Sensitivity of NCC/IAP T63 Atmosphere-ocean Coupled Model to Cloud Droplet Effective Radius
NCC/IAP T63海气耦合模式对云滴有效半径的敏感性分析

Using NCC/IAP T63 atmosphere-ocean coupled model,its sensitivity to cloud droplet effective radius is analysed.Results show that the cloud extinction optical depth changes obviously in the lower part of troposphere when interactive liquid cloud droplet radius is introduced(REL and REL_CAM3 scheme),however,optical depth shows a distinct change with different position and sign between the two schemes,and it decreases remarkably in the upper troposphere when the interactive ice cloud droplet radius(REI scheme) is used.As a result,cloud radiative forcing changes remarkably,which is mainly affected by REI scheme,and shows a decrease trend for both short and long wave radiative forcing.The global-averaged net cloud radiative forcing at top of atmosphere is more sensitive to change of ice cloud droplet radius,but they both simulate the correct sign compared to ERA-40 data although large disparities exist in magnitude.The change of net radiation at top of atmosphere is basically consistent with that of net cloud radiative forcing,generally characterized by decrease.The change of surface air temperature(TAS) shows consistent distribution basically between REL and REI scheme,that is,TAS mainly decreases in summer,and it increases obviously in the middle of Eurasian continent and north of North America.In the continent the TAS change is mainly affected by the transportation of surface heat to atmosphere,but that is inconsistent in the ocean area.When interactive liquid and ice cloud droplet radius are introduced together(RIW and RIW_CAM3 scheme),TAS shows remarkable nonlinear response(mostly locating in continental area),contrast to the quasi-linear response of optical depth and cloud radiative forcing.