A model study of interannual and decadal variability of the arctic and sub-arctic oceans

In this work I investigate the interannual and decadal variability in the properties and the transformations of the Atlantic Water (AW) mass using an Ocean General Circulation Model. A course resolution tri-polar grid coupled ocean/sea ice model (NEMO-OPA/ NEMO-LIM) is forced with atmospheric parameters from NCEP/NCAR reanalysis. The quality of the model is assessed through comparison with observations. -- The model results show that there are in general two major processes that influenced the heat and salt balance of the Arctic and Sub-Arctic between 1985 and 2005. In the first decade of this period the volume flux of Atlantic Water into the Nordic Seas was not balanced by the outflow of Atlantic Water into the Arctic. This was a period of increase of the Atlantic Water volume and temperature in the Nordic Seas. Secondly, the Atlantic Water inflow into the Nordic Seas was warmer and saltier than normal between 1995 and 2005. These two processes caused a rise in the model temperature of the Arctic and Sub-Arctic similar to observed warming trend in these regions