Numerical Simulation And Verification Of Typhoon Wind Field By WRF Mesoscale Model

Typhoon is a relatively common major natural disaster,which has a great impact on people's lives and production.There are about ten typhoon's landing in the coastal areas of China,the damage and destruction from the typhoon is great.Therefore there is urgent need to conduct the research studies on the characteristic of typhoon wind field in wind engineering field.The research work about typhoon in meteorology area mainly concentrates on the whole life process of typhoon,including its generation,development and extinction.In the civil engineering field,research work may focus on the numerical simulation of typhoon wind field by simple parametric physical model and mesoscale model.Some wind field parameters such as central pressure ? moving speed of typhoon and central radius of typhoon,and other parameters such as wind speed and wind direction around the structure are obtained from the simulation analysis.These data would be helpful to the wind resistant design of tall building structures.The Weather Research and Forecasting(WRF)mesoscale model is ultilized in this dissertatation to conduct the numerical simulation and verification of typhoon wind field.The basic theory related with the WRF system was first introduced.The main numerical simulation models and their functions,the adopted grid model and some key parameters related with physical process for numerical simulation in WRF system are described.The WRF model adopts the most comprehensive atmospheric physical process and more optimized dynamic framework.The boundary layer scheme and cumulus convection parameterization scheme have great influence on simulation results for different types of typoons and typhoons in different regions.Therefore,the the Advanced Research WRF(ARW)module in WRF system is adopted in this dissertation to simulate and analyze 9914 typhoon “York” and 1713 typhoon “pigeon” by making different combinations of boundary layer scheme and cumulus convection parameterization scheme.The numerical simulation data for the wind fields of two typhoons were compared with those measured datum from Tropical Cyclone data Center of China Meteorological Administration(CMA)and Hong Kong Observatory Station.The feasibility of WRF mesoscale model to simulate typhoon is verified from the compared analysis data on the typhoon path,central air pressure and maximum wind speed.Meanwile the strategies on how to select the suitable boundary layer scheme and cumulus convection parameterization scheme in typoon simulation are also discussed.Based on the most suitable combination scheme on physical process,the WRF system is adopted in wind field simulation on typoon “York” and “pigeon”.The numerical simulation data such as wind speed,wind dirctions and wind profile index for typhoon field at some tall buildings(Li Tong square in Guangzhou and Di Wang Tower in Shenzhen)and weather observation stations in Hongkong were extracted and compared with those corresponding measured data from the observation stations in boundary layer.The analysis results show that WRF mesoscale model could simulate the wind speed and direction of both tall and low–rise building immersed in typhoon condition with acceptable accuary.Finally,the numerical simulated datum such as wind speed and wind direction for typhoon “York” and “pigeon” wind field were extracted and statisticalized.These analyzed results were used to verify the proposed formula from the simple parametric physical model for typhoon wind simulation.d.The results show that theose formula can basically reflect the main characteristics of wind speed data,but their function to describe the characteristics wind direction in typhoon wind field is not satisfactory.