简介：TheuniquegeographicallocationandhighaltitudeoftheTibetanPlateaucangreatlyinfluenceregionalweatherandclimate.Inparticular,theAsiansummermonsoon(ASM)anticyclonecirculationsystemovertheTibetanPlateauisrecognizedtobeasignificanttransportpathwayforwatervaporandpollutantstoenterthestratosphere.Toimproveunderstandingofthesephysicalprocesses,amulti-locationjointatmosphericexperimentwasperformedovertheTibetanPlateaufromlateJulytoAugustin2018,fundedbythefiveyear(2018–2022)STEAM(stratosphereandtroposphereexchangeexperimentduringASM)project,duringwhichmultipleplatforms/instruments—includinglong-durationstratosphericballoons,dropsondes,unmannedaerialvehicles,specialsoundingsystems,andground-basedandsatellite-borneinstruments—willbedeployed.Thesecomplementarymethodsofdataacquisitionareexpectedtoprovidecomprehensiveatmosphericparameters(aerosol,ozone,watervapor,CO2,CH4,CO,temperature,pressure,turbulence,radiation,lightningandwind);therichnessofthisapproachisexpectedtoadvanceourcomprehensionofkeymechanismsassociatedwiththermal,dynamical,radiative,andchemicaltransportsovertheTibetanPlateauduringASMactivity.

简介：

简介：Weanalyzed360permanentandcampaignGPSdatafrom1999to2017inthesouthernSichuan-Yunanblock,andobtainedcrustalhorizontaldeformationinthisregion.Then,wederivedthestrainrateusingamulti-scalesphericalwaveletmethod.ResultsrevealacomplexpatternoftectonicmovementinthesouthernSichuan-Yunnanblock.ComparedtothestableEurasianplate,themaximumrateofthehorizontaldeformationinthesouthernSichuan-Yunnanblockisapproximately22mm/a.TheXiaojiangfaultshowsasignificantlylowerdeformation—aleft-lateralstrike-slipmovementof9.5mm/a.TheHonghefaultclearlyshowsacomplexsegmentaldeformationfromthenorthtosouth.ThenorthernHonghefaultshows4.3mm/arightstrike-slipwith6.7mm/aextension;thesouthernHonghefaultshows1.9mm/arightstrike-slipwith1.9mm/aextension;thejunctionzoneintheHongheandLijiang–Xiaojinhefaultsshowsanobviousclockwise-rotationdeformation.Thestraincalculationresultsrevealthatthemaximumshear-strainrateinthisregionreaches70nstrain/a,concentratedaroundtheXiaojiangfaultandatthejunctionoftheHongheandLijiang–Xiaojinhefaults.Wenotethatmostoftheearthquakeswithmagnitudesof4andabovethatoccurredinthisregionwerewithinthehighshearstrain-ratezonesandthestrainrategradientboundaryzone,whichindicatesthatthemagnitudeofstrainaccumulationiscloselyrelatedtotheseismicactivities.Comparisonofthefastshear-wavepolarizationdirectionoftheupper-crustwiththeupper-mantleanisotropyandthedirectionofthesurfaceprincipalcompressivestrainrateobtainedfromtheinversionoftheGPSdatarevealsthatthedirectionofthesurfaceprincipalcompressivestrainisbasicallyconsistentwiththefastshear-wavepolarizationdirectionoftheuppercrustanisotropy,butdifferentfromthepolarizationdirectionoftheuppermantle.OurresultssupportthehypothesisthattheprincipalelementsofthedeformationmechanisminthesouthernSichuan-Yunnanblockaredeco