Katabatic wind

Formation and effect (polynya formation) of the katabatic winds in the Antarctic

Catabatic wind over an ice shelf

The katabatic wind (Greek: katabatikos - flowing down) is a cold offshore fall wind . The katabatic winds include:

• The bora on the Adriatic coast ,
• the Mistral in the Rhone Valley,
• the Reshabar in the south of the Caucasus ,
• the Williwaw with the Aleutians ,
• the Elvegust of the Norwegian fjords ,
• the Piteraq in Greenland ,
• the Joran at the southern foot of the Swiss Jura and
• the Böhmwind in Germany and Austria.

Glacier winds also belong to the katabatic winds.

A catabatic wind usually arises as a result of a stable atmosphere stratification (potential air temperature increases with altitude) under the influence of gravity (vertically downwards directed force) and pressure equalization with warmer air (horizontally outwards directed force).

Air cools down over the ice surface of a high plateau, a mountain or a glacier , so that its density increases. The cold, catabatic fall wind is created as a pressure equalizing flow with the warmer environment. Katabatic winds play an essential role in the formation of Antarctic sea ​​ice and thus in the formation of Antarctic bottom water as well as in the formation of coastal polynjas (openings in the sea ice). The phenomenon is particularly pronounced in front of the extensive ice shelf fields in the Ross Sea and the Weddell Sea .

The downwinds of the Antarctic are the strongest winds in the world and can reach speeds of up to 300 km / h.

The foehn does not belong to the katabatic winds, since the foehn is a warm wind. Its drive does not come directly from gravity.

Web links

Commons : Katabatic Wind  - collection of images, videos and audio files

• Günther Heinemann, Thomas Ernsdorf, Clemens Drüe (2011): Investigation of Katabatic winds and Polynyas during Summer - IKAPOS: Field phase report. Reports on Polar and Marine Research, 633.
• Weather AZ - Katabatic Winds By Bill Giles OBE, BBC Weather Center ( April 9, 2009 memento on Internet Archive )

Individual evidence

1. ^ Winds of the world on weatheronline.co.uk
2. ↑ Ferenc Baki: Diploma thesis: The Joran - A fall wind at the southern foot of the Jura. (PDF; 6.7 MB) (No longer available online.) 2007, archived from the original on July 15, 2017 ; accessed on January 1, 2018 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
3. ↑ The Antarctic on the website of the Federal Environment Agency , accessed on February 6, 2016