Arctic Freshwater and Global Change

Contact: Dr. Dorothea Bauch

Important factors of the Arctic environment are the inflow of warm and saline waters from the Atlantic Ocean and the cold and low salinity halocline. The fresh surface layer of Arctic river runoff (10% of global total runoff) and its associated cold halocline layer (see Fig. 1) normally act to isolate the sea-ice cover from the warm and saline Atlantic-derived layer below. Within the ongoing discussion on Arctic and global climate change it has now been recognized that the performance of the cold halocline in insulating the Arctic sea-ice cover cannot be taken for granted. Whether the Arctic halocline, which is largely determined by the distribution and supply of fresh and brine waters from the shelf regions to the interior basin, is a permanent and stable feature, remains an urgent and largely open question. Without an answer to this question it is not possible to find satisfactory projections on Arctic and global climate change. We are contributing to the answer by (1) investigating the exchange of freshwater and brine water along the Eurasian continental margin and estimating reasonable shelf-basin exchange rates (Eurasian Margin Freshwater Exchange (pdf)) and byinvestigating freshwater contributions in the central Arctic Ocean within the Transpolar Drift and the influence of Pacific-derived waters (Impact of Arctic Freshwater (pdf)). (2) Additionally we are investigating the changes in sea-ice processes on the Arctic shelves in respect to the Arctic halocline (see subproject 3A of joint Russian-German research project “Transdrift” Based on hydrological data and stable oxygen isotope analysis (δ18O) we can quantify the influence of shelf-derived freshwaters and brine-enriched (Background Information on Methods (pdf)).

Related projects:

Verbundprojekt: Transdrift