The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027)

Abstract
Pacific Water is the predominant source of freshwater, heat, and nutrients to the Arctic Ocean. The westward-flowing Chukchi Slope Current (CSC) is a major pathway transporting Pacific Water into the Arctic Ocean. However, due to the scarcity of long-term observations, the downstream pathway variability of the CSC and mechanisms remain unclear. In this study, we used a multi-satellite altimetry-derived dataset of Dynamic Ocean Topography (DOT) and geostrophic surface currents covering the period 2002–2024 to investigate the downstream pathways and variabilities of the CSC. The results demonstrate that: the downstream pathways of the CSC can be classified into three representative modes: 1) northward deflections near the Northwind Ridge, 2) the central Chukchi Plateau; 3) the northern East Siberian Sea; 4) multi-branch pathway. The downstream pathways exhibit pronounced interannual variability, with mainly mode 2 before 2009, and the mode 3 dominating during 2009–2016, then mode 1 taking over after 2016. The EOF analysis suggests the interannual variability of CSC downstream pathways is significantly associated with the extent of the BG, while the multi-branch pathway mode is more likely associated with local mesoscale eddy activities. This study provides new insights into the pathway and fate of Pacific Water in the interior western Arctic Ocean.