Atmospheric variability related to ocean features – dependence on time and space scale

Recent work suggests that there is forcing of the atmosphere by the ocean in mid-latitudes on timeperiods of monthly to interannual. Here we examine how the co-variability of ocean and atmosphere changes as a function of time scale and spatial scale. In particular we aim to distinguish between the ocean mesoscale and larger, basin scales, as well as the synoptic atmosphere timescale vs the longer periods on which the ocean varies. We use observational estimates and long (~100 year) simulations of the Community Earth System Model, with and without an eddy-resolving ocean model. A key finding is that for spatial scales related to the ocean mesoscale, and for time periods of monthly to interannual, forcing of atmosphere by ocean leads to significantly enhanced variability of surface turbulent heat fluxes and convective precipitation. Finally we discuss the implications of the coupling for ocean variability and jets.