The total area drained by a river and its tributaries. Same as river basin.

The maximum deviation of any points from a straight line drawn as a "best fit" through the calibration points of an instrument with a linear response curve. Usually expressed as a percentage of full- scale range.

A colloquial term in western Australia for a squall, associated with thunder, on the northwest coast in summer.

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

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

A graphical aid used in fire weather forecasting to calculate the degree of forest-fire danger (or burning index). Commonly in the form of a circular slide rule, the firedanger meter relates numerical indices of (a) the seasonal stage of foliage, (b) the ...

Balance of the water resources of a region, comparing precipitation and inflow with outflow, evaporation, and accumulation.

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

Upwarddirected solar radiation, reflected by the earth's surface and the atmosphere.

A numbering system using a base number of 16 and including the ten decimal digits (0 to 9) along with six alpha digits (A to F). Thus. a digit is available to represent each of the possible values of a 4-bit binary digit.

Same as an upper air observation, but commonly used to refer to a single complete radiosonde observation.

A standard interface between a computer input/output port and a peripheral device. Signal properties including time duration, voltage. and current, are specified by the Electronic Industries Association.

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

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

Hygrometer in which the dew (frost) point is determined by observing the temperature of an artificially cooled surface at the moment at which dew (frost) first appears on it.

Any emission of light at temperatures below that required for incandescence.

The play or loose motion in an instrument due to the clearance existing between mechanically contacting parts.

A psychrometer in which the ventilation is provided by a suction fan.

The total infrared radiation emitted from the earth's surface. To be carefully distinguished from atmospheric radiation, effective terrestrial radiation, and insolation.

A recording weight barometer.