check chamber-A chamber use to check the sensing elements of radiosonde equipment.

An instrument, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

An instrument, located at the surface observing station, which is used to record the data presented by a radiosonde aloft.

The difference between the true value of some quantity and its observed value. Every observation is subject to certain errors. Systematic errors affect the whole of a series of observations in nearly the same way. For example, the scale of an instrument m ...

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

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.

One of several constant-pressure levels in the atmosphere for which a complete evaluation of data derived from upper air observations is required.

Either of two colored luminous spots that appear at points 22

A definite portion of a stream channel, commonly taken between two gauging stations, but may be taken between any two specified points.

A small pointer extending downward from the top of the cistern of a Fortin barometer. The level of the mercury in the cistern is adjusted so that it just comes in contact with the end of the pointer, thus setting the zero of the barometric scale.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

Anemometer which measures wind speed by the speed of rotation of 3 or 4 hemispherical or conical cups, each fixed to the end of a horizontal arm projecting from a vertical axis. See condenser-discharge anemometer, contact anemometer. Compare to bridled-cu ...

Snow shower, particularly of a very light and brief nature.

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

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.

An inert gas. An element found in the atmosphere to the extent of only 0.000114 percent by volume. Its molecular weight is 83.7.

See radiation shield.

An Instrument used to determine dew point.

The value of the quantity measured, as indicated or otherwise provided by a measuring instrument.

A reversing thermometer (for seawater temperature) which is not protected against hydrostatic pressure. The mercury bulb is therefore squeezed, and the amount of mercury broken off on reversal is a function of both temperature and of hydrostatic pressure.