Institut für Umweltphysik (IUP) Institut für Fernerkundung (IFE)

1. CarbonSat L1L2 Study Final Presentation, 3-Jul-2013 Universität Bremen, FB1 Physik und Elektrotechnik Institut für Umweltphysik (IUP) Institut für Fernerkundung (IFE) • Level 2 XCO2 and XCH4 Performance w.r.t. Clouds & Aerosols: • Nadir – from scenarios to global scale • ESA Study CarbonSat Earth Explorer 8 Candidate Mission • “Level-2 and Level-1B Requirements Consolidation Study“ • ESA Contract No4000105676/12/NL/AF M. Buchwitz, M. Reuter, J. Heymann, O. Schneising, V. Rozanov, H. Bovensmann Institute of Environmental Physics (IUP) / Institute of Remote Sensing (IFE), University of Bremen (UB), Bremen, Germany 1

2. Overview • Scatteringrelatedbiasesdue toaerosolsandundetectedcloudsincludingthin (sub-visual) cirruscloudsareexpectedtodominatetheerrorbudgetesp. w.r.t. XCO2systematicerrors (biases) • Withinthisstudythisaspecthasbeenstudied in detailusing different approaches • This presentationfocus on nadirobservationsoverland: • Simulation framework & CS instrumentparameters • Part 1: Single scenarios (short) • Part 2: Global analysis (focus) • ( Glint: seefollowingpresentationbyUoL (H. Boesch) ) 2

3. Simulation framework Estimation of random &systematic errors of CarbonSatXCO2 & XCH4 retrievals: Retrieved – true = systematic error XCO2 and XCH4 True XCO2 & XCH4 (Model) Atmosphere CO2(z), CH4(z), p(z), T(z), ... Retrieved XCO2 & XCH4 +/- random error Albedo, SZA, aerosols, clouds, ... a priori information: CO2, CH4, ... Observing System = Instrument + Retrieval Algo RTM BESD/C Various scenarios (aerosols, clouds, ...) Instrument Model Radiance Radiance @ instrument resolution & sampling, SNR, ... Specification (MRD) Instrument errors NOV-7090-SL-2551 3

4. CarbonSat Instrument Parameters From: TN-3b1 4

5. Part 1 Single scenarios (shortassufficient time neededfor Part 2; pleasesee TNs formoredetails) 5

6. Scenarios • „Main Geophysical Scenarios“: • Different SZA, waterclouds, aerosoltypes, surfacealbedos • Foreachofthem 135 „Basic Geophysical Scenarios“: • Different cirrus (opticaldepth, altitude) • AODs • VCF Details: Please see TN-3b1 6

7. Error analysisresults: Example: 135 VEG50/CA scenarios Scenario: SZA: 50o Albedo: VEGetationAerosols: OPAC Continental Average (CA) Grey: All Black: Quality filtered XCO2(FP): Precision: 0.76 +/- 0.04 ppm Bias: 0.31 +/- 1.22 ppm COD: Wellretrieved CTH: Wellretrieved AOD+WOD: Low quality(BESD/C tobeimproved) VCF: Wellretrieved From: TN-3b1 7

8. Error analysisresults (TN-3b1): Summary variousscenarios • Aerosols: CA= Continental Average, DE = DEsert • Albedo: VEG = VEGetation, SAS = Sand/soilalbedo • WOD: Optical DepthoflowlyingthinWaterclouds- not a majorissues (errorslowordetectedandflagged) • Biasescanbe large for: • DE aerosols: Improve BESD/C incl. betteruseof SWIR-2, filtering+ other (e.g., AAI filter) • Large SZA: Restrictto < 70o 8

9. Part 2 Single scenarios -> Globale scale Generation & analysisofoneyearofsimulatedCarbonSat Level 2 Activity closely linked to parallel CarbonSat LOGOFLUX study: CarbonSat L2->L4 Study LOGOFLUX ledbyNOVELTIS CarbonSat L1/L2 Requirements Study ledbyIUP, Univ. Bremen E.g. L4 applications: E.g. assessmentofcity CO2emissions (IUP: Berlin) Oneyear global analysis (errorparameterization) Single scenarios, … 9

10. Approach • Approach: • Defineorbit and generate files containing for eachground pixel information such as lat, lon, time, relevant angles (SZA, VZA, …), … • Compute for eachground pixel random and systematic XCO2 and XCH4errors and averagingkernels • CarbonSat Level 2 error (L2e) files: • A oneyeardatasetcontainingforeachsufficientlycloudfreegroundpixel all Level 2 informationasneededfor • erroranalysisof global data • inverse modellingof CO2and CH4surfacefluxes (emissionsand/oruptake) 10

11. Approach & resultsaredescribed in detail in … Buchwitz et al., AMTD, 2013 11

12. Howtogeneratethe L2e files ? MODIS: Albedo, aerosols MODIS + correction CS MRD Other: Land/seamask, surface type, topography, … C&A, albedo, … Orbit CALIPSO: Cirrus Foreachsufficientlycloudfree (MODIS) CarbonSatgroundpixel: lat, lon, time, SZA, albedo, aerosols, cirrus … Error parameterization (regression) SimulatedCarbonSat L2 observations Instrument Model RTM BESD/C CS L2e files Error parameterization scenarios Errors & a/kforeachscenario Foroneyear (2008) 12

13. „Famous“ CarbonSatspatialsampling/coveragecartoon: Berlin Germany 13

14. CarbonSat: Germany overpass: XCO2 (swath = 500 km) 2x2 km2 Swath=500km Reliableestimate Preliminary ! (dependsstrongly on retrievalalgorithm etc.) 14 Buchwitz et al., 2013

15. CarbonSat: Germany overpass: XCH4(swath = 500 km) 2x2 km2 Swath=500km Preliminary ! (dependsstrongly on retrievalalgorithm etc.) Reliableestimate 15 Buchwitz et al., 2013

16. GHG errors & relevant otherparameters 16 Buchwitz et al., 2013

17. GHG errors: FullPhysics (FP) andPRoxy (PR) 17 Buchwitz et al., 2013

18. GHG errors: Monthlyaverages (5ox5o, swath= 240 km) 18 Buchwitz et al., 2013

19. NumberofObservations per month (5ox5o, swath=240 km) Quality filterednadiroverlandonly (SZA < 70o, …) July: 46 x 106 32000 obs. per month per 5ox5o 19 Buchwitz et al., 2013

20. Regional errordistributions 20 Buchwitz et al., 2013

21. Regional errordistributions: Summary • XCO2: • Precision: ~1.2 ppm • Biases (C&A): • < 0.3 ppm: ~85% • < 0.5 ppm: ~99% • XCH4: • Precision: ~7 ppb • Biases (C&A): • < 2 ppb: ~85% • < 4 ppb: ~99% 21 Buchwitz et al., 2013

22. Summary & Conclusions Buchwitz et al., 2013 … … 22

23. Whatcanbedonewiththis ? CarbonSatdatasethasbeenusedtoanswerquestions such as: Howwellcananthropogeniccity CO2emissionsbederivedfromCarbonSat ? … andmanyotherquestions .. Interestedtoknowtheanswers ? Pleasesee Final PresentationofLOGOFLUXstudy(startsdirectly after this Final Presentation) 23