1. An attempt to quantify fossil fuel CO 2 over Europe Ute Karstens 1, Ingeborg Levin 2 1 Max-Planck-Institut für Biogeochemie, Jena 2 Institut für Umweltphysik, Universität Heidelberg

2. How large is the contribution from fossil fuels to the amount of CO 2 in the atmosphere? … from a modeller’s perspective

3. February CO 2 Fluxes Biome-BGC NEE (Churkina et al., 2003) 10 -9 kg C m -2 s -1 01020304050-10 February 2002annual mean 2000 Fossil fuel CO 2 (EDGAR V3.2 FT, Olivier et al., 2005)

4. Heidelberg: February 2002 (REgional MOdel)

5. Heidelberg: June 2002 (REgional MOdel)

6. Schauinsland: February 2002 (REgional MOdel)

7. Fossil fuel experiment Objective: Assess the impact of new « hourly estimates » of fossil fuel emissions over Europe at continental sites using different transport models Inventories: TransCom 3 EDGAR ft 2000 yearly EDGAR ft 2000 hourly IER 2000 hourly Models: LMDz TM5 TM3 DEHM REMO

8. Fossil fuel experiment FebMarJanAprMayJunJulAugSepOctNovDec 2002

9. How to measure fossil fuel CO 2 in the atmosphere? —› Radiocarbon ( 14 C) in atmospheric CO 2 … … because fossil fuel CO 2 contains no 14 C and dilutes atmospheric 14 CO 2

10. 14 CO 2 monitoring sites in (Carbo)Europe Paris Lutjewad Heidelberg Schauinsland Jungfraujoch Krakow Kasprowy Mace Head REMO mean european fossil fuel CO 2 in January 2002 at 130m [ppm]

11. Measured CO 2 (foss) mixing ratio Data provided by R. Neubert (Lutjewad) and K. Rozanski (Krakow) 35 30 25 20 15 10 5 0 35 30 25 20 15 10 5 0 20 15 10 5 0 543210543210  CO 2 fossil fuel [ppm] Comparison with REMO 35 30 25 20 15 10 5 0 35 30 25 20 15 10 5 0 20 15 10 5 0 543210543210  CO 2 fossil fuel [ppm]

12. Measured CO 2 (foss) mixing ratio Geels et al., 2005, CO 2 model comparison Comparison with models  CO 2 fossil fuel [ppm] 12 10 8 6 4 2 0 -2 20 15 10 5 0 -5 JULY – 1998 DECEMBER – 1998 mhd cbw sch jfjhei hun pal tvr prs mhd cbw sch jfjhei hun pal tvr prs TM3 LMDZ HANK DEHM REMO OBS

13. … but the network of 14 C measurements is sparse: 8 - 10 stations across Europe … and the temporal resolution is poor: weekly means 14 C is an excellent tracer for fossil fuel CO 2

14. —› proxies/surrogates needed to substitute 14 CO 2 observations Carbon Monoxide (CO)

15. CO/CO 2 fossil fuel emission ratios 2000 EDGAR V3.2 FT 2000 (Olivier et al., 2005) mmol / mol 1020304050600 annual mean emissions on global 1°x1° grid IER mean 2000 (Scholz et al., IER 2005) hourly emissions on 50 km x 50 km grid

16. Comparison of measured and REMO-modelled atmospheric CO and CO 2 (foss) CO and CO 2 (foss) corrected with 222 Rn(obs)/ 222 Rn(mod)

17. Comparison of measured and REMO-modelled CO/CO 2 (foss) ratios Mean ratios [ppb/ppm]: Observations: 13.5±2.5 REMO & EDGAR: 12.7±0.6 REMO & IER: 11.0±0.8 CO 2 (foss) corr RMSE [%] REMO & EDGAR: 21.4 REMO & IER: 42.7

18. Conclusions (I):  Fossil fuel CO 2 emissions in Europe contribute almost half to the continental CO 2 signal.  Monthly mean fossil fuel CO 2 levels at urban sites can be determined by high precision 14 CO 2 measurements to better than ±10% in winter and about ±30% in summer.  At remote sites, the mean fossil fuel CO 2 signal is small (1-5 ppm) and can be determined by 14 CO 2 measurements only to about 30%.  14 C-derived fossil fuel CO 2 at selected stations is needed to validate emissions inventories and assess model estimates of fossil fuel CO 2.

19. Conclusions (II): CO is a potentially applicable surrogate tracer for fossil fuel CO 2, however,  Emissions inventories of CO and fossil fuel CO 2 are yet not accurate enough to apply it quantitatively,  Non-fossil CO sources, in particular soil emissions and their temporal variations, strongly influence the results and need to be estimated more accurately,  The catchment area and relative mix of emissions needs to be known accurately, this requires modelling,  Validation at a larger number of sites is necessary e.g. at one site per country, at least in Europe.

20. Thank you !

21. Radiocarbon 14 C ( 14 C, radioactive life time  = 8300 years) Natural 14 C production by reactions of neutrons from cosmic radiation with atmospheric Nitrogen  natural atmospheric background level Artificial 14 C production via atmospheric nuclear weapon tests in the 1950s and 1960s „Negative 14 C source“ via burning of fossil fuels and cement production

22. Long-term 14 CO 2 observations in Europe „clean“  14 CO 2 background level in the Alps Depletion of the  14 CO 2 level close to fossil fuel sources Suess effect bomb tests

23. Monthly mean fossil fuel CO 2 at Schauinsland station and in Heidelberg mean fossil fuel CO 2 offset: Schauinsland: ca. 1.4 ppm Heidelberg: ca. 10 ppm

24. Regional Atmospheric Model REMO  0.5° x 0.5° horizontal resolution  20 vertical layers  Semi-hemispheric model domain (> 30°N)  Online tracer transport  Prescribed emissions and surface fluxes  Parameterization of CO chemistry  Initial and lateral boundary conditions: Metorology: ECMWF analyses CO:MOZART global CTM (Horowitz et al., 2003) CO 2 :TM3 global transport model (Heimann and Körner, 2003)

25. Surface fluxes used in REMO  CO Emissions  Fossil fuel burning (EDGAR V3.2 extrapolated)  Fossil fuel burning in Europe (IER 2000, extrap.)  Fuelwood burning (EDGAR V3.2)  Agricultural waste burning (EDGAR V3.2)  Biomass bruning (Hao and Liu, 1994)  Soil emission (Müller, 1992)  Ocean emission (Brasseur et al., 1998)  CO 2 Surface fluxes  Fossil fuel burning (EDGAR V3.2 extrapolated)  Fossil fuel burning in Europe (IER 2000, extrap.)  Terrestrial Biosphere Model BIOME-BGC (Churkina et al., 2003)  Ocean fluxes (Takahashi et al., 1999)

26. Comparison of measured and REMO-modelled CO/ffCO 2 ratios Mean ratios [ppb/ppm]: Observations: 13.5±2.5 REMO & EDGAR: 12.7±0.6 REMO & IER: 11.0±0.8 EDGAR (only FF): 11.2 IER (only FF): 12.4

27. Comparison of measured and REMO-modelled CO/CO 2 (foss) ratios EDGAR(only foss):34.4 IER(only foss): 28.8 Mean ratios [ppb/ppm]: Observations: 13.5±2.5 REMO & EDGAR: 12.7±0.6 REMO & IER: 11.0±0.8 CO 2 (foss) corr RMSE [%] REMO & EDGAR: 21.4 REMO & IER: 42.7

28. Measured CO 2 (foss) mixing ratio Data provided by R. Neubert (Lutjewad) and K. Rozanski (Krakow) Comparison with REMO 35 ppm 5 ppm 20 ppm 35 ppm