Snapshot Of The Ocean Melting An Antarctic Ice Shelf
Contributed by Kenneth D. Mankoff | Tuesday, Mar 20, 2012

Warm water can melt ice. This simple fact can have enormous consequences: as the earth's oceans warm in a changing climate, the melting of glacial ice is accelerated, increasing the global sea level. Because sea level rise has a major impact on civilization, many scientists are now working to better understand the interactions between ice and ocean. This image shows the ocean circulation just offshore from an ice shelf in an Antarctic bay called Pine Island Bay. Although ice shelves such as this one are floating by definition, and therefore have already contributed to sea level rise by displacing water, they are thought to act as buffers or 'plugs' that slow the flow of glaciers from the land to the sea. The ice shelf is the top central part of the black-and-white portion of the image, where the vertical stripes are visible. The ocean is the colored portion of this image, with the warmest waters (red) at about zero degrees Celsius, and the coldest waters (blue) approaching the freezing point at almost minus two degrees. (The freezing point is below zero because the ocean is salty.) Perhaps surprisingly, the warmest waters appear to be flowing *outwards* from underneath the ice shelf along the right-hand side of the image. These warm temperatures hint at a complicated three-dimensional flow, where deep warm (and salty) waters are drawn underneath the ice cavity near the ocean bottom, where they melt ice and become less dense. The waters then rise and are eventually expelled at the surface of the bay, with some of their heat still intact. The author's recent work has used images such as this one to try to better understand the ice/ocean interactions in Pine Island Bay and underneath the Pine Island Glacier ice shelf, which appears to be changing rapidly in response to a warming ocean.

Caption by Open-Ocean Staff and Kenneth D. Mankoff
This material is based upon work supported by the National Aeronautics and Space Administration This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. NNX10AN83H | Disclaimer Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration | Hide
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