A counterclockwise change in wind direction. Backing winds with height are indicative of cold air advection (CAA).

An instrument which determines the altitude of an object with respect to a fixed level. There are two general types of altimeters: (a) the pressure altimeter, which gives an approximate measure of altitude from a pressure measurement and an assumed standa ...

A constant which describes the performance of a wind vane in response to a step change in wind direction. It is calculated from the relative amount of overshoot on two successive swings (half cycles) of a decaying oscillation. This specification is dimens ...

A rain gauge which indicates but does not record the amount of precipitation captured.

A recording anemoclinometer.

A system of estimating and reporting wind speed, originally based on the effect of various wind speeds on the amount of canvas that a full-rigged nineteenth century frigate could carry.

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 ...

Abbreviation for binary digit. The smallest unit of information, equal to one binary decision, i.e. 1/0, on/off, yes/no.

Closed, curved, flexible tube of elliptic cross section which is deformed, according to type, by variations of atmosphere spheric pressure or temperature and so provides a measurement of the particular parameter.

Area of a computer or other device where various logic and control elements are interconnected. Often a printed circuit board into which other circuit boards plug at right angles.

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.

A computed characteristic of a particular river basin, expressed as the time difference between the time-center of mass of rainfall and the time-center of mass of resulting runoff.

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 which indicates the presence of dust particles in the atmosphere. Also spelled coniscope.

See river basin.

The difference between amounts of precipitation and runoff for a given storm. It is that portion of the precipitation that remains in the basin as soil moisture, surface storage, ground water, etc.

The stage, on a fixed river gauge, corresponding to the top of the lowest banks within the reach for which the gauge is used as an index. Compare to flood stage.

An instrument for rapidly obtaining samples of airborne dust; a type of dust counter. Particles pass through a cylindrical chamber, are drawn at high velocity through a narrow slit, and then impinge upon a microscope cover glass located a short distance f ...

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.

film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...