海洋性大陆地形对夏季季节内振荡的影响:基于2020年9月个例的数值模拟分析OA北大核心CSTPCD

Maritime Continent(MC)may interfere the propagation of BSISO(the Boreal Summer IntraSeasonal Oscillation).In this study,the Weather Research & Forecast(WRF)model is used to simulate the BSISO event observed in the area around MC during the period of August-September,2020.To study the influence of the topography of the MC on the propagation and intensity of this BSISO event,the topography of the MC is flattened in the WRF model,and a sensitivity experiment is conducted for comparison with the control experiment.The WRF control simulation shows the low-level wind similar to this in ERA5,as well as a northwest-southeast tilted rain band as observed BSISO,indicating that the control experiment reasonably captures the mean state and propagation characteristics of this BSISO event.Eliminating the topography around the MC region in the sensitivity experiment results in stronger low-level wind and smoother propagation.There is a significant increase in water vapor and a decrease in precipitation around the MC islands.The zonal advection is greatly enhanced,thus enhancing the convection over the ocean and promoting propagation of this BSISO.The results suggest substantial impact of the MC island on the structure and propagation of the BSISO.