Salinity and freshwater content changes

Salinity is an essential indicator of the freshwater budget, but direct salinity observations are extremely sparse in the Arctic Ocean. In this section, we examine the freshwater content changes (referred to 34.8 PSU as in Proshutinsky et al., 2009) and compare them with TOPAZ4 results. Freshwater content and SSS variability in the Beaufort Sea are taken as an example to analyze the differences to TOPAZ4.
After the assimilation, a freshening is noticeable in the interior of the Arctic Ocean (Figure 9a). At the same time, along the routes of outflowing Arctic water into the North Atlantic east and west of Greenland, a reduction of freshwater content can be seen. Circulation changes (vectors in Figure 9a) depict an enhanced anti-cyclonic circulation anomaly in the Canadian Basin and a weaker anti-cyclonic circulation anomaly in the Eurasian Basin. We also note an increase of Atlantic inflow west of Svalbard and St. Anna Trough and enhanced Arctic outflow through the western Fram Strait and Nares Strait. The freshwater comes mostly from the direct adjustment of the initial salinity of the year 2007 (Figure 9b). It then is redistributed towards the Canadian Basin via the mean circulation. The enhanced circulation around Greenland would, according to Köhl and Serra (2014), contribute to the reduction of the freshwater content. The additional freshwater content remains stored in the Canadian Basin through the enhanced anti-cyclonic circulation, as revealed by Morison et al. (2012).