简介:Basedontheassumptionofglobalsealevelrisingbetween30and100cminthefuture100yearsbyIPCC(1990)inadditiontotheeffectoflocalgroundsubsidence,thecoastlinewillretrogradefor50-70kmwhosealtitudeswillbe2.6-3.3maboveMSLofHuanghaiSeainthewesterncoastalareaoftheBohaibayin2100.Thetransgrassiveareaisabout10,000-11,500km.Iftheeffectofset-upofstormsurgeisconsidered,thetransgressiveareawillreach16,000km.Sealevelrisewhichisaseriouscoastaldisasternotonlyinundatesalotofcoastallowland,butalsoincreasesthefrequencyandintensityofstormtides,andresultsinthesalinizationofsoils.Inviesofthissituationwerecommendatrinitycomprehensivemeasureoftreatment,namely,"buildingseawalltopreventtides-divertingtheHunagheRivertosettleitssedimentloads-raisingtheconstructionalbase".
简介:Extremewaterlevelisanimportantconsiderationwhendesigningcoastalprotectionstructures.However,frequencyanalysisrecommendedbystandardcodesonlyconsiderstheannualmaximumwaterlevel,whereaswaterlevelsshouldactuallyberegardedasacombinationofastronomicaltideandstormsurge.Thetwoimpactingfactorsarebothrandomvariables,andthispaperdiscussestheirdependencystructuresandproposesanewjointprobabilitymethodtodetermineextremedesignwaterlevels.Thelognormal,Gumbel,Weibull,Pearsontype3,traditionalmaximumentropy,andmodifiedmaximumentropydistributionsareappliedtofitunivariatedataofastronomicaltidesandstormsurgesseparately,andthebivariatenormal,Gumbel-Hougaard,FrankandClaytoncopulasarethenutilizedtoconstructtheirjointprobabilitydistributions.Toensurethatthenewdesignmethodissuitableforusewithtyphoondata,theannualoccurrencefrequencyoftyphoonprocessesisconsideredandcorrespondingbivariatecompoundprobabilitydistributionsareproposed.BasedonmaximumwaterleveldataobtainedfromHengmenhydrologicalstationinthePearlRiverBasin,China,theseprobabilitymodelsareappliedtoobtaindesignsforextremewaterlevelsusingthelargestsumoftheastronomicaltideandstormsurgeobtainedunderfixedjointreturnperiods.Thesedesignvaluesprovideanimprovedapproachfordeterminingthenecessaryheightofcoastalandoffshorestructures.
简介:BasedonthesimulationwiththeOcean-AtmosphereCoupledModelCCSMandOceanModelPOPunderthegreenhousegasemissionscenariooftheIPCCSRESA2(IPCC,2001),andontheearthcrustsubsidenceandglaciermeltingdata,therelativesealevelchangeisobtainedalongthecoastofChinainthe21stcentury.UsingtheSRTMelevationdatathesubmergenceofcoastallowlandiscalculatedundertheextremewaterlevelwitha100-yearreturnperiod.Thetotalfloodingareasare98.3×103and104.9×103km2for2050and2080,respectively.Forthethreeregionsmostvulnerabletoextremesealevelrise,i.e.,thecoastofBohaiBay,theYangtzeRiverDeltatogetherwithneighboringJiangsuProvinceandnorthernZhejiangProvince,andthePearlRiverDelta,thefloodedareasare5.0×103,64.1×103and15.3×103km2in2050and5.2×103,67.8×103and17.2×103km2in2080,respectively.
简介:two-time-level,三维的数字海洋发行量模型(命名MASNUM)与一个二水平的、单个步的Eulerian提交向后时差计划被建立。大规模海洋的运动的一个数学模型基于协调的地面追随者,Boussinesq,海洋动力学的平均Reynolds的原始方程。一个简单却很实际的Eulerian提交向后方法被采用为barotropic和baroclinic模式作为时差方法代替大多数比较喜欢的跳蛙游戏计划。提交向后方法具有精确性的秒顺序,由每时间步要求一仅仅功能评估计算地有效,并且没有在三水平的计划固有的计算模式。这个方法比跳蛙游戏计划优异因为稳定性的最大的时间步骤这样象在蹒跚的网孔的跳蛙游戏计划的一样两次大计算效率能被加倍。一个空间变光滑方法被介绍在数字集成控制非线性的不稳定性。模仿赤道的Rossbysoliton的繁殖的一个理想的数字实验被执行测试振幅和这个新模型的阶段错误。这个发行量模型的表演进一步被验证与一地区性(西北太平洋)并且一伪全球(有排除的北极海洋的全球海洋模拟)模拟实验。这二个数字实验与观察显示出相当好的同意。在这二个实验的稳定性的最大的时间步也在采用跳蛙游戏计划的这个模型和那个模型之间被调查并且比较。
简介:整体最佳的插值(EnOI)被用于与吸收沿着轨道海水平异例(TSLA)的能力为系统(ROMS)建模的地区性的海洋。这个系统与华南海(SCS)的一个解决旋涡的系统被测试。背景错误从一变季节被导出在SCS以内说明季节的可变性的整体。有250km本地化半径的第五顺序的本地化功能被选择减少采样错误的否定效果。数据吸收系统从2004年1月被测试到2006年12月。结果证明根意味着海水平异例的方形的偏差(RMSD)从10.57~6.70厘米减少了,它代表错误的36.6%减小。为在内的温度的数据吸收还原剂错误上面800m并且为在内的咸度上面200m,尽管错误在更深的深度稍微降级。表面水流在对在数据吸收以后的表面流浪者的轨道的更好的同意。海水平的变化在吸收TSLA以后以强壮、弱的变化区域的振幅和位置显著地改善。当考虑温度和咸度的改进时,有年龄错误(年龄)的结果比没有年龄错误(NoAGE)更好表现。而且,在高分辨率在北SCS为极其强壮的可变性推想模型被调查。结果证明在高分辨率模型的海水平的强壮的可变性被极其强壮的自台湾东面的菲律宾海流向日本的暖流侵入引起。因此,吸收TSLA以便更好与高分辨率模型一起模仿SCS是必要的,这被表明。
简介:ViathevaluableopportunityoftheThreeGorgesReservoir(TGR)135-mfillinginJune2003,theYangtzedischargeandsuspendedsedimentconcentration(SSC)enteringtheestuaryduringtheperiodfrom15Mayto15July2003wereanalyzedtoexaminetheinstanteffectsofthefillingonthem.TheYangtzedischargeandSSCenteringtheestuaryintheperiodsbefore,duringandafterthefillingclearlyindicatedthreephases:1)thepre-storagephasecharacterizedbynaturalconditions,inwhichtheSSCincreasedwithincreasingwaterdischarge;2)thestoragephase,duringwhichtheSSCdecreaseddramaticallywithdecreasingwaterdischarge;and3)thepost-storagephase,duringwhichboththeSSCandwaterdischargeremainedatrelativelylowlevelsfirstuntiltheendofJune,thentheSSCincreasedgraduallywithincreasingwaterdischarge.ItseemsthatthetimesfortheinstanteffectsofthedecreasingdischargedownstreamfromtheupperYangtzeontheYangtzedischargeandSSCenteringtheestuaryduetotheTGR135-mfillingtotakeplacewereabout5dand1drespectively,whilebothwereabout18dforthoseoftheincreasingdischarge.Thisprobablyreflectsthebufferingandresultantlyhysteresisofthe1800-kmstretchfromtheupperYangtzetotheestuary.TheresultsarehelpfulforscientificandhydrologicalinvestigationoftheYangtzemainstreamdownstreamfromtheTGRDamandoftheestuarineandadjacentcoastalwaters.