Improvement of Air－Sea Turbulent Fluxes Parameterization Scheme in GAMIL Model and Its Impact on Simulation of Interannual Variations of Atmospheric Circulation

The parameterization scheme (GAMIL scheme) of air－sea turbulent fluxes in the GAMIL1.0 model is improved by considering the contribution of the mesoscale convection to the sea surface fluxes. The new parameterization scheme is named GAMIL_rev scheme. The interannual variability of general circulation is simulated by the GAMIL1.0 model with the original parameterization scheme (GAMIL scheme) and GAMIL_rev scheme of air－sea turbulent fluxes, where the model is driven by the observational SST data from January 1979 to December 2000. Results show that, using GAMIL_rev scheme, the simulated tropical sea surface turbulent heat fluxes are strengthened，and the simulating capability of interannual variability of precipitation in the tropics is significantly improved, where the condensation latent heat released by precipitation is simulated more reasonably. The reasonable heating significantly improves the simulations of the interannual variability of general circulation,especially over the North Pacific in winter (DJF) and the middle-latitude South Pacific in summer (JJA). The interannual variability and spatial patterns of the Southern Oscillation (SO) and the North Pacific Oscillation in winter are represented much better by the GAMIL_rev scheme than by the GAMIL scheme. Especially, the weak intensity of SO simulated by the GAMIL1.0 model is significantly strengthened by considering the enhancement of sea surface fluxes contributed by the mesoscale convection.