简介：Thegeophysicalmodelfunction(GMF)describestherelationshipbetweenbackscatteringandseasurfacewind,sothatwindvectorscanberetrievedfrombackscatteringmeasurement.TheGMFplaysanimportantroleinoceanwindvectorretrievals,itsperformancewilldirectlyinfluencetheaccuracyoftheretrievedwindvector.Neuralnetwork(NN)approachisusedtodevelopaunifiedGMFforC-bandandKu-band(NN-GMF).EmpiricalGMFCMOD4andQSCAT-1areusedtogeneratethesimulatedtrainingdata-set,andGaussiannoiseatasignalnoiseratioof30dBisaddedtothedata-settosimulatethenoiseinthebackscatteringmeasurement.TheNN-GMFemploysradiofrequencyasanadditionalparameter,soitcanbeappliedforbothC-bandandKu-band.Analysesshowthattheσ0predictedbytheNN-GMFiscomparablewiththeσ0predictedbyCMOD4andQSCAT-1.AlsothewindvectorsretrievedfromtheNN-GMFandempiricalGMFCMOD4andQSCAT-1arecomparable,indicatingthattheNN-GMFisaseffectiveastheempiricalGMF,andhastheadvantagesoftheuniversalform.

简介：Permittivityofaseafoamlayerisveryimportantininvestigatingoceanbrightnesstemperaturemodel.Atmicrowavefrequency,theRayleighmethodisdevelopedtoestimatetheeffectivepermittivityoftheseafoamlayer.TosimplifythetediouscalculationofseafoameffectivepermittivityatLband(1.4GHz),Pade’approximationisadoptedtofittheseafoameffectivepermittivitycomputedbytheRayleighmethod.Withthisfittingformula,anewbrightnesstemperaturemodelofseafoamlayerdefinedbycertaingeophysicalparameters,suchasairvolumefraction(AVF),seasurfacetemperature(SST),seasurfacesalinity(SSS)andthicknessoffoamlayerd,isgiven.Furthermore,thesensitivitiesofthebrightnesstemperaturemodeltoSST,SSS,dandAVFofaseafoamlayeratLbandarediscussed.Thesensitivitiesarerankedfrommosttoleastintheorder:(1)d;(2)AVF;(3)SSS;(4)SST.ThisresultindicatesthatthemeasurementerrorsofdandAVFhavesignificantimpactsontheretrievalsofSSSandSST.Withtheexperimentalbrightnesstemperaturedata,theSSSandAFVareretrievedbycostfunction.

简介：Afatiguelifeestimationmethodforoffshorestructuresunderrandomstressresponseisstudiedinthispaper.Themethodofbroadbandcumulativefrequencynumberisusedtodeterminetheeffectofbandwidthofstressfrequencyspectraonfatigue.AformulaofcorrectionfactorforfatigueunderbroadbandstressspectraissuggestedandcomparedwiththatgivenbyP.H.Wirsching.

简介：传统卫星测高数据处理中共线平差的精度极大影响最终解算结果,针对经初步处理后卫星测高数据仍可能存在粗差的问题,提出一种融合抗差的共线秩亏平差算法.该算法结合传统共线平差及抗差估计的优点,保留了秩亏自由网平差不需要基准控制点的优良性质,并有效地剔除秩亏自由网中存在的粗差,实现更高精度的解算结果.实验表明,相比较传统共线秩亏平差算法而言,提出的算法解算结果精度更高.

简介：考虑观测仪器系统参数以及异常观测数据对参数估值的影响,讨论了平差中系统参数、重力基准的选择,并采用抗差剔除或削弱异常观测数据的影响,采用实际观测数据进行了试算.