Subglacial meltwater leaves the Antarctic ice sheet through distinct channels, suggests an article published online this week in Nature Geoscience. Such a channelized drainage system is expected to affect melt rates underneath the floating ice shelf, shelf stability and the dynamics of ice streams.
Anne Le Brocq and colleagues identified linear features on the surface of the Filchner-Ronne Ice Shelf in West Antarctica, using satellite and airborne measurements, and linked these features to channels beneath the ice shelf that are detected by radar observations. They conclude that the channels are formed from meltwater plumes that flow underneath the grounded ice sheet, and that enter the ocean at focused exit points. Because surface features such as those on the Filchner-Ronne Ice Shelf are apparent on the surface of several other ice shelves around the continent, the researchers suggest that a channelized subglacial drainage system is widespread in Antarctica.