A device for measuring the river stage. Also called stream gauge.

An addition to a rawinsonde system which allows determination of the slant range to the radiosonde.

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.

A thermopile used in some types of radiation instruments. See solarimeter.

A rotation anemometer which has a horizontal axis upon which helicoidal shaped vanes are mounted. See windmill anemometer.

A synoptic code approved by the World Meteorological Organization in which the observable meteorological elements are encoded and transmitted in "words" of five numerical digits length. Often abbreviated synoptic code.

A forecast of the expected stage or discharge at a specified time, or of the total volume of flow within a specified Interval of time, at one or more points along a stream.

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 type of electrical thermometer in which the thermal element is a substance whose electrical resistance varies with the temperature. Such thermometers can be made with very short time constants and are capable of highly accurate measurements.

A magnetometer of the electromagnetic type which is used to measure the horizontal intensity of the earth's magnetic field.

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.

A photometer which measures the intensity of radiation as a function of the frequency (or wavelength) of the radiation.

Winds which, over a small area, differ from those which would be appropriate to the general pressure distribution.

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

A line of equal or constant temperature.

The total amount of water transferred to the atmosphere by evapotranspiration.

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

See photometer.

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

A type of modulation in which the frequency of a continuous radio carrier wave is varied in accordance with the properties of a second (modulating) wave.