That part of snow melt that reaches stream channels as runoff.

An instrument for the measurement of both solar and terrestrial radiation.

Same as ombrometer.

General name for an instrument designed to measure the vertical component of the wind speed. See anemoclinometer.

A power supply which achieves its output regulation by means of one or more active power handling devices which are alternately placed in the "off" or "on" states. It is more efficient than linear supplies which vary the conduction of power devices to ach ...

The size of the area comprising a watershed or river basin. Also called catchment area.

A buoyant balloon kept from rising freely by means of a line secured to a point on the ground, as opposed to a free balloon. See kytoon.

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

Determination of the total amount of snow covering a watershed or a given region. Both depth and water content of the snow may be measured, and the results may be used to predict the amount of water that will be available after melting.

The play or loose motion in an instrument due to the clearance existing between mechanically contacting parts.

Frequency Shift Keying. A form of frequency modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

A rainbow formed by light rays which have been reflected from an extended water surface. Not to be confused with a reflected rainbow whose image may be seen in a still body of water. The center of a reflection rainbow is at the same elevation as the sun b ...

The depth of water that would result from the melting of snow or ice, assuming measurement on a horizontal surface and no infiltration or evaporation.

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

A balloon designed to float at a constant pressure level. This may be accomplished by a pressure valve which controls the release of ballast so as to maintain flight above a selected pressure level until the supply of ballast is exhausted. See Moby Dick b ...

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

Instrument for measuring the depth of water from precipitation that is assumed to be distributed over a horizontal, impervious surface and not subject to evaporation.

A contact anemometer connected to an electrical circuit which is so arranged that the average wind speed is indicated.

Phase Shift Keying. A form of phase modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.