A hygrometer based upon the diffusion of water vapor through a porous membrane.

The record of a barograph.

A thermometer using transducing elements which deform with temperature. Examples are the bimetallic thermometer and the Bourdon tube type of thennometer.

See hook gauge.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

Quantitative Precipitation Forecast.

film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...

A component of a radiosonde consisting of a series of alternate electrically conducting and insulating strips. As these are scanned by a contact the radiosonde transmits temperature and humidity signals alternately. The contact may be a baroswitch as in t ...

In folklore, a name for rain.

A clockwise change in wind direction. Veering winds with height are indicative of warm air advection (WAA).

A special form of the aspiration psychrometer. developed by Assmann, in which the thermometric elements are well shielded from radiation. Psychrometric measurements may be taken with the instrument in the presence of direct solar radiation.

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

Companion to the wet-bulb thermometer in a psychrometer. Used to measure ambient air temperature.

A computed characteristic of a particular river basin, expressed as the time difference between the time-center of mass of rainfall and the time-center of mass of resulting runoff.

The temperature at which all three phases of a substance can exist in equilibrium. This temperature occurs at only one pressure. The triple-point of water is 273.16 K and is the basis of the Kelvin scale.

An optical instrument which consists of a sighting telescope mounted so that it is free to rotate around horizontal and vertical axes, with graduated scales so that the angles of rotation may be measured. Used to observe the motion of a pilot balloon.

Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

The addition of one or more redundant bits to information to verify its accuracy.

An increase in the central pressure of a pressure system; opposite of a deepening. More commonly applied to a low rather than a high.

An instrument for measuring snow hardness in terms of the resistance of snow to the pressure exerted by a disk attached to a spring-loaded rod, a gauge calibrated in pounds per square inch registers the amount of resistance. See Canadian hardness gauge.