See calorie.

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.

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

Dihydrogen oxide, molecular formula H2O.

An instrument used to measure the amount of dew formed on a given surface.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

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

The value of the quantity measured, as indicated or otherwise provided by a measuring instrument.

Downward-facing pyranometer used for measuring reflected solar radiation.

Same as atmometer.

Rain gauge which registers precipitation that is too light to be registered by ordinary recording of the depth of water from precipitation. Same as ombrometer.

Force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.

A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation. Elements evaluated include temperature, humidity, pressure, wind speed, and wind direction.

In general, any object that reflects incident energy. Usually it is a device designed for specific reflection characteristics.

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

A sudden, significant increase in station pressure.

Apparatus in which radar techniques are used to determine the range, elevation, and azimuth of a balloonborne target, to computer upper-air wind data. It is a type of rawin system.

An instrument which automatically determines the size distribution of raindrops.

Tables prepared from the psychrometric formula and used to obtain vapor pressure, relative humidity, and dew point from values of wet-bulb and dry-bulb temperatures.