A device used to hold liquid-in-glass maximum and minimum thermometers in the proper recording position inside an instrument shelter, and to permit them to be read and reset. See Townsend support.

See mote.

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

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

An instrument for measuring differences of electric potential.

A precipitation gauge consisting of a receiver in the shape of a funnel which empties into a bucket mounted upon a weighing mechanism. The weight of the catch is recorded as inches of precipitation.

Name sometimes given to a transmissometer.

A coating of ice, generally clear and smooth. formed by the freezing of supercooled water on a surface.

The length of air flow past a wind vane required for the vane to respond to 50 percent of a step change in wind direction. Expressed in feet or meters and calculated from delay time times wind tunnel speed.

A device for obtaining a continuous record of stage at a point on a stream. The most common recorders consist of a float-actuated pen which traces a record on a clock driven chart.

A type of atmometer. It is a pan used in the measurement of the evaporation of water into the atmosphere. The NWS Class A pan is a cylindrical container 48 inches in diameter and 10 inches deep.

A wave disturbance in airflow due to some barrier in the flow. i.e. a hill or mountain.

Central Processing Unit. The part of a computer which controls and directs all functions.

A graphical aid used in the reduction of data from a winds aloft observation.

Same as luminous intensity.

In a system of moist air, the dimensionless ratio of the mass of water vapor to the total mass of the system.

A method of streamflow routing which assumes that storage is a linear function of the weighted flow in the reach and is adaptable to a simple mathematical solution.

A photometric unit of illuminance or illumination equal to one lumen per square meter

A form of psychrometer with wet-bulb and dry-bulb thermometers mounted on opposite sides of a specialty designed graph of the psychrometric tables. It is so arranged that the intersections of two curves determined by the wet-bulb and dry-bulb readings -yi ...