Surface Heat Flux over Tropical Oceans in AMIP Simulations

The performance of 20 climate models participating in the second phase of the Atmospheric Model Intercomparison Project (AMIPⅡ) is evaluated concerning surface heat flux over the tropical oceans. Comparison of the AMIP surface heat flux is made with that from the Objectively Analyzed Air- Sea Fluxes (OAFlux) and in situ buoys. The annual mean values of shortwave (Q_SW), longwave (Q_LW), latent heat (Q_LH) and sensible heat (Q_SH) from model ensemble mean (OAFlux) are 217 (222), 59 (53), 121 (117) and 17 (9) W m^-2 over the tropical oceans (30°S-30°N). Most models overestimate in oceans away from the equator (especially northern and southern Pacific Oceans and southern Indian Ocean) for Q_LH and Q_SH, and in oceans near the equator for radiative fluxes. Underestimation of Q_SW is compensated by overestimation of Q_LW leading to a small difference in net radiative flux at the surface. On the other hand, Q_LH and Q_SH are both overestimated in the model leading to a larger error in turbulent heat flux (Q_LH + Q_SH). The causes behind the model error and their implications are explored.