简介:ToretrievewindfieldfromSARimages,thedevelopmentforsurfacewindfieldretrievalfromSARimagesbasedontheimprovementofnewinversionmodelispresent.GeophysicalModelFunctions(GMFs)havebeenwidelyappliedforwindfieldretrievalfromSARimages.AmongthemCMOD4hasagoodperformanceunderlowandmoderatewindconditions.AlthoughCMOD5isdevelopedrecentlywithamorefundamentalbasis,ithasambiguityofwindspeedandashapegradientofnormalizedradarcrosssectionunderlowwindspeedcondition.ThisstudyproposesamethodofwindfieldretrievalfromSARimagebycombiningCMOD5andCMOD4FiveVV-polarisationRADARSAT2SARimagesareimplementedforvalidationandtheretrievalresultsbyacombinationmethod(CMOD5andCMOD4)togetherwithCMOD4GMFarecomparedwithQuikSCATwinddata.Theroot-mean-squareerror(RMSE)ofwindspeedis0.75ms-1withcorrelationcoefficient0.84usingthecombinationmethodandtheRMSEofwindspeedis1.01ms-1withcorrelationcoefficient0.72usingCMOD4GMFaloneforthosecases.TheproposedmethodcanbeappliedtoSARimageforavoidingtheinternaldefectinCMOD5underlowwindspeedcondition.
简介:ToinvestigatetheannualandinterannualvariabilityofoceansurfacewindovertheSouthChinaSea(SCS),thevectorempiricalorthogonalfunction(VEOF)methodandtheHilbert-Huangtransform(HHT)methodwereemployedtoanalyzeasetofcombinedsatellitescatterometerwinddataduringtheperiodfromDecember1992toOctober2009.ThemergedwinddataweregeneratedfromEuropeanRemoteSensingSatellite(ERS)-1/2Scatterometer,NASAScatterometer(NSCAT)andNASA'sQuickScatterometer(QuikSCAT)windproducts.ThefirstVEOFmodecorrespondstoawinter-summermodewhichaccountsfor87.3%ofthetotalvarianceandrepresentstheEastAsianmonsoonfeatures.ThesecondmodeofVEOFcorrespondstoaspring-autumnoscillationwhichaccountsfor8.3%ofthetotalvariance.Toanalyzetheinterannualvariability,theannualsignalwasremovedfromthewinddatasetandtheVEOFsoftheresidualswerecalculated.ThetemporalmodeofthefirstinterannualVEOFiscorrelatedwiththeSouthernOscillationIndex(SOI)withafour-monthlag.ThesecondtemporalinterannualVEOFmodeiscorrelatedwiththeSOIwithnotimelag.ThetimeseriesofthetwointerannualVEOFsweredecomposedusingtheHHTmethodandtheresultsalsoshowacorrelationbetweentheinterannualvariabilityandElNi?o-SouthernOscillation(ENSO)events.
简介:雨效果和缺乏在situ确认,数据是热带气旋风检索错误的二个主要原因。国家海洋、大气的政府气候预言中心Morphing技术(CMORPH)雨率被介绍给配对数据集然后放进一个雨修正模型在Jason-1上移开雨效果规范的雷达十字节(NRCS);飓风研究部门(HRD)风速度,集成所有可得到的表面天气观察,被用来在situ数据代替与Jason-1NRCS建立这种关系。然后,在热带气旋条件下面的一个改进Jason-1风检索算法被建议。从2003~2010的七热带气旋被学习验证新算法。试验性的结果显示在C乐队和Ku乐队的这个算法的标准差分别地是1.99和2.75m/s,它比存在算法好。另外,C乐队算法比在热带气旋条件下面的Ku乐队对海表面风检索更合适。
简介:ThecentralPacific(CP)zonalwinddivergenceandconvergenceindicesaredefined,andtheformingmechanismofCPElNio(LaNia)eventsisdiscussedpreliminarily.Theresultsshowthatthedivergenceandconvergenceofthezonalwindanomaly(ZWA)arethekeyprocessintheformingofCPElNio(LaNia)events.AcorrelationanalysisbetweenthecentralPacificzonalwinddivergenceandconvergenceindicesandcentralPacificElNioindicesindicatesthatthereisaremarkablelagcorrelationbetweenthem.ThecentralPacificzonalwinddivergenceandconvergenceindicescanbeusedtopredicttheCPevents.Basedontheseresults,alinearregressionequationisobtainedtopredicttheCPElNio(LaNia)events5monthsahead.
简介:A3D为Sutong留下来电缆线的桥(SCB)的有限元素(FE)模型基于ANSYS被建立。桥的动态特征用一个subspace重复方法被分析。基于记录的风数据,测量系列表达式用非线性的最少平方的回归方法被介绍。在桥地点的狂暴的风被模仿基于光谱表示方法和快速傅里叶变换技术。桥的动态特征上的一些关键结构的参数和措施的影响被调查。这些参数包括死了的负担紧张,以及钢盒子girder的垂直、侧面、扭力的僵硬。另外,在钢盒子girder的颤动模式上在塔和girder之间采用的连接设备的有弹性的僵硬的影响被调查。分析证明垂直、侧面、扭力的buffeting排水量,回答作为死者逐渐地减少的所有装载紧张增加。动态特征和SCB的结构的buffeting排水量反应被钢盒子girder的垂直、扭力的僵硬仅仅稍微影响,并且当侧面的僵硬增加,侧面、扭力的buffeting排水量回答逐渐地减少。这些结果为动态分析提供一本参考书并且super-long-span设计留下来电缆线的桥。