Factors controlling water mass variations over the Chukchi Borderland, Arctic

Abstract

We have carried out hydrographic surveys since 2010 to monitor the Pacific-orign waters over the Chukchi Borderland (CBL) in the western Arctic Ocean. Based on CTD data analysis, the heat content from the Pacific Summer Water (PSW) is highly correlated with sea ice extent reduction over the region. Yearlong mooring and numerical simulation data are analyzed to verify what factors lead the PSW variation. We found two factors controlling the variation of PSW over the region: variation of summer waters incoming through the Bering Strait (BS) and variation of local winds over the East Siberian Sea (ESS) shelf. Temporal variation of PSW temperature over CBL is in-phase with that of the Alaskan Coastal Water (ACW) temperature even if there is a time lag. Relatively cold water over the ESS shelf is transported to the CBL by local winds and subducted into the PSW layer by the thermohaline intrusion.