Numerical Study Of The Effects Of Climate Change On Typhoon Storm Surge And Inundation In Yangtze Estuary

China is one of the countries most affected by typhoon in the world.The storm surge disaster caused by strong typhoon is still severe.With the gradual progress of climate change,the impact of such disasters may be further improved.Under such circumstances,for adjusting the flood control system,improving the capacity of disaster prevention and reducing the losses caused by typhoon,it is of great significance to carry out the research on the impact of climate change on typhoon,storm surge and flood.The impacts of climate change need to be demonstrated by a credible wind and hydrodynamic coupling model.The coupling model is the basis of the research,and it can also provide technical support for related research.Therefore,it is of great theoretical and practical significance to figure out the typhoon,storm surge and flood changes caused by climate change.In this paper,based on the WRF-ADCIRC coupling model,the landing typhoon Matsa,No.0509,and typhoon Chan-Hom,No.1509 without landing,which affected the Yangtze River estuary,were selected as cases for simulation.At the same time,from the three aspects of the selection of simulation parameters,sea surface temperature data and underlying surface data,this paper optimized the WRF wind field.Under the background of climate change,the effects of sea surface temperature rise on typhoon and storm surge in the Yangtze estuary was studied.Taking Shanghai as a case,the effects of sea surface temperature rise and sea level rise on flood was studied.The main contents and conclusions of the study are as follows:(1)5 typical microphysical parameters and cumulus parameterization schemes were selected for sensitivity experiments of typical typhoons in the Yangtze River Estuary.Through the analysis of the results,the two parameters have similar influence on the wind speed of the verification point.For typhoon track,the influence of microphysics parameterizations is smaller.For typhoon Matsa WSM3 + New SAS is the appropriate combination of parameters,and for typhoon Chan-hom,WSM3 + Grell is more appropriate.Therefore,in Yangtze River Estuary,WSM3 is suggested.On this basis,the wrf-adcirc coupling model was established.The model can well simulate the water level during typhoon.(2)Based on selected typhoons,SSTR increases the intensity of typhoon,and the trend of typhoon is far away from land.The track of typhoon Matsa shows the trend of turning ahead of time,and that of typhoon Chan-hom moves eastward and deviates from the land.When the SSTR is 2.10?,the maximum wind speed will increase by 10%,and for 4.25?,it will increase by 25%.(3)Based on selected typhoons,for most regions,the max storm surge increases,especially the coastal areas of Jiangsu and Shanghai,and the effect on nearshore is more obvious.Typhoon Matsa improves the max storm surge a lot in Zhejiang coast area.But it has little effert on the max storm surge in Hangzhou Bay.The influence of typhoon Chan-hom on the max storm surge is mainly in the coastal area of Jiangsu Province.When SSTR is 2.10 ?,the max storm surge of typhoon Matsa in the Yangtze Estuary increases by 0.2-0.4m,and increases by 0.3-0.5m at 4.25 ?.The results of typhoon Chan-hom are 0-0.2m and 0.3-1.0m.(4)Using WRF-ADCIRC coupling model and high tide level to simulate flood,the flood corresponds to the distribution of max storm surge,taking Shanghai as an example.With the advancement of SSTR and SLR,the flood range has been significantly improved.The results show that Chongming Island,Jiuduansha island and other islands is low,and the flood is serious.The elevation in the east of Shanghai is relatively low,there will be large range of flood.In the south,only under the influence of typhoon Matsa,there will be large flood,while the situation of flood caused by the typhoon Chan-hom is relatively light.