An instrument used for measuring the specific gravity of a liquid.

A hygrometer which determines the amount of precipitable moisture in a given region of the atmosphere by measuring attenuation of radiant energy caused by the absorption bands of water vapor.

Generic term for rapid variations in apparent position, brightness, or color of a distant luminous. object viewed through the atmosphere.

A transducer for converting thermal energy directly into electrical energy. It is composed of pairs of thermocouples which are connected either in series or in parallel. Thermopiles are used in thermoelectric radiation instruments when the output of a sin ...

A water-temperature thermometer provided with an insulated container around the bulb. It is lowered into the sea on a line until it has had time to reach the temperature of the surface water, then withdrawn and read. The insulated water surrounding the bu ...

A pyrheliometer of the thermoelectric type. Radiation is allowed to fall on two concentric silver rings, the outer covered with magnesium oxide and the inner covered with lamp black. A system of thermocouples (thermopile) is used to measure the temperatur ...

Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.

An instrument for determining the direction of cloud motion. There are two basic designs of nephoscope, the directvision nephoscope and the mirror nephoscope.

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.

Old snow that has become granular and compacted as a result of melting and refreezing.

Formation of a single water drop by the union of two or more colliding drops.

See approximate absolute temperature scale, Celsius temperature scale, centigrade temperature scale, Fahrenheit temperature scale, Kelvin temperature scale, Rankine temperature scale, Reaumur temperature scale,

A recording siphon barometer.

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

A captive balloon used to maintain meteorological equipment aloft at approximately a constant height. The kytoon is streamlined and combines the aerodynamic properties of a balloon and a kite.

An instrument for measuring the frost point of the atmosphere.

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

A scale of yellows, greens, and blues for recording the color of sea water, as seen against the white background of a Secchi disk.

Same as Aeolian.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.