北南海內(nèi)波波動(dòng)模擬

北南海內(nèi)波波動(dòng)模擬陳冠宇、吳瑞中、王玉懷國(guó)立中山大學(xué)海下科技暨應(yīng)用海洋物理研究所SouthChinaSea(SCS)isfamousforlargeamplitudeinternalwavesLiuandHsu,2004FieldmeasurementbyProf.Y.H.WangA#01116.55.053E20.43.974N環(huán)礁

直徑25公里環(huán)礁內(nèi)最深約16公尺東沙島長(zhǎng)3公里寬1公里面積1.74平方公里實(shí)測(cè)觀測(cè)資料顯示，當(dāng)內(nèi)波通過(guò)東沙環(huán)礁時(shí)，海水溫度下降約有6~8度，且湧昇上來(lái)的冷水時(shí)間約有4小時(shí)之久。但南海的內(nèi)波時(shí)間尺度大約是15分鐘(AccordingtoA.K.Liuetal.,2004,internalsolitarywaveinwestSCShaswidth1.6kmandwavespeed1.8m/s;InternalsolitarywaveineastSCShaswidth3kmandwavespeed3m/s)其時(shí)間尺度比東沙冷水事件的過(guò)程短許多，因此為更進(jìn)一步了解其物理過(guò)程，有必要進(jìn)行詳細(xì)的數(shù)值模擬。

2DBoussinesqtypemodelisnotapplicableModelSetupforPOMDomain:116.875°E~117.025°E20.65°N~20.8°NGridsize:100m150*150*30SimulationPeriod:2daysOutput:every30secondsThein-situstratificationmeasuredat300mdepthintheeastofDongsha

isusedastheinitialstate.ThemodelisdrivenbytheflowboundaryconditionintheeastSynolakisfoundhydrostaticmodelissuitablefortherun-upoftsunamiPOMishydrostaticandissuitablefortherun-upproblem120BathymetryisprovidedbytheTaiwanOceanResearchInstitute1.Thein-situstratificationisusedtogetthebuoyancyfrequencyN

2.distributionofNisusedtoobtaintheeigenmodeforw

3.VerticaldistributionofuisusedastheboundaryconditionVariationintimeisdeterminedbytheKdVsolitonsolutionFlowBoundaryConditionsforISWstheKdVtheoryisbasedontheinviscidassumptionwhichisnotcompatiblewithPOM.Besides,theISWpropagateswithanetmasstransport,buttheeigenmodeassumeszeronetfluxTheverticalflowboundaryconditionneedstobemodifiedbyartificiallyshiftingthealtitudeofzero-flow.Afteranumberofexperimentsontheshiftingaltitude,ISWscanbegeneratedwithsomerippleslagbehind.NearDongsha,acoupleofsuccessiveinternalwavesareobserved在東沙東方製造三個(gè)波OriginallytherearethreeISWs原本三個(gè)波Threewavesmergeintoone

結(jié)合成一個(gè)波由於環(huán)礁外海淺水處的臺(tái)階地形使冷水停留在臺(tái)階上Aftertherunupofthesurge,itrecedeoffshorepromptlyiftheshelfdoesnotexist環(huán)礁外海淺水處的臺(tái)階地形使冷水停留在臺(tái)階上，更進(jìn)一步延長(zhǎng)冷水事件的時(shí)間Discussionsonthewaveform當(dāng)內(nèi)波進(jìn)入大陸斜坡時(shí)，波形變成非對(duì)稱的前陡後緩波形內(nèi)波若以湧波