River Water and Brine Inventory over the Laptev Sea Shelf: 2007 To 2011

Abstract:

Five years of oxygen isotope and hydrological survey reveal interannual variations in the inventory and distribution of river water over the Laptev Sea. Our results suggest that the Arctic Dipole Anomaly might connect the Laptev Sea river water inventory and the global Arctic freshwater inventory.

In 2007, 2009 and 2010 relatively low amount of river water (≤1500 km³) was found and was mostly located in the southeastern Laptev Sea. In 2008 and 2011, high amounts of river water (~1600 km³ and ~2000 km³) were found, especially in the central and northern part of the shelf, suggesting a northward export of this water. It has been suggested that atmospheric forcing mainly controls the Laptev Sea summer surface hydrography and for this period, the interannual variability or summer river water inventory is coherent with the summer Arctic Dipole index. This could suggest that the Arctic Dipole has been a dominant forcing controlling the distribution and the fate of river water discharged within the Laptev Sea over the 2007-2011 period, which is concurrent with the recently highlighted persistent shift in early summer Arctic atmospheric circulation (Overland et al., 2012, GRL 39, L19804). The variation in river water inventory over the Laptev Sea Shelf is also positively related with recent Arctic Basin and Beaufort Gyre freshwater inventory (with a 2-yrs lag), which suggest that the river water originating from the Laptev Sea have an impact on the global Arctic freshwater inventory.

During the same period the brine inventory was also variable but was dissociated from the river water inventory variation suggesting that, during this period different forcing was influencing the brine inventory.