Thursday, June 17, 2010
Katabatic Winds and Icebergs
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.