Title. GOSAT CO 2 Inversion Inter-comparison Experiment Phase-2: interim progress report

Transcription

1 Title IWGGMS-14 May 9, 2018 GOSAT CO 2 Inversion Inter-comparison Experiment Phase-2: interim progress report H. Takagi 1, S. Houweling 2, S. Maksyutov 1, D. Baker 3, F. Chevallier 4, F. Deng 5, L. Feng 6, F. Jiang 7, and participating modelers 1 National Institute for Environmental Studies, Japan 2 Vrije Universiteit Amsterdam, Netherland 3 Cooperative Institute for Research in the Atmosphere, Colorado State University, USA 4 Laboratoire des Sciences du Climat et de l Environnement, France 5 Department of Physics, University of Toronto, Canada 6 School of Geosciences, University of Edinburgh, UK 7 International Institute for Earth System Science, Nanjing University, China

2 Introduction Title 1 Surface-based CO 2 observations y Inverse modeling system y = h z Satellite X CO2 retrievals ( ) + ε y Global carbon flux estimates z To gain further the process-level understanding of carbon fluxes being modified by human activities, it is essential to quantify, evaluate, and reduce uncertainties in the flux estimation process Model inter-comparisons provide such an

3 GOSAT TitleCO 2 Inversion Inter-comparison studies 2 GOSAT inversion intercomparison Phase-1 (finished) Free-style inversion experiment Input data Inversion systems Inversion results Houweling et al JGR GOSAT X CO2 ACOS, NIES, RemoTec, PPDF-S, U.Leicester Surface CO 2 NOAA, WDCGG, Site selection, Data number Prior fluxes CASA, ORCHIDEE, VISIT, Takahashi, CDIAC, ODIAC Free to choose from System A System B System C System D System E Largest possible spread in satellite-based flux estimates was evaluated. Period: 12 mon. ( 09-10) GOSAT inversion intercomparison Phase-2 (this study, ongoing) Input data Common Input data: - GOSAT X CO2 - Surface CO 2 - Prior fluxes Common-input inversion experiment Inversion systems System A System B System C System D System E Inversion results We evaluate uncertainty contribution of 1. inversion system differences (robustness of satellitebased flux estimates) 2. input data differences (by comparing to Phase-1) Period: 57 mon. ( 09-14)

4 Phase-2 Title Experimental protocol 3 Common input dataset: CO 2 concentration and a priori flux ACOS B3.5 LITE X CO2 retrieval dataset use good quality, bias-corrected X CO2 use both land and ocean retrievals NOAA ObsPack GV plus surface observations 44 sites out of 205 were selected for their fewer data gaps over period NOAA CarbonTracker 2015 a priori flux data CASA-GFED 4.1s, OIF ocean, ODIAC fossil fuel, and GFED 4.1s fire (downscaled to CT specifications) 3-hourly fluxes on a 1º 1º mesh used (Courtesy of A. Jacobson, NOAA and source data providers)

5 Phase-2 Title Experimental protocol 4 Inversion systems and variance-covariance matrices Inversion system: use best system setups by each participant Variance-covariance matrices Variance-covariance matrices for observation (R) and prior flux uncertainties (B) were defined by each participant. But to maintain weight of CO 2 obs. within a comparable range among the participants, minimum values for the diagonals of matrix R are set to: ACOS B3.5 X CO2 : 2.0 ppm ObsPack GVplus surface CO 2 : 0.5 ppm To avoid over-constraining prior fluxes, participants are asked to adjust balance between R and B (prior flux unc.) such that posterior reduced Χ 2 has an upper bound of 1. Flux data submitted: Surface-data-only, Satellite-data-only, and Sfc. & Sat. combined

6 Participating Title groups and modeling systems 5 Participants Phase-2 This report Participants Phase-1 (finished) Inversion Method Atmospheric Transport Model Model resolution CSU-NOAA CSU-NOAA Variational PCTM lev LSCE LSCE Variational LMDZ lev NIES NIES Kalman Smoother NIES lev SRON SRON Variational TM5-4DVAR lev U.Edinburgh U.Edinburgh Ens. Kalman Filter GEOS-Chem lev U.Toronto U.Toronto Variational GEOS-Chem lev Nanjing U. - Ens. Kalman Filter MOZART v lev MPI-BGC Variational TM lev CAO Kalman Smoother GELCA v lev

7 Results: TitleGlobal total flux 6 Flux (GtC/yr net) Flux (GtC/yr net) Global Land Global Ocean : CSU : LSCE : NIES : SRON CSU LSCE NIES SRON UOE UTRO NJU NOAA growth rate* : U. Toronto : Nanjing U. : U. Edinburgh : A priori Surface & Satellite combined inversion result Global Annual Total (GtC/yr net) * Source: ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_gr_gl.txt (updated on )

8 Title 57-mon. flux time series for TransCom land regions (Jun Feb. 2014) : CSU : LSCE : NIES : SRON : U. Toronto : Nanjing U. : U. Edinburgh : A priori Satellitedata-only inversion Jun 09 Feb 14 7 GtC / Region / Year

9 57-mon. Title flux time series for TransCom land regions 8 : Phase-1 : Phase-2 Satellite only inversion & Phase-1 results overlaid (NJU not included) Jun 09 Feb 14 GtC / Region / Year

10 57-mon. Title flux time series for TransCom land regions 9 : Phase-1 mean : Phase-1 ±2σ : Phase-2 mean : Phase-2 ±2σ Satellite only inversion & Phase-1 results overlaid (NJU not included) Jun 09 Feb 14 GtC / Region / Year

11 Changes Title in spread of flux estimates (Phase 1 2) Spread (1σ) of six flux estimates (annual flux Jun 09-May 10) (Nanjing U. not included) 10 Region Unit: GtC / yr Satellite-only estimate Phase-2 Phase-1 Boreal N America TransCom Regions Temp. N America Trop. America S. America Values in red : between-model uncertainty indicates degree to which inv. system differences contribute to range of satellite-based flux estimates for period. Trop. Africa S. Africa Boreal Eurasia Temp. Asia Trop. Asia Australia Europe Average reduction (Phase 1 2) 35% (Range: 0 60%)

12 Changes Title in spread of flux estimates 11 update update update update update GtC / Region / Year (net) GOSAT inversion intercomparison Phase 0 (finished) GOSAT X CO2 data products NIES L2 v02.** NIES L2 v02.21 ACOS B2.1 ACOS B3.5 PPDF-S PPDF-S v02.21 RemoTeC v2.0 RemoTeC v2.3.8 U. Leicester v3g U. Leicester v7.0 : Phase-2 (this study) : Phase-1 : Phase-0 (above ) : Phase-0 update Inversion system NIES system Inversion results Takagi et al GRL Impact of differences in X CO2 products on fluxes was evaluated. ( yr. period same as Phase-1) Annual mean fluxes and 1σ spread over 11 land regions (1yr ) 11 TransCom land regions Satellite only inversion Net flux Phase-2 spread is comparable to Phase-0 spread (X CO2 differences).

13 Changes Title in spread of reginal flux estimates (Phase-0) 12 GOSAT X CO2 retrievals NIES L2 v02.** ACOS B2.1 PPDF-S RemoTeC v2.0 U. Leicester v3g 2018 update NIES L2 v02.21 ACOS B3.5 PPDF-S v02.21 RemoTeC v2.3.8 U. Leicester v7.0 Spread (1σ) of five flux estimates ( yr.) Region Satellite-only estimate Phase update Phase-0 ( data) Boreal N America Temp. N America Trop. America S. America Trop. Africa S. Africa Boreal Eurasia Temp. Asia Trop. Asia Australia Europe Average reduction (Phase 0 0 update) 22%

14 Tropics Titlesink minus NH Extra Tropics sink 13 Comparison in Houweling et al JGR NH Ext. Trop. Regions : 1, 2, 7, 8, & 11 Tropical regions : 3, 5, 9 Flux = (Tropics sink NH Extra Tropics sink) Positive Flux NH Ext. Trop. sink is stronger than Tropics sink Phase-1 (Figure 5 Houweling et al JGR) Phase-2 Flux Satellite data only Use of sat. data leads to large sink in NH?! Flux Surface data only inversion GtC/yr Was the Phase-1 scatter related to Phase-1 s - a priori data differences? - X CO2 data differences? - variance setting diff.? - combination of all? etc.?

15 Title Influence of different a priori flux data used in inversion (Jun May 2010) : CSU a priori : LSCE a priori Phase-1 : NIES a priori a priori data : SRON a priori : U. Toronto a priori : U. Edinburgh a priori : CT2015 a priori 14 Jun 09 May 10 GtC / Region / Year

16 Title Influence of different a priori flux data used in inversion (Jun May 2010) 15 ACOS B3.5 (Single X CO2 data) NIES system CT2015 Prior NIES Prior (Two individual a priori data) Jun 09 May 10 GtC / Region / Year

17 Influence Title of different a priori flux data used in inversion 16 Annual mean regional fluxes and 1σ spread (Jun May 2010) GtC / Region / Year (net) Satellite only inversion Net flux : Phase-2 (this study) : Phase-1 : Phase-0 : Phase-0 update : Phase-1 a priori

18 Mean Title of seven Phase-2 fluxes on a 1x1 grid (annual) 17 Surface & satellite combined inversion (fossil emissions not included) Sink Source (gc / m 2 / day) Amazonia (GtC/region/yr) : A priori : Surface only : Satellite only : Combined Australia (GtC/region/yr) (no fossil emissions) (no fossil emissions) : A priori : Surface only : Satellite only : Combined The seven models agree on - Australia went thorough a sink-to-neutral transition (Detmers et al. 2015) - and Amazonia in the opposite (a see-saw oscillation)

19 SD Title of seven Phase-2 fluxes on a 1x1 grid (annual) ➀ Surface-data-only inversion 18 ➁ Surface & satellite combined inversion Difference (➁ - ➀) Standard deviation (gc / m 2 / day) Less spread than ➀ More spread than ➀ (gc / m 2 / day) Larger spreads are found in tropical regions (Central Africa, Amazonia, and SE Asia). Use of satellite data causes larger spread among the seven spread may be related to transport differences for column CO 2 data.

20 Concluding Title remarks and future work 19 Interim report on GOSAT CO 2 inversion inter-comparison Phase-2: Results by 7 inversion systems are compared, and uncertainty contribution of model system differences is evaluated. Phase-2 spread is less than that of Phase-1 by 35% on average ( input data contribution may not be negligible) Phase-2 spread is comparable to that of Phase-0. σ(inv. system differences) σ(x CO2 retrieval differences) Phase-0 update shows a reduction in the influence by X CO2 product differences (by ~30%). Signs of agreement were seen in responses to ENSO-related weather anomalies (Australian record drought/flooding ). Upcoming: Inversion evaluation with CO 2 observation data Analysis of concentration data More flux/uncertainty IAV analysis & comparison to prev. studies

21 Supplemental Title slides follow S

22 Title 57-mon. flux time series for TransCom land regions (Jun Feb. 2014) : CSU : LSCE : NIES : SRON : U. Toronto : Nanjing U. : U. Edinburgh : A priori Surface data inversion Jun 09 Feb 14 8 GtC / Region / Year

23 Title 57-mon. flux time series for TransCom land regions (Jun Feb. 2014) : CSU : LSCE : NIES : SRON : U. Toronto : Nanjing U. : U. Edinburgh : A priori Surface & Satellite combined data inversion Jun 09 Feb 14 7 GtC / Region / Year

24 GtC / Region / Year Mean Title of seven Phase-2 fluxes over : A priori : Surface only : Satellite only : Combined Fossil emission not included

25 GtC / Region / Year Mean Title of seven Phase-2 fluxes over (ocean) 17 : A priori : Surface only : Satellite only : Combined Fossil emission not included

26 Mean Title of seven Phase-2 fluxes: Europe and N. Africa Phase-2 Multi-year Phase-1 (1yr: Jun 09 - May 10) (Houwellinget al., 2015 JGR) Phase-1 (Figure 5 H2015 JGR) 18 GtC / Region / Year Flask GOSAT Europe : A priori : Surface only : Satellite only : Combined Red values: no weighting applied Flask - GOSAT difference was found to be large in Phase-1 ( 1GtC/yr) Satellite-only Flux (Tropics NH Extra Tropics) Phase-2 (Jun 09 - May 10) Flask GOSAT Northern Africa Surface-only Flux (Tropics NH Extra Tropics) Was the Phase-1 shift related to Phase-1 - a priori data differences? - X CO2 data differences? - variance setting diff.? - combination of all? etc.?