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Modelling Atmospheric CO2 Vertical Profiles TRANSCOM PARIS 2005 Christopher Pickett – Heaps PhD Student (Univ. of Melbourne, AUS) Supervisor:Dr. Peter Rayner Currently studying at the LSCE
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Thank You To… Individuals Dr. Peter Rayner (Supervisor) Dr. Rachel Law (CSIRO) Dr. Philippe Ciais & others (LSCE) Organisations CSIRO Atmospheric Research LSCE, CEA University of Melbourne
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Aircraft Campaign/MissionAuthor(s) and/or Data ProvidersPeriod PROFILES Cape Grim Aerial Profile Archive GASLAB, CSIRO 1991 - 2000 Orleans Aerial Profile ArchiveLSCE, CEA1997 - Present CMDL Aerial Profile ArchivesP. Tans, CMDL/NOAA1992 - 2002 CAR, FTL, HAA, HFM, LEF, PFA, RTA, SAN TROPOSPHERIC Bible (A, B, C)Machida et al.1998, 1999, 2000 JAL (Japan/Aus)Matsueda & Inoue1993 - 2003 PEM-WEST A dc8Newell et al. 19961991 PEM-WEST B dc8Hoell et al., 19971994 PEM-TROPICS AHoell et al., 19991996 PEM-TROPICS BRaper et al., 20011999 TRACE AAndrae et al. 19961992 TRACE PJacob et al., 20032001 CARIBICBrenninkmeijer et al., 19991997 - 2001 STRATOSPHERIC ASHOEJPL, NASA1994 POLARISJPL, NASA1997 SOLVEJPL, NASA2000 STRATJPL, NASA1996 DATA PROVIDERS!!!
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Why model CO2 vertical profiles? Inversion validation Satellite Validation Potential use of profile data in atmospheric inversions
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Inversion Procedure… Use of data from 77 obs. stations Not gap filled (from GLOBALVIEW) Use of prior estimates
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Inversion Procedure… Monthly fluxes 1989 – 2002 (14 yrs) High spatial resolution:136 regions –92 land regions 44 ocean regions One yr of response f’ns from 97-98 winds 15 ‘Sampled Inversions’ removing 20 stations from the network
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Forward Model Procedure… CSIRO CCAM model Flux fields from each inversion inserted into the CCAM model Resolution200km by 18 lvls Time-step1hr Nudged by NCEP data(Inter-annual) Model operates within a Cubic-Conformal grid Advection scheme: NON LINEAR! –Semi-Lagranian horiz. advection with bi-cubic interpolation of fields –‘Non-negative constraint’ used for trace gas advection (Bermejo & Staniforth, 1992) and an ‘a posteriori conservation scheme’ is applied –Vertical advection uses a TDV scheme (Thuburn, 1993)
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Forward model procedure… Model sampled at appropriate point in time and space Produces model data directly comparable to: Surface station monthly obs. data Vertical profile data
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Model results at the surface (Examples)…
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Model results at the surface (sampled inversions)…
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Solutions to improve model fit… Iteration procedure Solve for flux estimate adjustments and adjust original CO2 flux estimates Re-run forward model with adjusted flux field
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Iteration results at the surface (examples)…
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Solutions to improve model fit… Sample inversion variability to characterise non-linearity
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Profile fit examples (CGO)
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Profile RMS Time Series (CGO) Mean RMS: 0.45ppm
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Profile Bias (mean residual) Time Series (CGO)
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What is causing errors in the model profiles? Non-Linearity Issue Profiles an instantaneous measurement Fluxes are monthly High degree of ‘scatter’ in observed profile Biomass burning events Transport
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Future plans… Analyse sampled inversion flux estimates Similar model comparison with LMDz Use of profiles to estimate carbon flux Proposed inter-comparison project Stay tuned!!!
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