Surface latent heat flux and its relationship with sea surface temperature in the National Centers for Environmental Prediction Climate Forecast System simulations and retrospective forecasts

The present study evaluates surface latent heat flux (LHF) and its relationship with sea surface temperature (SST) in the NCEP Climate Forecast System (CFS) simulations and retrospective forecasts. Mean LHF in the CFS is higher than satellite estimates in the Tropics due to a dry bias in surface air humidity. The SST forced Global Forecast System simulation produces larger interannual variability of LHF compared to the CFS coupled simulation. The LHF-SST correlation in the CFS simulation and retrospective forecasts shows large differences from observations in the eastern equatorial Indian Ocean and western-central equatorial Pacific due to an excessive SST dependence in the sea-air humidity difference in relation to a low bias in surface air humidity. In the eastern equatorial Indian Ocean, the CFS simulation disagrees with observations regarding the role of LHF in the development of SST anomalies during boreal summer.