Evaluation And Seasonal Variability Study Of Latent And Sensible Heat Flux In South China Sea

The sea surface turbulent heat fluxes, as the key subjects of air-sea interaction, are very important for understanding the coupled atmosphere-ocean models and oceanic heat and freshwater budget. The accuracies of latent heat flux (LHF) and sensible heat flux (SHF) in South China Sea (SCS) are needed to check firstly because of the poor quality of datasets. Using ship-based SOC (Southampton Oceanography Center) fluxes as reference, the mean fields of turbulent heat fluxes (1988-1993) from six datasets (SOC, HOAPS2, NCEP1, NCEP2, ERA40 and OAFLUX) are compared with each other to check the quality of datasets. All products reveal a similar pattern in the averaged fields of that the LHF are high in the north SCS while low in the south part. The 6-yr mean structure difference fields of latent heat fluxes between HOAPS2, NCEP1, NCEP2, ERA40 and SOC show that the overestimation are 5~10,10~30,20~35 and 15~25Wm-2,repectively. The region of highly overestimation is from 10oN to 12oN for the four datasets. WHOI OAFLUX shows the most similar pattern with SOC. For sensible heat fluxes, we found that the overestimations of HOAPS2, NCEP1, ERA40 and OAFLUX to SOC are 2~3Wm-2,2~5Wm-2,2~7Wm-2,1~4Wm-2,resptivly. NCEP2 overestimate the SHF 1~4 Wm-2 in the north SCS and underestimate 1~4 Wm-2 in the south. The yearly mean fields of turbulent heat fluxes over the whole SCS show that the LHF of OAFLUX is the most close to SOC and the differences between HOAPS2 and SOC are small except in 1990. The LHF products based on NWP outputs are all overestimated compared to SOC, especially NCEP2 and ERA40. As far as the time changes of SHF are concerned, the absolute differences are small for all products, but the relative differences are large. SHF of NCEP2 and OAFLUX hold the best agreement with SOC and ERA40 give the worst. The comparison of zonal averages of 6-yr(1988-1993) latent and sensible heat fluxes from all six datasets show the basic pattern of high value in the north and low in the south and there is a local maximum near 10oN.The widely used turbulent heat fluxes in the NCEP2 are evaluated using three...