This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Thursday, June 17, 2010

Katabatic Winds and Icebergs

Image from NASA's MODIS on the Aqua satellite, taken March 11, 2010. Image is true-color.

Strong winds can occur when cold dense air descends down a glacier or ice sheet.  The winds can be hurricane speed, but more commonly are about 10 knots.  These winds are variously termed katabatic, gravity, or mountain winds.  The name originated from the Greek word katabatikos, which means "going downhill." In the Antarctic these winds then blow across the ocean water, producing ice crystals on the surface (the blue-gray areas of the photo in the area labeled "Southern Ocean).  The winds are moving from the lower left toward the upper right.  The winds then push the newly formed sea ice toward the north.  Drifting icebergs (the bright white fragments) interrupt the flow of the winds, blocking the ice formation in small areas on their leeward sides (dark areas are open water).  Related article at NASA Earth Observatory.

No comments: