The Southeastern Tropical Atlantic SST bias investigated with a coupled atmosphere-ocean single column model at a PIRATA mooring site
Published in Journal of Climate, 2020
Recommended citation: Deppenmeier, A., R.J. Haarsma, C. van Heerwaarden, and W. Hazeleger, 0: The Southeastern Tropical Atlantic SST bias investigated with a coupled atmosphere-ocean single column model at a PIRATA mooring site. J. Climate, 0, https://doi.org/10.1175/JCLI-D-19-0608.1 https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-19-0608.1
In this paper we investigate the long-standing southeastern tropical Atlantic warm sea surface temperature (SST) bias with a novel coupled atmosphere-ocean single column model (SCM). We focus on boreal summer, in which the tropical Atlantic cold tongue develops rapidly. The observed cooling cannot be matched in coupled global climate models, which leads to a warm bias. The SCM produces a very similar bias 5 days into the simulation. We find that by nudging the atmosphere to reanalysis we reduce the bias by 40%. This is is a sizeable reduction, but we can do even better than that. By increasing the efficiency with which available turbulent kinetic energy in the ocean leads to ocean vertical mixing we reduce the warm SST bias by 70%. This result is robust whether we leave the atmosphere to evolve freely or nudge to reanalysis.
Recommended citation: Deppenmeier, A., R.J. Haarsma, C. van Heerwaarden, and W. Hazeleger, 0: The Southeastern Tropical Atlantic SST bias investigated with a coupled atmosphere-ocean single column model at a PIRATA mooring site. J. Climate, 0, https://doi.org/10.1175/JCLI-D-19-0608.1