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

meter-An instrument for measuring the transmissivity of the atmosphere; a type of transmissometer. It consists of a constant- intensity collimated light source located at a suitable distance from a photoelectric cell. Variation in the turbidity of the atm ...

In general, any self-recording instrument carried aloft by any means to obtain meteorological data.

Any one of a family of circular arcs consisting of concentric colored bands, arranged from red on the inside to blue on the outside, which may be seen on a "sheet" of water drops (rain, fog, spray). The most common of the many possible is the primary rain ...

Operation mode of a communication circuit in which each end can transmit and receive, but not simultaneously.

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.

The total area drained by a river and its tributaries. Same as watershed.

A mercury barometer which measures atmospheric pressure by weighing the mercury in the column or cistern.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

A form of psychrometer with wet-bulb and dry-bulb thermometers mounted on opposite sides of a specialty designed graph of the psychrometric tables. It is so arranged that the intersections of two curves determined by the wet-bulb and dry-bulb readings -yi ...

Pyrheliometer based on the comparison of the heating of two identical metal strips, one exposed to radiation, the other to a joule effect.

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.

A thermometer which uses a transducing element whose element proper-ties are a function of its thermal state. Common meteorological examples of such thermometers are the resistance thermometer and the thermoelectric thermometer.

Same as mercury barometer.

A line drawn through geographical points having the same duration of sunshine (or other function of solar radiation) during a given interval of time.

Navy Operational Global Atmospheric Prediction System. A global meteorological model operated by the Department of Defense.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

Physical equipment used in data processing. Compare to firmware, software.

A modification of the dew cell used in radiosonde equipment.

See radiosonde commutator.