A reversing thermometer which is encased in a strong glass outer shell that protects it against hydrostatic pressure. Compare to unprotected thermometer.

In general. the severe wind of an intense tropical cyclone (hurricane or typhoon). The term has no further technical connotation, but, unfortunately, is easily conftlsed with the strictly defined hurricane-force wind,

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

A warm, dry wind on the lee side of a mountain range, the warmth and dryness due to adiabatic compression upon descent.

Any conventional barometer fitted with an extended scale so that atmospheric pressure measurements may be made at both high and low altitudes.

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.

Lowest altitude in the atmosphere over a given location at which the air temperature is 0

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 ...

That stage, on a fixed river gauge, at which overflow of the natural banks of the stream begins to cause damage in any portion of the reach for which the gauge is used as an index.

Same as geostrophic wind level.

Apparatus from which the nature and time of precipitation may be determined.

A hygrometer in which the rotation of the hygrometric element is a function of humidity.

The mean difference between the readings of a given instrument and those of a standard instrument.

The point (physical and/or electrical) where two distinct data processing elements meet.

A self-recording psychrometer.

A thermometer based upon the principle that the velocity of a sound wave is a function of the temperature of the medium through which it passes. Sonic thermometers possess very short time-constants and eliminate radiation error.

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 ...

An effect noted primarily in wet snow conditions when snow clings to the sides of a precipitation gauge and gradually accumulates until the gauge orifice is capped with accumulated snow. This effect can be minimized by using large collectors, and wind scr ...

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.

A graphical representation of stage or discharge at a point on a stream as a function of time.