Behavior of water masses around the Chukchi Borderland, western Arctic Ocean

Abstract

We investigated the behavior of water masses around the Chukchi Borderland (CB) in the western Arctic Ocean using historical hydrographic survey data and yearlong ocean mooring data. The water masses were mainly analyzed with salinity, temperature, and ocean current. Anomaly of sea ice extent (SIE) is negatively correlated with temperature anomaly of the Pacific summer water (PSW) whereas it is positively correlated with salinity anomaly of surface melt water (MW). It implies that oceanic heat content from the Pacific plays a significant role on melting sea ice and increasing freshwater content in the western Arctic Ocean. Yearlong temperature and water velocity data showed spatial and temporal variations of water masses over the Chukchi Plateau (CP). The westward current was dominant in the southern CP while the southward current was significant in the northern CP from summer 2014 to summer 2015. From autumn to mid-winter of 2014, PSW in the southern CP appears to be suppressed by a mixed layer beneath sea ice and sustained for nearly 4 months, indicating that substantial heat storage within the PSW layer is associated with wind pattern (northeasterly) and sea ice covering. In addition, we will discuss on the relationship between water mass and biochemical properties (e.g., dissolved oxygen, nutrients, and chlorophyll-a) to understand the ecosystem response to the variation of water masses.