ECCO-Sea Level: The next phase in the “Estimating the Circulation … · 2017. 12. 13. · Mean...
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Figure 1: Model grid (LLC90) ECCO-Sea Level: The next phase in the “Estimating the Circulation and Climate of the Ocean” Project Ichiro Fukumori 1 , Patrick Heimbach 2 , Chris Hill 3 , Dimitris Menemenlis 1 , Rui M. Ponte 4 1 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA, 2 University of Texas, Austin, TX USA, 3 Massachusetts Institute of Technology, Cambridge, MA USA, 4 Atmospheric and Environmental Research, Lexington, MA USA Characteristics ECCO Version 4 Release 3 model MITgcm grid system latitude-longitude-cap resolution 0.3˚~1˚, 50 levels sea-ice model prognostic external forcing bulk parameterization, geothermal heating period 1992-2015 correlation separate mean from anomaly Variable Observations Sea level TOPEX/Poseidon (1993-2005), Jason-1&2 (2002-2015), CryoSat -2 (2011-2015), SARAL/AltiKa (2013-2015) Temperature profiles Argo floats (1995-2015), XBTs (1992-2008), CTDs (1992-2011) Salinity profiles Argo floats (1997-2015), CTDs (1992-2011), SEaOS (2004-2010) Sea surface temperature AVHRR (1992-2013), AMSR-E (2002-2010) Sea surface salinity Aquarius (2011-2013) Sea-ice concentration SSM/I DMSP-F11, 13, & 17 (1992-2015) Ocean bottom pressure GRACE (2002-2014) Mean dynamic topography DTU13 (1992-2012) Table 2: Characteristics of ECCO Version 4 Release 3 (Fukumori et al., 2017) Table 1: Data employed in the latest ECCO estimate (Version 4 Release 3). (New items in red.) References: 1.Fukumori, I., et al. (2015), Prog Oceanogr, 134, 152-172, doi:10.1016/j.pocean.2015.01.013. 2.Fukumori, I., et al. (2017), ftp://ecco.jpl.nasa.gov/Version4/Release3/doc/v4r3_summary.pdf 3.Piecuch, C. G. (2017), J. Geophys. Res., 122(9), 7181-7197, doi:10.1002/2017JC012845. 4.Roemmich, D., and J. Gilson (2009), Prog Oceanogr, 82, 81-100, doi:10.1016/j.pocean.2009.03.004. 5.Schodlok, M. P., et al. (2016), J. Geophys. Res., 121(2), 1085-1109, doi:10.1002/2015JC011117 Acknowledgement: This study was conducted in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2017. All rights reserved Figure 2: Global mean sea level change ECCO Altimetry Figure 5: Subpolar North Atlantic heat content change: (A) ECCO-data comparison, (B) ECCO budget. (Piecuch et al., 2017) data variance Roemmich & Gilson (2009) ECCO Figure 3: Differences with data (temperature). ECCO (red) has more uniform values across different data sets than does gridded Argo (black). Significantly, ECCO values are slightly smaller than gridded Argo for most except Argo data themselves. Figure 4: Global mean salinity change: (A) Argo, (B) ECCO Note absence of seasonal cycle and trend in (A). (A) (B) Figure 6: Coherent variation of Arctic ocean bottom pressure: (A) Explained variance by variation at North Pole, (B) Explained variance by wind at different locations, (C) Sensitivity to along-bathymetry wind. (Fukumori et al., 2015) Figure 7: Mean basal melt rate (m/y) for Filchner Ronne Ice Shelf: (A) observations, (B) MITgcm. (Schodlok et al., 2016) The ocean state estimates of the “Estimating the Circulation and Climate of the Ocean” (ECCO) Consortium (http://www.ecco-group.org/) combines nearly all extant observations of the ocean (Table 1) with a state-of- the-art ocean general circulation model spanning the globe (Figure 1, Table 2) by adjusting its atmospheric forcing and other independent controls to minimize model-data discrepancies using the adjoint method. The estimate provides a description of the ocean consistent with observations ( Figures 2, 3, 4) and dynamical and kinematical first principles. For instance, property budgets can be closed in terms of explicit processes, making amenable investigations of attribution and causation of the oceanic state (Figures 5, 6). Efforts are underway to further advance the ECCO estimate to study Earth’s climate with a focus on improving understanding and prediction of global and regional sea level change. The new initiative will incorporate capabilities for coupled ocean and ice sheet estimation (Figure 7) with model resolution refined to eddy-permitting scales (1/3°& 1/6 °). Simultaneously, the scope and usability of the estimate will be expanded in support of the broader climate science community, for instance, by an open source adjoint of the ocean model. Heat budget can be analyzed by evaluating its contributing elements (Figure 5); The model adjoint provides an effective means to examine attribution and causation (Figure 6); ( ) F t q q q q ¶ = -Ñ× + Ñ× + ¶ u D 0 p t V c dVdt r ´ òòòò () () ( ) ( ) , , df f D ¶ » -D ¶ -D ååå i i t i Jt Jt t t t t x x x (A) (B) (A) (B)
Transcript of ECCO-Sea Level: The next phase in the “Estimating the Circulation … · 2017. 12. 13. · Mean...
Figure1:Modelgrid(LLC90)
ECCO-SeaLevel:Thenextphaseinthe“EstimatingtheCirculationandClimateoftheOcean”Project
IchiroFukumori1,PatrickHeimbach2,ChrisHill3,DimitrisMenemenlis1,RuiM.Ponte41JetPropulsionLaboratory,CaliforniaInstituteofTechnology,Pasadena,CAUSA,2UniversityofTexas,Austin,TXUSA,
3MassachusettsInstituteofTechnology,Cambridge,MAUSA,4AtmosphericandEnvironmentalResearch,Lexington,MAUSA
Characteristics ECCOVersion4Release3model MITgcm
gridsystem latitude-longitude-capresolution 0.3˚~1˚,50levels
sea-icemodel prognostic
externalforcing bulkparameterization,geothermalheating
period 1992-2015correlation separatemeanfromanomaly
Variable ObservationsSealevel TOPEX/Poseidon(1993-2005),Jason-1&2(2002-2015),
CryoSat-2(2011-2015),SARAL/AltiKa (2013-2015)Temperatureprofiles Argofloats(1995-2015),XBTs(1992-2008),CTDs(1992-2011)Salinityprofiles Argofloats(1997-2015),CTDs(1992-2011),SEaOS (2004-2010)Seasurfacetemperature AVHRR(1992-2013),AMSR-E(2002-2010)Seasurfacesalinity Aquarius(2011-2013)Sea-iceconcentration SSM/IDMSP-F11, 13,&17(1992-2015)Oceanbottompressure GRACE(2002-2014)Meandynamictopography DTU13 (1992-2012)
Table2:CharacteristicsofECCOVersion4Release3(Fukumorietal.,2017)Table1:DataemployedinthelatestECCOestimate(Version4Release3).(Newitemsinred.)
References:1.Fukumori,I.,etal.(2015),Prog Oceanogr,134,152-172,doi:10.1016/j.pocean.2015.01.013.2.Fukumori,I.,etal.(2017),ftp://ecco.jpl.nasa.gov/Version4/Release3/doc/v4r3_summary.pdf3.Piecuch,C.G.(2017),J.Geophys.Res.,122(9),7181-7197,doi:10.1002/2017JC012845.4.Roemmich,D.,andJ.Gilson(2009),Prog Oceanogr,82,81-100,doi:10.1016/j.pocean.2009.03.004.5.Schodlok,M.P.,etal.(2016),J.Geophys.Res.,121(2),1085-1109,doi:10.1002/2015JC011117
Acknowledgement:ThisstudywasconductedinpartattheJetPropulsionLaboratory,CaliforniaInstituteofTechnology,underacontractwiththeNationalAeronauticsandSpaceAdministration.©2017.Allrightsreserved
Figure2:Globalmeansealevelchange
ECCO
Altimetry
Figure5:SubpolarNorthAtlanticheatcontentchange:(A)ECCO-datacomparison,(B)ECCObudget.(Piecuchetal.,2017)
data variance
Roemmich & Gilson (2009)
ECCO
Figure3:Differenceswithdata(temperature).ECCO(red)hasmoreuniformvaluesacrossdifferentdatasetsthandoesgriddedArgo(black).Significantly,ECCOvaluesareslightlysmallerthangriddedArgoformostexceptArgo
datathemselves.Figure4:Globalmeansalinitychange:(A)Argo,(B)ECCO
Noteabsenceofseasonalcycleandtrendin(A).
(A)
(B)
Figure6:CoherentvariationofArcticoceanbottompressure:(A)ExplainedvariancebyvariationatNorthPole,(B)Explainedvariancebywindatdifferentlocations,(C) Sensitivitytoalong-bathymetrywind.(Fukumorietal.,2015)
Figure7:Meanbasalmeltrate(m/y)forFilchnerRonneIceShelf:(A)observations,(B)MITgcm.(Schodlok etal.,2016)
Theoceanstateestimatesofthe“EstimatingtheCirculationandClimateoftheOcean”(ECCO)Consortium(http://www.ecco-group.org/)combinesnearlyallextantobservationsoftheocean(Table1)withastate-of-the-artoceangeneralcirculationmodelspanningtheglobe(Figure1,Table2)byadjustingitsatmosphericforcingandotherindependentcontrolstominimizemodel-datadiscrepanciesusingtheadjointmethod.Theestimateprovidesadescriptionoftheoceanconsistentwithobservations(Figures2,3,4)anddynamicalandkinematicalfirstprinciples.Forinstance,propertybudgetscanbeclosedintermsofexplicitprocesses,makingamenableinvestigationsofattributionandcausationoftheoceanicstate(Figures5,6).
EffortsareunderwaytofurtheradvancetheECCOestimatetostudyEarth’sclimatewithafocusonimprovingunderstandingandpredictionofglobalandregionalsealevelchange.Thenewinitiativewillincorporatecapabilitiesforcoupledoceanandicesheetestimation(Figure7)withmodelresolutionrefinedtoeddy-permittingscales(1/3°&1/6°).Simultaneously,thescopeandusabilityoftheestimatewillbeexpandedinsupportofthebroaderclimatesciencecommunity,forinstance,byanopensourceadjointoftheoceanmodel.
Heatbudgetcanbeanalyzedbyevaluatingitscontributingelements(Figure5);
Themodeladjointprovidesaneffectivemeanstoexamineattributionandcausation(Figure6);
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