XGM2019e_2159.gfc

XGM2019e_2159.gfc
XGM2019eisacombinedglobalgravityfieldmodelrepresentedthroughspheroidalharmonicsuptod/o5399,correspondingtoaspatialresolutionof2’(~4km).AsdatasourcesitincludesthesatellitemodelGOCO06sinthelongerwavelengthareacombinedwithterrestrialmeasurementsfortheshorterwavelengths.TheterrestrialdataitselfconsistsoverlandandoceanofgravityanomaliesprovidedbycourtesyofNGA(identicaltoXGM2016,havingaresolutionof15’)augmentedwithtopographicallyderivedgravityoverland(EARTH2014).Overtheoceans,gravityanomaliesderivedfromsatellitealtimetryareused(DTU13,inconsistencywiththeNGAdataset).Thecombinationofthesatellitedatawiththeterrestrialobservationsisperformedbyusingfullnormalequationsuptod/o719(15’).Beyondd/o719,ablock-diagonalleast-squaressolutioniscalculatedforthehigh-resolutionterrestrialdata(fromtopographyandaltimetry).Allcalculationsareperformedinthespheroidalharmonicdomain.Inthespectralbanduptod/o719thenewmodelshowsoverlandaslightlyimprovedbehavioroverprecedingmodelssuchasXGM2016,EIGEN6c4orEGM2008whencomparingittoindependentGPSlevelingdata.Overlandandinthespectralrangeaboved/o719theaccuracyofXGM2019eslightlysuffersfromthesoleuseoftopographicforwardmodelling;Hence,errorsareincreasedinwell-surveyedareascomparedtomodelscontainingrealgravitydata,e.g.EIGEN6c4orEGM2008.However,theperformanceofXGM2019ecanbeconsideredasgloballymorehomogeneousandindependentfromexistinghighresolutionglobalmodels.Overtheoceansthemodelexhibitsanimprovedperformancethroughoutthecompletespectrum(equalorbetterthanprecedingmodels). 本软件ID:12559204