A class of rain gauge in which the level of the collected rain water is measured by the position of a float resting on the surface of the water.

A momentary decrease in the speed of the wind.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

Temperature of equilibrium between the liquid and vapor phases of a substance at a given pressure.

A temperature scale based on absolute zero. Same as Kelvin temperature scale.

Snow gauge composed of a metal cylinder, closed at one end, used to obtain a sample of snow from which the water is measured after melting.

A device used on certain types of instruments to prevent unwanted radiation from affecting the measurement of a quantity. Also called solar radiation shield.

Same as aneroid barometer. Holostelic means wholly made of solids, while aneroid means devoid of liquid.

A method of streamflow routing which assumes that storage is a linear function of the weighted flow in the reach and is adaptable to a simple mathematical solution.

Old snow that has become granular and compacted as a result of melting and refreezing.

The lowest value of a measured quality at which a sensor responds. Compare to tracking.

A weakly colored lunar halo identical in form and optical origin to the solar parhelion.

Determined by weighing a special type of wooden stick that has been exposed in the woods, its weight being proportional to its contained water.

See radiosonde commutator.

An anemometer which measures wind speed by means of the properties of wind-borne sound waves. It operates on the principle that the propagation velocity of a sound wave in a moving medium is equal to the velocity of sound with respect to the medium plus t ...

A unit measure of electrical conduction. The facility with which a substance conducts electricity, as represented by the current density per unit electrical-potential gradient in the direction of flow. Electrical conductivity is the reciprocal of electric ...

A recording siphon barometer.

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

Very small precipitation drops (diameters less than 0.5 mm) that appear to float with air currents while falling in an irregular path. Unlike fog droplets, drizzle falls to the ground.

Radiation coming from the solid angle of the sun's disc, as opposed to diffuse sky radiation, effective terrestrial radiation, or radiation from any other source. Direct solar radiation is measured by pyrheliometers.