Weakening and warming of the European Slope Current since the late 1990s attributed to basin-scale density changes

Abstract. Oceanic influences on shelf seas are mediated by flow along and across continental slopes, with consequences for regional hydrography ecosystems. Here we present evidence the variable North Atlantic influence European over last 4 decades using ocean analysis reanalysis products, as well an eddy-resolving model hindcast. To first order, flows oriented isobaths at slope related to poleward increase in density adjacent deep that supports a geostrophic inflow towards slope. In Atlantic, this gradient associated have undergone substantial, sometimes abrupt, changes recent decades. Inflow range 10–15 Sv is identified eastward transport temperature classes 30∘ W latitude 45–60∘ N. Associated major subpolar warming around 1997, cool fresh branch of was substantially reduced, while warm more saline strengthened, respective order 5 Sv. Total fell from ∼ 15 pre-1997 10 post-1997. hindcast, particle tracking used trace origins west Ireland Scotland before after 1997. Backtracking particles up years, subtropical pathways statistical perspective. broad terms, cold, waters provenance were replaced warm, provenance. These implications downstream regions strongly influenced inflow, particular northern Sea, where “subtropicalization” ecosystems has already been observed since late 1990s.