The depth below which the ground is saturated with water. No water table exists if the ground water is confined by an overlying impermeable stratum, as in the case of artesian ground water.

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

Either of two colored luminous spots that appear at points 22

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

Contraction for radiosonde observation.

The range of operating conditions of a device within which operating influences are negligible. The range is usually narrow. Reference operating conditions are the conditions under which reference performance is stated and the base from which the values o ...

A hydrostatic principle that pressure supplied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the containing vessel.

An instrument for the measurement of the radon content of the atmosphere.

A precipitation gauge consisting of a receiver in the shape of a funnel which empties into a bucket mounted upon a weighing mechanism. The weight of the catch is recorded as inches of precipitation.

A general term for instruments which sample atmospheric suspensoids by impaction. Same as impactometer.

The actual time during which physical events take place.

A plastic molding component formed by the reaction of phenol and formaldehyde. It can be heavily reinforced or "filled" with glass fibers or other materials. Phenolics are known for their high impact strength, excellent wear characteristics, and dimension ...

Programs or instructions which are stored in readonly memory.

Balance of the water resources of a region, comparing precipitation and inflow with outflow, evaporation, and accumulation.

The measuring, transmitting, receiving, and indicating apparatus for obtaining the value of a quantity at a distance.

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

A form of data transmission in which the bits of each character are all sent simultaneously, resulting in extremely fast communication but requiring a communication path for each bit. Compare to serial data transmission.

A sounding balloon which, when operationally inflated, resembles an inverted teardrop.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

An instrument for the measurement of the net flux of downward and upward total (solar and terrestrial) radiation through a horizontal surface.