Changes in the properties of deep and intermediate water masses in the Nordic Seas from 1997 to 2016

Abstract. This study investigated the temporal variability of the basic physical properties of deep and intermediate waters in the Nordic Seas from 1997 to 2016. Special attention paid to quantifying changes in their temperature and salinity and determining potential drivers of these changes. Hydrographic data were obtained during annual cruises of the R/V Oceania in the Nordic Seas region from 1997 to 2016.

The results show that, in the past 20 years, deep and intermediate waters in the studied region have warmed at least 10 times more than the mean global ocean temperature change; salinity has also changed. This means that changes in these waters' properties have a much greater impact on recent climate change intensification than previously thought. For example, ocean circulation, dissolved oxygen, carbon dioxide content, and sea level rise, may also change much faster.