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A multi-model assessment of

A multi-model assessment of. Hemispheric Transport of Air Pollution. Frank Dentener, Arlene Fiore, Michael Schulz, Martin Schultz, Oliver Wild, HTAP modellers. + observations. Convention of UNECE (United Nations Economic Commission for Europe)

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A multi-model assessment of

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  1. A multi-model assessment of Hemispheric Transport of Air Pollution Frank Dentener, Arlene Fiore, Michael Schulz, Martin Schultz, Oliver Wild, HTAP modellers + observations

  2. Convention of UNECE (United Nations Economic Commission for Europe) • The Convention addresses major environmental problems of the UNECE region • The Convention has 51 Parties (European countries + USA + Canada) • 8 protocols identify specific measures to be taken by Parties to cut their emissions of air pollutants (e.g. EMEP Protocol) • Parties develop policies and strategies to combat the discharge of air pollutants through exchanges of information, consultation, research and monitoring.

  3. TF HTAP • The Task Force on Hemispheric Transport of Air Pollution was established in December 2004. • The Task Force estimates the hemispheric transport of: • ozone and its precursors • fine particles • acidifying substances • mercury • persistent organic pollutants • Hemispheric transport may be important for understanding air pollution problems in population centers and impacts on remote areas. • The Task Force reports its findings to the Convention’s Steering Body of EMEP. • HTAP has initiated a comprehensive modeling study to assess the importance of intercontinental transport of air pollution.

  4. www.htap.org HTAP Interim report: June 2007 (downloadable). Final report: Middle of 2009. TF HTAP jointly chaired by US EPA, EC/DG ENV.

  5. EU NA EA SA Experiment Set 1 Source Receptor Relationships     F. Dentener, A. Fiore • First insight about the importance and uncertainties of hemispheric transport processes for ozone and its precursors, particulate matter • Using ‘best’ emission inventory and meteorological dataset for 2001. • Simulations consist of a reference simulation (2001), and simulations reducing their anthropogenic emissions per region by 20 %. • The four regions of interest for Source Receptor Relationships are Europe, North America, East Asia and South Asia. • >20 models participated in Experiment 1, 5 more in the SR1 only

  6. Experiment Set 1 www.htap.org EU NA EA SA 1. SR1 = base case (methane prescribed 1760 ppb) 2. SR2 = global methane reduction by 20% (1408 ppb) 3. 4x SR3 = regional NOx reduction by 20% 4. 4x SR4 = regional NMVOC reduction by 20% 5. 4x SR5 = regional CO reduction by 20% 6. 4x SR6 = regional reduction of all anthropogenic emissions by 20% ________________________________________________________ 18 experiments in total (each at least 18 months simulation time)

  7. Other experiments • Experiment Set 2: Processes and tracer studies (M. Schultz, O. Wild & D. Shindell) • To develop a simple set of diagnostics that can be used to understand the model differences that occurred under Experiment 1. • Experiment Set 3: Detailed experiments for Mercury, Ozone, Aerosols, POPs,  linkage to campaigns (I. Bey), climate change, regional scale issues. • There are a number of issues relevant for HTAP, that can be studied with coordinated experiments. These experiments will asses in more details processes relevant for HTAP. • Experiment Set 4: Improved sets of Source Receptor experiments • Yet to be defined, further assessment and future scenarios

  8. 1x1 for each region 3x2 nhe 6x4 global Which resolution do we choose?

  9. Global NOx and VOC emissions

  10. Seasonal cycles in simulated surface O3 over the HTAP regions SR1 results from 20 individual models including 5 „twins“ Model range spans ~15-30 ppbv

  11. Seasonality: Monthly mean surface O3 changein EU from 20% reductions of domestic NOx emissions  Large seasonality masked by annual mean statistic

  12. Intercontinental Ozone SR relationships Ozone Response [ppbv] in Receptor regions due to 20 % ant. Emission reduction

  13. Intercontinental Ozone SR for Europe “foreign” “foreign” “foreign” “foreign” • 20 % perturbation of anthropogenic emissions in specific regions • Combined influence of 3 foreign regions emission reductions similar to • that in the domestic regions • NOx and VOC have the greatest influence- weak non-linearity • Ratio Emission NOx/Emission VOC=0.24±0.11

  14. Intercontinental Ozone SR for North America “foreign” “foreign” “foreign” “foreign” • NOx the greatest influence • Ratio Emission NOx to Emission VOC=0.15±0.06: half that of Europe • Combined influence of 3 foreign regions emission reductions half to • that in the domestic regions

  15. NOy deposition: Source-Receptor analysis Where do NO emissions from Europe go to?

  16. NOy deposition: Receptor-Source analysis If we would change NO emissions in all 4 regions by 20 %; how would it influence a receptor region?

  17. PM receptor analysis

  18. Perturbation experiments for 4 world regions: NOx, CO, VOC, SO2, EC, POM, CO (Hg Pops). Model spread in perturbation signal typically factor of 2 Ozone sensitivities ca. 1.5-2 ppbv to 20% ant. emission reduction in all 4 regions NA>EU twice as large as all other SR relations Role of methane is an open issue Resolution dependency of seasonal differences Episode analysis Tracer experiments indicate that BL mixing among models varies between 40% and 80% Relatively much attention to interoperability; CF conventions Conclusions

  19. The first phase of HTAP had very little focus on observations However, most models participated previously in PHOTOCOMP and AEROCOM intercomparisons (2004-2006) Tight timeschedule It was felt that the models in HTAP would not give very different results AEROCOM (http://nansen.ipsl.jussieu.fr/AEROCOM/) Considers surface chemistry observations; satellite AOD/Angstrom, Aeronet, EARLINET. AEROCOM workshop 25/26 October, Lille. The role of observations

  20. Sonde data: Logan (1999) + SHADOZ (Thompson et al, 2003 ) Sonde ± 1SD Model ± 1SD UT: 250 hPa J F M A M J J A S O N D Stevenson et al., JGR, 2005 MT: 500 hPa LT: 750 hPa 90-30S 30S-EQ EQ-30N 30-90N Ensemble mean model closely resembles ozone-sonde measurements

  21. Monthly average Surface ozone comparison with measurements S.W. US S.E. US Great Lakes N. China Brazil C.E. Africa S. Africa • Max models • + 1 sd • 1 sd • Min models C. Mediterranean C. Europe N. India; Nepal Middle East S. India S.E. Asia Ellingsen et al, ACPD, 2007

  22. CO comparison with MOPITT NH GLOBAL “Individual models” SH TROPICS Shindell et al, JGR, 2006

  23. NO2 column: retrievals and models Van Noije et al, ACP, 2006

  24. HNO3 wet deposition: models and measurements EMEP NADP Kulshrestha EAnet IDAF Various Galloway Dentener et al., GBC, 2006

  25. Next phase of HTAP(2007-2009): • Climate, regional, tracer experiments=>2009 report. • More linkage to observations; e.g. model experiments are planned focusing on campaigns: TRACE-P; ICARRT-INTEX. The base years for consideration are 2001/2004. • Strong need for accepted ‘benchmark’ datasets, to which models and their updates can be routinely compared. QA-QC; fit-for-purpose. • What are the quality criteria for these benchmark datasets? • Interoperability of model data will help. • NILU will select surface observations for establishing benchmark datasets • Satellite data?

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