Simulate Storm Surge Of Typhoon On The Northern Of The South China Sea And Explore Mechanism

In coastal areas, storm surge made a large of disaster, which was NO.1in themarine disasters on social and economic losses. Typhoon and Storm surge affectedfrequently China, especially at South China Sea. Hence, effective forecasting andmechanism researching is necessary for storm surge of typhoon at north of the SouthChina Sea. Based on the above concept, we had modeled typical storm surge at northof South China Sea, explored mechanism and haven some conclusion.A model of wind field was established and corrected which used similarity theory.In the process of building wind model, we found that circular symmetry wind field ofDUAL had adjustable parameters and appropriate researched on typhoon at north ofSouth China Sea; model of typhoon was impacted on temperature and velocity ofwind when inflow angle was corrected by using Fujita formula; when adding movingwind along typhoon track on model, model of typhoon would show the right windvelocity was larger which more closed to real typhoon; adding background windwhich using formulation on model of typhoon wound make to increase surge near thecenter of typhoon and far from typhoon, but reduce surge near around the maximumsurge point.Storm surge was simulated by the previous model of typhoon and verified bydata from Hong Kong Observatory and AVISO. The results which contrasted betweensimulation and data from Hong Kong Observatory data, showed that the simulationwas satisfying, when neglecting surge increased by pressure and remote atmospheric.However, the results which contrasted between simulation and data from AVISO’sdata, found the simulation was accurate only when measuring data of AVISO on farfrom land and boundary.Surge oscillation was classified by location on typhoon, which characteristic anddegree of attention was indicated. We also found classified by location on typhoonmore reasonable than by time before landed.We researched variety of position of maximum surge, level of surge and time oflag under wind of different factor. It was found which position of maximum surgelocated right of typhoon and distanced from the typhoon center about twice the radiusof maximum wind by using test of finding maximum point and test of changingtyphoon trace to determine maximum surge point. Then, contrasting surge test under wind of different factor showed that more fast moving typhoon made less positive andnegative storm surge. With larger inflow angle, positive storm surge increased andnegative storm surge receded near typhoon landed, but positive storm surge was aslight decrease far from center of typhoon. Positive storm surge wound increase alittle when the same of all velocity, but was large at point of typhoon landed. Withbigger radio of maximum wind, positive and negative storm surge wound increase,especially around point of typhoon landed. In the standing on point of typhoon landedtest, we found the maximum surge of landing moments was not caused by thetyphoon of landing moment and surge had a little of periodicity. Finally, using changetyphoon moving speed method，we separated time and position of typhoon andresearched characteristic which surge lagged wind. The result showed that surgewhich caused by “Hagupit” typhoon, lagged wind about3h and position of typhoonwhich making maximum surge of landing moment, located from land about twice theradius of maximum wind. The reason should be correlation between the position ofthe point of maximum surge and the typhoon center.Positive storm surge increased a little due to variation of vertical temperature.Tide interacted with surge showed that storm surge was the main of total sea level inthe typhoon main shock stage and surge was diverse in the remaining stages.Nonlinear interaction with tide and surge showed that storm surge increased more inebb period than in flood period. Nonlinear interaction made surge reduced in thetyphoon main shock stage and surge diversity in the remaining stages. Spatialdistribution of nonlinear interaction when landing of typhoon showed it was negativearound center of typhoon and variation in the remaining place. However, nonlinearinteraction was a large positive value on estuary area due to effecting of topography.