A seasonal wind of persistent direction, characterized by a pronounced change in direction between seasons.

The maximum distance along the runway at which the runway lights are visible to a pilot at touchdown. Runway visual range may be determined by an observer located at the end of the runway, facing in the direction of landing, or by means of a transmissomet ...

Same as evaporative power.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

A vent used with pressure sensors to reduce the effect of wind on the pressure inlet. It is normally mounted remotely and connected to the sensor using airtight tubing.

A basic equation in daytime visual range theory, relating the apparent luminance of a distant black object, the apparent luminance of the background sky above the horizon, and the extinction coefficient of the atmosphere, or the air layer near the ground. ...

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.

A local variation of the wind vector or any of its components in a given direction.

A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature.

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

A faintly-colored circular arc similar to a rainbow but formed on fog layers containing drops whose diameters are 100 microns or less. Also called mistbow, white rainbow.

A unit of energy equal to 1.356joules.

A water-temperature thermometer provided with an insulated container around the bulb. It is lowered into the sea on a line until it has had time to reach the temperature of the surface water, then withdrawn and read. The insulated water surrounding the bu ...

A device for measuring the frequency of occurrence of atmospherics whose intensity is greater than a predetermined level.

in United States weather observing practice, the highest "instantaneous" wind speed recorded at a station during a specified period, usually the 24-hour observation day. Therefore, a peak gust need not be a true gust of wind.

The standard deviation (positive square-root of the variation) of the errors associated with physical measurements of an unknown quantity, or statistical estimates of an unknown parameter or of a random variable.

A temperature scale on which the freezing point of water equals 32

An instrument which measures the transmissivity of the atmosphere between two points for the determination of visual range.

An instrument for photographing the corona and prominences of the sun at times other than at solar eclipse.

Same as windsock.