A rain gauge which automatically records the amount of precipitation collected, as a function of time.

The component of the radiosonde which includes the modulating blocking oscillator and the radiofrequency carrier oscillator.

The programs and instructions which direct a computer.

A wind (or component thereof) directed down the slope of an incline and caused by greater air density near the slope than at the same levels some distance horizontally from the slope. Also called drainage wind and sometimes called katabatic wind.

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.

A unit of luminance or brightness equal to 1/d candles per foot'.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

Any device or instrument for measuring salinity, especially one based on electrical conductivity methods.

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

The process by which small particles suspended in a medium of a different refractive index diffuse a portion of the incident radiation in all directions. In scattering no energy transformation results, only a change in the spatial distribution of the radi ...

A type of rain gauge shield consisting of freely hanging, evenly spaced slats arranged circularly around the gauge. The advantage of this shield is that the slats do not easily accumulate snow, permitting its use on unattended gauges. See rain gauge shiel ...

A reversing thermometer which is encased in a strong glass outer shell that protects it against hydrostatic pressure. Compare to unprotected thermometer.

Wind with a speed between 11 and 16 knots (13 and 18 mph); Beaufort scale number 4.

A line of equal or constant pressure.

Graduated fixed stake used in regions of abundant snowfall to facilitate the measurement of snow depth.

A temperature scale on which the freezing point of water equals 32

A temperature telemeter.

An instrument used to determine atmospheric pressure or elevation by observing the boiling point of water or both liquids. The sensitivity of the hypsometer increases with decreasing pressure, making it more useful for high altitude work.

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