Salinity regime of the northwestern Bering Sea shelf

Abstract

The present study has examined the long-term variability of water mass properties and its relation to sea ice production (SIP) in the northwestern Bering Sea shelf using hydrographic and satellite data, and output from atmospheric reanalysis. As per our analysis of hydrographic data in the summer seasons, significant variability in bottom water temperature and salinity was noted. The temperature in 2018 showed particularly remarkable warming of the whole water column throughout the Gulf of Anadyr (GOA) and cold pool (CP) region. These oceanic parameters exhibited correlations with SIP in the Anadyr polynya, which is identified as one of the most active polynyas in the Northern Hemisphere. Specifically, there were more saline and colder water during high-SIP years, suggesting the influence of dense shelf water (DSW) that is formed during freezing processes; however, in low SIP years, bottom salinity has been observed to behave inversely, resulting in more saline water with lower SIP. We suggest that the influence of warm and saline water, originating from the Pacific, transported by ocean currents intensified by wintertime southerly winds in low-SIP years. The properties of bottom water in the semi-closed GOA are influenced by intrusion of the Pacific-originated water and DSW.