Imprint of the ENSO on Rainfall and Latent Heating Variability over the Southern South China Sea from TRMM Observations

Analyses of the Tropical Rainfall Measuring Mission （TRMM） datasets revealed a prominent interannual variation in the convective-stratiform rainfall and latent heating over the southern South China Sea （SCS） during the winter monsoon between 1998 and 2010. Although the height of maximum latent heating remained nearly constant at around 7km in all of the years, the year-to- year changes in the magnitudes of maximum latent heating over the region were noticeable. The interannual variations of the convee- tive-stratiform rainfall and latent heating over the southern SCS were highly anti-correlated with the Nifio-3 index, with more （less） rainfall and latent heating during La Nifia （El Nifio） years. Analysis of the large-scale environment revealed that years of active rain- fall and latent heating corresponded to years of large deep convergence and relative humidity at 600hPa. The moisture budget diag- nosis indicated that the interarmual variation of humidity at 600hPa was largely modulated by the vertical moisture advection. The year-to-year changes in rainfall over the southern SCS were mainly caused by the interannual variations of the dynamic component associated with anomalous upward motions in the middle troposphere, while the interannual variations of the thermodynamic com- ponent associated with changes in surface specific humidity played a minor role. Larger latent heating over the southern SCS during La Nifia years may possibly further enhance the local Hadley circulation over the SCS in the wintertime.

Analyses of the Tropical Rainfall Measuring Mission(TRMM) datasets revealed a prominent interannual variation in the convective-stratiform rainfall and latent heating over the southern South China Sea(SCS) during the winter monsoon between 1998 and 2010.Although the height of maximum latent heating remained nearly constant at around 7 km in all of the years,the year-to-year changes in the magnitudes of maximum latent heating over the region were noticeable.The interannual variations of the convective-stratiform rainfall and latent heating over the southern SCS were highly anti-correlated with the Ni?o-3 index,with more(less) rainfall and latent heating during La Ni?a(El Ni?o) years.Analysis of the large-scale environment revealed that years of active rainfall and latent heating corresponded to years of large deep convergence and relative humidity at 600 h Pa.The moisture budget diagnosis indicated that the interannual variation of humidity at 600 h Pa was largely modulated by the vertical moisture advection.The year-to-year changes in rainfall over the southern SCS were mainly caused by the interannual variations of the dynamic component associated with anomalous upward motions in the middle troposphere,while the interannual variations of the thermodynamic component associated with changes in surface specific humidity played a minor role.Larger latent heating over the southern SCS during La Ni?a years may possibly further enhance the local Hadley circulation over the SCS in the wintertime.