of daytime surface heating.

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.

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.

See calorie.

Apparatus in which radar techniques are used to determine the range, elevation, and azimuth of a balloonborne target, to computer upper-air wind data. It is a type of rawin system.

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 ...

A hydrostatic principle that pressure supplied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the containing vessel.

A mercury barometer in which the tube is U-shaped and the upper and lower mercury surfaces have the same diameter.

Any device or instrument for measuring salinity, especially one based on electrical conductivity methods.

Contraction for pilot balloon observation.

A cone-tipped metal rod designed to be driven downward into deposited snow or firn. The measured amount of force required to drive the rod a given distance is an indication of the physical properties of the snow or firn.

The process in which incident radiation is retained by a substance. A further process always results from absorption.

variable audio-modulated radiosonde developed at the Bureau of Standards and used by the United States weather services.

A weakly colored lunar halo identical in form and optical origin to the solar parhelion.