A transducer for converting thermal energy directly into electrical energy. It is composed of pairs of thermocouples which are connected either in series or in parallel. Thermopiles are used in thermoelectric radiation instruments when the output of a sin ...

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

The time required for an instrument to register a designated percentage (frequently 90%) of a step change in the variable being measured.

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

A rainbow seen in the spray of the ocean. It is optically the same phenomenon as the ordinary rainbow.

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

The record of a barograph.

A conically shaped, copper rain gauge shield.

An evaluation, according to set procedures, of those weather elements which are most important for aircraft operations. Always includes cloud height or vertical visibility, sky cover, visibility, obstructions to vision, certain atmospheric phenomena, and ...

force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

Force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

An anemometer utilizing the principle that the pitch of the aeolian tones generated by air moving past an obstacle is a function of the speed of the air. Largely a curiosity and has been put to no practical application in modem meteorology.

A faintly-colored circular arc similar to a rainbow but formed on fog layers containing drops whose diameters are 100 microns or less. Also called mistbow, white rainbow.

An instrument for measuring differences in electric potential.

A protocol similar to RS232 which makes use of differential transmission to provide high speed data transmission over significantly longer distances.

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

pattern barometer-Mercurial barometer with a fixed scale and cistern and which therefore requires only one adjustment before each reading.

A general term for instruments designed to measure the amount of cloudiness.

The physical exposure of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and not always correctable. The purpose of the instrument shelter is to prov ...

A measure of luminous flux remaining in a light beam after it has passed through a specified distance of the atmosphere.