Assessing changes in ocean heat transport in a shifting Arctic Climate


Arctic Research Initiative
2007 Funded Project


The Arctic is in transition towards a warmer state.The magnitude and variability of the upward heat transport in the Arctic Ocean to the surface layer, and in turn to the overlying sea ice cover, are significant variables in the Arctic climate system. The major goal of this proposal is to quantify the oceanic transport of heat from the warmer deeper Atlantic-derived waters to the upper layers. We intend to accomplish this by investigating the temperature and salinity structure and variability of the Atlantic layer and overlying water column, based on measurements from an innovative Arctic Observing System. An observing array of Ice-Tethered Profilers, deployed between 2004 and 2007, has provided detailed temperature and salinity measurements of a remarkable layering (“staircase”) structure in the water of the central Canada Basin of the Arctic Ocean. This structure indicates a vertical transport of heat from the underlying warmer water to the surface water and the ice. The structure has changed significantly since 1985 when it was last analyzed by Padman and Dillon (1987, 1988, 1989). The innovative Ice-Tethered Profiler measurements provide an unprecedented view of the spatial and temporal characteristics of the present-day staircase; our preliminary analysis reveals that today’s staircase is on average about 100 m shallower, and supports greater vertical heat transport relative to 1985.These significant differences are likely due to the recent warming of the Atlantic water that enters the Arctic Ocean. The higher heat transport has implications for the already reduced Arctic ice cover, and potential impacts on processes occurring at lower latitudes. Here we propose to use Ice-Tethered Profiler measurements to calculate the vertical heat transport through the staircase over the expansive area covered by the ITP array, and to quantify changes on decadal scale - an essential step in detecting and assessing climate change in the Arctic.