Ocean eddy-driven climate variability

Current IPCC class coupled climate models do not resolve mesoscale ocean features that are essential for capturing realistic ocean heat transport, coupled ocean-atmosphere interactions and their consequent impacts on regional climate. We use the Community Climate Systems Model (CCSM4) with a one-tenth degree ocean component and find seasonal-to-decadal climate phenomenon that are otherwise not represented in current IPCC-class models. For instance, on seasonal-to-intra-annual timescales, we find that a retreated Loop Current within the Gulf of Mexico is related to reduced precipitation over southern continental US but enhanced precipitation over the Intra-Americas Seas (IAS) and Caribbean islands. This may be due to better resolved Caribbean Current bringing warm tropical waters into the IAS and supporting convective precipitation. On interannual timescales, we identify a tropical-subtropical oceanic teleconnection between SST over the Agulhas leakage and wind stress curl over tropical Indian Ocean associated with ENSO. This suggests the use of ENSO as a predictor for Agulhas leakage interannual variability. On decadal timescales, we find the atmospheric jet responding to shifts in western boundary currents over the North Atlantic, with implications on precipitation over continental US and Europe.