Same as altimeter setting.

The length of fluid flow (gas or liquid) past a sensor required for the sensor to respond to 63.2% of a step change in speed. Expressed in feet or meters. For anemometers, this value is calculated from time constant times wind tunnel speed.

An empirical curve relating stream discharge or stage at a point on a stream to discharge or stage at one or more upstream points and, possibly. to other parameters. Also called stage relation.

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

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

An aviation weather forecast for a specific flight.

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

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

The officially designated elevation of an airport above mean sea level, taken as the highest point on any of the runways of the airport. Same as airport elevation.

A protocol similar to RS232 which makes use of differential transmission to provide high speed data transmission over significantly longer distances.

A measure of the intrinsic luminous intensity emitted by a source in a given direction. Luminance is a measure only of light. The comparable term for electromagnetic radiation in general is radiance.

A high-altitude sounding system consisting of a small solid- propellant research rocket carried aloft by a large plastic balloon. The rocket is fired near the maximum altitude of the balloon flight.

See calorie.

A line drawn through all points on a map having the same amount of cloudiness.

The water volume within a specified portion of a stream channel.

The programs and instructions which direct a computer.

Pertaining to rain, or more broadly, to precipitation.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

Same as rain-intensity gauge.

The height of the cloud base above the local terrain.