A recording pressure-tube anemometer in which the wind scale of the float manometer has been made linear by the use of springs, i.e. Dines anemometer.

A unit of power equal to one joule per second or 10' ergs per second.

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.

The change in barometric pressure within a specified period of time (typically 3 hours for meteorological observations).

The lowest temperature that can be obtained on a wet-bulb thermometer in any given sample of air. Obtained by evaporation of water (or ice) from the muslin wick. Used in computing dew point and relative humidity.

General name for a type of instrument which measures the inclination of the wind to the horizontal plane. See bivane.

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

Same as instrument shelter.

A device that combines several separate communications signals into one and outputs them on a single line.

Winds from the four cardinal points of the compass; that is, north, east, south, and west winds.

A weakly colored lunar halo identical in form and optical origin to the solar parhelion.

A navigational aid used to facilitate the landing of an aircraft at an airport in instrument weather, i.e. low visibility.

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

A device used by oceanographers to obtain subsurface samples of sea water. The "bottle" is lowered by wire, its valves open at both ends. It is then closed in situ by allowing a weight (called a messenger) to slide down the wire and strike the reversing m ...

Temperature of equilibrium between the liquid and vapor phases of a substance at a given pressure.

A sunshine recorder of the type in which the time scale is supplied by the motion of the sun. It consists of two opaque metal semi-cylinders mounted with their curved surfaces facing each other. Each of the semi-cylinders has a short narrow slit in its fl ...

See foehn.

Not a linear function of the relevant variables.

An absolute instrument developed by K. Angstrom for the measurement of direct solar radiation. The radiation receiver station consists of two identical manganin strips whose temperatures are measured by attached thermocouples. One of the strips is shaded, ...

A device for measuring the height of tide. It may be simply a graduated staff in a sheltered location where visual observations can be made, or it may consist of an elaborate recording instrument (sometimes called a marigraph) making a continuous graphic ...