For those who live in the Northern Hemisphere, December is a time when days get steadily shorter and colder as winter settles in. In the south, however, December is the start of summer. Long sunlit days heat the frigid waters around Antarctica, releasing them from the coating of ice that developed during the winter. By mid-December, the seasonal ice in the Ross Sea had broken up and was quickly flowing away from the continent. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured the movement in this pair of photo-like images of sea ice in the Ross Sea, taken on December 12 and December 13, 2007, within the span of nine hours. The ice was shifting, bunching and drifting northward so quickly that even in the short space of time that elapsed between the two images, noticeable differences developed.
The top image shows the Ross Sea as observed by the MODIS instrument flying on the Aqua satellite at 05:10 UTC on December 13. The MODIS instrument aboard the Terra satellite captured the lower image less than nine hours earlier, at 20:25 UTC on December 12. The images show that the ice was rapidly breaking up and drifting away from Antarctica. The bulk of the ice was rotating counterclockwise, moving generally northward. This movement is particularly evident in the upper right corner of the images. Chunks of ice that had been pointing to the upper right on December 12 (lower image) are nearly vertical a few hours later (top). Some of the ice visible in the lower image had drifted north beyond the top edge of the image, and pieces of ice along the edge of the pack moved several kilometers within the image. Ice that had been clustered south of Mount Erebus in the Terra image had drifted away by the time Aqua captured the top image...
