《Models of isostatic and dynamic topography, geoid anomaliesand their uncertainties ,均衡和動(dòng)態(tài)地形模型，大地水準(zhǔn)面異常， 及其不確定性》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。

1、JOURNALOFGEOPHYSICALRESEARCH,VOL.105,NO.B12,PAGES28,199-28,209,DECEMBER10,2000Modelsofisostaticanddynamictopography,geoidanomalies,andtheiruncertaintiesSvetlanaV.Panasyuk?EarthandPlanetarySciences,HarvardUniversity,Cambridge,MassachusettsBradfordH.HagerEarth,Atmosp

2、hericandPlanetarySciences,MassachusettsinstituteofTechnology,Cambridge,MassachusettsAbstract.KnowledgeofthedynamictopographyatEarth'ssurfacecausedbysublithosphericdensitycontrastswouldprovidecrucialconstraintsonmodelsofmantledynamics.Wecalculateglobalmodelsofthisdy

3、namictopographybysubtractingfromtheobservedtopographyestimatesofthetopographycausedbyassumedisostaticallycompensateddensityvariationsinthecrust,theoceaniclithosphere,andthecontinentaltectosphere.Wealsocalculatetheisostaticgeoidanomalythatwouldresultfromthesecompens

4、atednear-surfacedensityanomalies.Becausethereiscontroversyaboutthethermalstructureofoldoceaniclithosphere,weinvestigatetwomodelsofthecoolingoftheoceaniclithosphere(half-spaceandplate)andcalculatetheeffectofeachontheinferreddynamictopography.Peakamplitudesofdynamict

5、opographyfi,omsublithosphericsourcesexpandedtosphericalharmonicdegree6areapproximately?1km.Weestimatetheuncertaintiesinthecalculateddynamictopographyandgeoidbycombiningtheerrorsinthedataandsystematicerrors.Toobtainthespectralcoefficientsofthefields,weuseweightedlea

6、stsquaresinversions.Thecalculateddynamictopographyarisingfromsublithosphericsources,residualgeoid,anderrorsassociatedwiththesefieldscanbeusedinstudiesofmantledynamics.1.Introductionexistenceofextensiveregionsanomalouslyshallowfortheirage(e.g.,PacificSuperswell[McNu

7、ttandFischer,1987;DaviesandEarth'ssurfacetopographyshowssubstantialvariation,mostPribac,1993])hasbeeninterpretedasrequiringsublithosphericofwhichisrelativelywellexplainedbyisostaticcompensationofdensitycontrasts.densitycontrastswithinthecrustandlithosphere.Forexamp

8、le,ComparisonofEarth'stopographyandbathymetryETOPO5the-?5kmexcesselevationoftheTibetanPlateauaswellasthe[U.S.DepartmentofCommerce,1992]andthenonh