katabatic

(thing) by Richard (5.3 y) Wed May 31 2000 at 16:44:40
A meteorological term applied to winds which blow downhill due to cold air being pulled by gravity from high ground to low ground. Examples of katabatic winds are found in Greenland and Antarctica.

Etymologically derived from the German katabeinen meaning to descend.

(thing) by maxClimb (1.1 hr) Wed Feb 07 2001 at 15:29:30
Katabatic flow is a common, daily occurrence worldwide. Solar heating tends to cause upslope flow in valleys during the warm part of the day, unless there is some overriding larger scale weather situation. When the sun gets low at the end of the day and stops heating the valley much of the air that was pushed up and out flows back down the hillsides into the valley. If the valley is well defined and not too wide then the air flowing down the various slopes will converge over the center of the valley, and there will be a broad area of smoothly rising air there. This is known as a Wonder Wind and is highly valued by pilots of soaring aircraft.

There are seasonal winds that flow over and down mountains and so are sometimes described as katabatic, but they are, like the Santa Ana winds of Southern California, the result of large scale conditions (strong high pressure over Utah and the Great Basin in the case of Santa Ana winds) and not diurnal heating/cooling cycles. See foehn.
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