The surroundings of the Bay of Bengal(Bo B)suffer a lot from the extreme rainfall events during Indian summer monsoon(ISM).Previous studies have proved that the sea-air interaction is an important factor for the monso...The surroundings of the Bay of Bengal(Bo B)suffer a lot from the extreme rainfall events during Indian summer monsoon(ISM).Previous studies have proved that the sea-air interaction is an important factor for the monsoonal precipitation.Using the 6th Coupled Modol Inter-comparison Project(CMIP6)models,this study examined the biases of surface heat flux,which is the main connection between atmosphere and ocean.Results show that although CMIP6 have a better simulation of intraseasonal sea surface temperature(SST)anomalies over Bo B than the previous ones,the“atmospheric blockage”still delays the response of latent heat flux to the oceanic forcing.Specifically,during the increment of positive latent heat flux in CMIP6,the negative contribution from wind effects covers most of the positive contribution from humidity effects,due to the underestimate of humidity effects.Further diagnostic analysis denote that the surface air humidity has a quarter of a phase ahead of warm SST in observation,but gets wet along with the warm SST accordingly in most CMIP6 models.As a result,the simulated transfer of intraseasonal moisture flux is hindered between ocean and atmosphere.Therefore,as a bridge between both sides,the atmospheric boundary layer is essential for a better sea-air coupled simulation,especially when the atmospheric and the oceanic variabilities involved in a climate model becomes increasingly sophisticated.The surface air humidity and boundary layer processes require more attention as well as better simulations.展开更多
基金The National Natural Science Foundation of China under contract Nos 42076001 and 42106003the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources under contract No.JB2206。
文摘The surroundings of the Bay of Bengal(Bo B)suffer a lot from the extreme rainfall events during Indian summer monsoon(ISM).Previous studies have proved that the sea-air interaction is an important factor for the monsoonal precipitation.Using the 6th Coupled Modol Inter-comparison Project(CMIP6)models,this study examined the biases of surface heat flux,which is the main connection between atmosphere and ocean.Results show that although CMIP6 have a better simulation of intraseasonal sea surface temperature(SST)anomalies over Bo B than the previous ones,the“atmospheric blockage”still delays the response of latent heat flux to the oceanic forcing.Specifically,during the increment of positive latent heat flux in CMIP6,the negative contribution from wind effects covers most of the positive contribution from humidity effects,due to the underestimate of humidity effects.Further diagnostic analysis denote that the surface air humidity has a quarter of a phase ahead of warm SST in observation,but gets wet along with the warm SST accordingly in most CMIP6 models.As a result,the simulated transfer of intraseasonal moisture flux is hindered between ocean and atmosphere.Therefore,as a bridge between both sides,the atmospheric boundary layer is essential for a better sea-air coupled simulation,especially when the atmospheric and the oceanic variabilities involved in a climate model becomes increasingly sophisticated.The surface air humidity and boundary layer processes require more attention as well as better simulations.
