Sensitivity Of East Asian Offshore Tropical Cyclones Simulations To Physical Parameterization Schemes

As one of the most active tropical cyclone(TC)domains,27 TCs occur in the Northwest Pacific basin every year.In recent years,as a main means of TC forecast,numerical simulation is widely used in the studies of TC climatology.However,there is still great uncertainty in simulation of climatological TC activities by numerical models while the impact of physical parameterizations schemes on TC simulation is still not clear.The possible effect of cumulus(CU),micro-physics(MP)and planetary boundary layer(PBL)physical parameterization schemes on simulated TC tracks,frequencies and intensities over East Asian offshore during 1986?2015 has been investigated respectively by using the regional Climate-Weather Research and Forecasting model(CWRF).The main conclusions are as follows:1)Simulations with the CWRF model produced weaker intensities and less strong TC numbers than observations';Less TC numbers are simulated in most years while the frequency distribution in different months is similar with the observation's;TC active domain in the area of north to the Philippines can be found in most schemes while TCs over South China Sea are poorly simulated.2)Significant difference of TC intensities,frequencies and spatial distribution can be found between the CU schemes.Simulations with the KF scheme produced stronger intensities,more TC numbers,better spatial distribution and higher TS scores than others.Thus,the performance of TC frequencies,tracks and intensities simulations with the KF scheme can be found better than the other CU schemes in CWRF model.3)Significant difference of TC frequencies and spatial distribution can be found between the MP schemes while discrepancies of simulated TC intensities are not obvious.Simulations with the GCE scheme produced stronger intensities,more TC numbers,better spatial distribution and higher TS scores than others.Thus,the performance of TC frequencies,tracks and intensities simulations with the GCE scheme can be found better than the other MP schemes in CWRF model.In addition,improvement of simulated frequencies and spatial distribution can be found under the consideration of aerosol.4)Great difference of TC intensities,frequencies and spatial distribution can be found between the PBL schemes.Simulations with the CAM3 scheme produced stronger intensities,more TC numbers,better spatial distribution and higher TS scores than others.Thus,the performance of TC frequencies,tracks and intensities simulations with the CAM3 scheme can be found better than the other PBL schemes in CWRF model.5)Influence on simulated TC frequencies,intensities and spatial distribution can befound greatest with CU schemes,second place taken by PBL schemes and third place taken by MP schemes.The conclusions in this study can not only provide basis for CWRF simulation and forecast TC activities but also help choose suitable schemes for East Asia offshore TCs' simulations from different physical parameterizations.