the global geodetic observing system (ggos) - its …2017/05/23 · • challenges in earth...
TRANSCRIPT
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TheGlobalGeodeticObservingSystem(GGOS)-itsRoleanditsActivities
MeetingattheGeospatialInformationAuthorityofJapan(GSI)May23,2017
MichaelPearlman1,HaraldSchuh2,Detlef Angermann 3
andCareyNoll4
1Centerfor Astrophysics,CambridgeUSA2GeoForschungsZentrum,PotsdamGermany
3Technische Universität München,MunichGermany4NASAGoddardSpaceFlightCenter,GreenbeltUSA
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JapaneseInstitutionshavebeenInvolvedinInternationalSpaceGeodesyPograms since
earlyintheSpaceProgram
EarlySLRSystematTokyoAstronomicalObservatory
Prof.Yoshihide Kozai
InternationalAssociationofGeodesy(IAG)CentralObjectiveGeodeticObservationofEarthProcesses
Processesintheatmosphereandhydrosphere:watercycle
pointpositioning
ProcessesinthesolidEarth:geodynamics(deformation)
surfacescanning gravitymeasurementSRTM(InSAR)
andthegravityfieldvariationsoftherotationdeformations
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FundamentalRequirementforMonitoringGlobalChange
Thestudy,understandingandmodellingoftheeffectsofglobalchangerequire:• precise,consistent andstablereferenceframes,• standardsandmodelsforthethreegeodeticparametergroups:
• Earthgeometryandkinematics,• Earthgravityfieldanddynamics,• Earthorientationandrotation.
Thereferenceframeisthebasisuponwhichwemeasurechangeoverspace,time,andevolvingtechnology.Itmustfulfill thefollowingconditions:• Oneordermoreprecisethanthemagnitudeofthephenomenatobeanalysed;
• Globallyconsistentandreliable(highprecisionatanyplaceoftheEarth’ssurface);
• Stableoverlongperiods(highprecisionatanytime).
GlobalGeodeticObservingSystem(GGOS)
• Established by the IAG in 2004 to be its Observing System
• Vision: Advancing our understanding of the dynamic Earth system by quantifying our planet’s changes in space and time to:
– Advance Earth Science (Earth, oceans, ice, atmosphere, etc)
– Help us better understand the processes
– Help us make intelligent societal decisions
• Mode of Operation: Works with the IAG components (IGS, ILRS, IVS, IDS, IGFS, IERS, IAG commissions, etc.) to provide the geodetic infrastructure necessary for monitoring the Earth System and Global Change:
– observations needed to monitor, map, and understand changes in the Earth’s shape, rotation, and mass distribution;
– the TERRESTRIAL REFERENCE FRAME and CELESTIAL REFERENCE FRAME for measuring and consistently interpreting key global change processes;
– Other data products that require integration among measuring techniques: Unified height systems, Unified sea level model, Natural hazard warning tools, etc
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Approaches of GGOS
▪ Combination and integration of all available observations, methods, ...▪ Combine physical measurements and geometric techniques▪ Improve our understanding of the interactions in ”System Earth“
GeodesyisanessentialinputtoseveraloftheareasoffocusoftheGlobalEarthObservationSystemofSystems(GEOSS)
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GGOSshouldbenefitscienceandsocietybyprovidingthefoundationsuponwhichadvancesinEarthscienceandapplicationsarebuilt.
GGOSFIELDSFORSCIENCEANDSOCIETYINGENERAL
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IAGBylaws1(d)
“TheGlobalGeodeticObservingSystemworkswiththeIAGcomponentstoprovidethegeodeticinfrastructurenecessaryformonitoringtheEarthsystemandglobalchangeresearch.”
ThevisionofGGOSis
“AdvancingourunderstandingofthedynamicEarthsystembyquantifying ourplanet’schangesinspaceandtime.”
GGOS today
PracticalApplicationsofSpaceGeodesyUSNationalResearchCouncilStudy
• Geodesy isthescienceoftheEarth’sshape,gravityandrotation,includingtheirevolutionintime.
• Techniques usedtoobservethegeodeticpropertiesoftheEarthprovidethebasisfortheInternationalTerrestrialReferenceFrame(ITRF)
• TheITRF isthefoundationforvirtuallyallairborne,space-based,andground-basedEarthobservations,andisfundamentallyimportantforinterplanetaryspacecrafttrackingandnavigation.
TheITRFperformancerequirementforsealevelmeasurementis1mmreferenceframeaccuracyand0.1mm/yearstability(NRC2010).
MoststringentrequirementonITRFperformanceissealevel
ProvidedthroughthecourtesyofProf.BernardMinster
GLOBALReferenceFrame(TerrestrialandCelestial)
• Basis on which we measure changes over time, space, and evolving technology• Most stringent requirement from sea level rise, but other applications are close behind
– “accuracy of 1 mm, and stability at 0.1 mm/yr” (a factor of 5 - 10 improvement)• Accessibility: 24 hours/day; worldwide
– Users anywhere on Earth can position their measurements in the reference frame• Space Segment:
– LAGEOS, LARES, Etalon, GNSS, DORIS to define the reference frame• Ground Segment (Core and Co-located ground sites):
– Global distributed network of “modern technology”, co-located SLR, VLBI, GNSS, DORIS stations locally tied together with accurate site ties
– Dense GNSS ground station network to distribute the frame globally to the users• Reference Frame Formulation provided by the IERS from data provided by the IAG
Services: IGS, IVS, ILRS, and IDS
VLBI SLR GNSS DORIS VectorTie
WhatdoeseachtechniqueprovidetotheReferenceFrame?
• SLR:UniquelyprovidesEarthCenterofMass;• VLBI:ProvidesEOPparametersandtheconnectionwiththe
CelestialReferenceFrame;• SLRandVLBIindependentlyprovideScale• GPS:Globalcoverageanddensity• DORIS:Globalcoverage• Gravimetry:Helpinterpretstationdynamics
• Co-locatedSLR,VLBI,GNSSandDORIS(whereavailable)sothattheirmeasurementscanberelatedtosub-mmaccuracy
• Whydoweneedmultipletechniques?– Eachtechniquemakesitsmeasurementsinadifferentwayand
thereforeeachmeasuressomethingalittledifferent:• Terrestrial(satellite)versescelestial(quasar)reference• Rangeversesrangedifferencemeasurements• Broadcastupversesbroadcastdown• Radioversesoptical• Activeversespassive• Geographiccoverage
Why Multiple Techniques at a Site?
SLR
VLBI
GNSS
DORIS
EarlySimulationStudiestoScopetheNetwork(impactontheReferenceFrame)
(ErricosPavlis)
Earlysimulationstudiesshowedtheweneeded:• ~32globallydistributed,wellpositioned,newtechnology,co-locationsiteswill
berequiredtodefineandmaintainthereferenceframe;• ~16oftheseco-locationstationsmusttrackGNSSsatelliteswithSLRto
calibratetheGNSSorbitswhichareusedtodistributethereferenceframe.
• DesignInitiative,butitamajorChallenge• Willrequiretime,significantresources,andstronginternationalparticipation• Nowwerecognizethatitwillbeacombinationofcoreandcolocationsiteswith
applegeographicdistribution.
GGOS 2020 Book (2009)
Content: main arguments for GGOS
• Goals, achievements and tools ofmodern geodesy
• Earth science requirements forgeodesy
• Maintaining a modern society (9 societal benefit areas)
• Future geodetic reference frames• Future Global Geodetic Observing
System (GGOS)• GGOS 2020
GGOS: Meeting the Requirements of a Global Society on a Changing Planet in 2020. Eds. H.-P. Plag and M. Pearlman. Springer 2009. p. 332
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GGOS (Chair:Hansjörg Kutterer,Germany)
StructureoftheGlobalGeodeticObservingSystem
IAGServ icesIAGCommissions
StationsParticipatingintheGGOSAffiliatedNetwork
(CallforParticipation)
PresentandProjectedCORENetwork(all4techniques)
Remark:GlobalgeodeticnetworkdoesnotalwaysmeetGGOSrequirements
• Combinationofnewandlegacyequipment
• Unequalnetworkdistribution
• Localtiesoftechniques
• Stillsystematicobservationalerrors
• Needfor~10timesimprovementinmeasurementaccuracy
GGOS Site Requirements Document(http://cddis.gsfc.nasa.gov/docs/GGOS_SiteReqDoc.pdf)
• Introduction and Justification – What is a Fundamental Station?– Why do we need the Reference Frame?– Why do we need a global network?– What is the current situation?– What do we need?
• Site Conditions– Global consideration for the location– Geology– Site area– Weather and sky conditions– Radio frequency and optical Interference– Horizon conditions– Air traffic and aircraft Protection– Communications– Land ownership– Local ground geodetic networks– Site Accessibility– Local infrastructure and accmmodations– Electric power– Site security and safety– Local commitment
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FirstgeospatialresolutionadoptedbyUNGeneralAssembly
First Geospatial UN Resolution
• GlobalGeodeticReferenceFrame(ITRFandICRFcombination)forSustainableDevelopment(GGRF)resolution- No.A/69/L.53-
• adoptedbytheUnitedNationsGeneralAssemblyon26th ofFeb,2015
• co-sponsoredby52MemberStatesincludingJapan
• …first resolution recognizing theimportance of aglobally coordinatedapproach togeodesy– thediscipline focused onaccurately measuring theshape,rotation andgravitational field of planetEarth.
• TheGeneralAssembly resolution,AGlobalGeodeticReferenceFrameforSustainableDevelopment,outlines thevalue of ground-based obserationsandremotesatellite sensing when tracking changes inpopulations,icecaps,oceans andtheatmosphere over time.
Japanesesubmissiontothe GGOSCallforParticipation- SubmittedbyDr SMatsuzaka(JapaneseGGOSWGChairatthattime)
andapprovedbyGGOSBureauin2014
Tsukuba(VLBI+GNSS+Gravimeter)Ishioka(VLBI+GNSS)Aira (VLBI+GNSS)Chichijima (VLBI+GNSS+Gravimeter)Shintotsukawa (VLBI+GNSS+Gravimeter)Tanegashima(SLR+GNSS)Simosato(SLR+GNSS)Mizusawa (VLBI+GNSS+Gravimeter)Koganei(SLR+VLBI+GNSS)Kashima(VLBI+GNSS)Syowa(VLBI+DORIS+Gravimeter)
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• ChallengesinEarthobservation:
– verysmall but significant trendsneedtobemonitored(platetectonics,sealevelchange,globalisostaticadjustment(GIA),climatechange,…)
– veryfastevents(earthquakes,tsunami,landslides,…)
• Geodesyis afundamentaltool for exploration andunderstandingofour planet
• GlobalGeodeticObservingSystem(GGOS)isthe geodeticcontributiontoEarthobservation(within GEOSS,the GlobalEarthObserving Systemof Systemsunder GEO,the GrouponEarthObservations)
• GGOSprovidesthemetrologicalbasis (interms of reference frames,timeandfrequencytransfer)for amultitude of other Earthobservations
• ChallengesinEarthobservationrequirealotofgeodeticexpertise
• PrecisedataandmonitoringbygeodesyisneededformanyotherEarthsciences
• Alot of new developments (technology,e.g.application of quantum physics for geodeticmeasurements,new extremely precise clocks,next space missions,micro satellites fürgeodesyetc.)offer many new tasks (andalsojobs)
Conclusions
Summary
• Challengingprogramwithveryimportantscienceandsocietalbenefits
• Technologiesarematuring• Globaldistributionisessential;successneedstheenhancednetworksthatwilldependonpartnerships
• Verylargeopportunityforparticipationinanalysisandscientificresearch
• Needtoengageyoungscientistsandstudents
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FundamentalRequirementforMonitoringGlobalChange
Thestudy,understandingandmodellingoftheeffectsofglobalchangerequireprecise,consistent andstablereferenceframes,standardsandmodelsforthethreegeodeticparametergroups:Earthgeometryandkinematics,Earthgravityfieldanddynamics,Earthorientationandrotation. Thereferenceframeisthebasisupon
whichwemeasurechangeoverspace,time,andevolvingtechnology.Itmustfulfill thefollowingconditions:• Oneordermoreprecisethanthemagnitudeofthephenomenatobeanalysed;
• Globallyconsistentandreliable(highprecisionatanyplaceoftheEarth’ssurface);
• Stableoverlongperiods(highprecisionatanytime).