Mid-depth Subtropical Water Circulation and Distribution Near Tidewater Glaciers in Uummannaq Fjord, West Greenland

Abstract:

The melting of grounded glaciers and ice sheets contribute about 65% of total global mean sea level rise and are responsible for about 50% of its acceleration from 2 to 3 mm yr^-1 over the past two decades. Remote sensing and in situ observations have revealed that much of Greenland Ice Sheet mass loss has been synchronous with a temperature increase of the relatively warm subsurface waters of the subpolar North Atlantic Ocean that circulate around the island’s continental shelf. At key locations, these warm waters cross the continental shelf and are able to reach fjords with outlet tidewater glaciers terminating in direct contact with the ocean. The existence of these warm waters in fjords with shrinking outlet glaciers has been previously documented at several locations around Greenland. Here we use oceanographic data collected in August 2012 and 2013 to show for the first time the existence and distribution of these warm waters throughout Uummannaq Fjord, a major fjord complex in West Greenland. The distribution of these warm waters in conjunction with estimates of ocean circulation and new ocean seafloor measurements reveals the set of glaciers that are likely venerable to enhanced submarine melting in a warming climate.