1. 12 th ICMGP, Jeju, Korea, 2015 Multi-model assessment of mercury cycling in the atmosphere Oleg Travnikov, Johannes Bieser, Ashu Dastoor, Carey Friedman, Ian Hedgecock, Volker Matthias, Andrew Ryzhkov, Noelle Selin, Francesco De Simone, Shaojie Song, Xin Yang Environment Canada

2. 12 th ICMGP, Jeju, Korea, 2015 GMOS Mercury Modelling Task Force Hg processes in the atmosphere Global Mercury Observation System (GMOS) Objectives: Multi-model study of Hg emissions and atmospheric processes Assessment of Hg intercontinental transport and future scenarios Evaluation of model performance using GMOS measurement data Aircraft measurements RV Urania Marine cruisesGround-based sites Hg measurements within GMOS

3. 12 th ICMGP, Jeju, Korea, 2015 Base run Simulation with the state-of-the-art model configuration (BASE) MMTF model experiments Emission effects Model run with no anthropogenic emissions (NOANT) Modified speciation of Hg anthropogenic emissions (ANTSPEC) Unified natural/secondary emissions (COMNAT) Improved emissions base on inverse modelling (INVEMI) Atmospheric chemistry Model run with no atmospheric chemistry (NOCHEM) Simulation with Br oxidation chemistry with two different sets of Br air concentration (BRCHEM1 and BRCHEM2) Simulation with OH - initiated oxidation chemistry (OHCHEM) Simulation with O 3 - initiated oxidation chemistry (O3CHEM)

4. 12 th ICMGP, Jeju, Korea, 2015 MMTF model experiments Source region apportionment Evaluation of Hg dispersion from 14 major source regions (Europe, North America, East Asia, South Asia etc.) Emission sectors apportionment Evaluation of Hg dispersion from 3 groups of emission sectors (stationary combustion, industrial sources, intentional use) Study setup Anthropogenic emissions: AMAP/UNEP inventory for 2010 Natural/legacy emissions: Model specific Target year: 2013

5. 12 th ICMGP, Jeju, Korea, 2015 Participating chemical transport models (CTM): ModelScaleInstitution GLEMOSglobal/regionalEMEP/MSC-E ECHMERITglobalCNR-IIA (Italy) GEM-MACH-HgglobalEnvironment Canada GEOS-ChemglobalMIT (USA) CMAQ-HgregionalHZG (Germany) WRF-ChemregionalCNR-IIA (Italy) p-TOMCATglobalCambridge (UK) GMOS Mercury Modelling Task Force

6. 12 th ICMGP, Jeju, Korea, 2015 Participating chemical transport models (CTM): ModelScaleInstitution GLEMOSglobal/regionalEMEP/MSC-E ECHMERITglobalCNR-IIA (Italy) GEM-MACH-HgglobalEnvironment Canada GEOS-ChemglobalMIT (USA) CMAQ-HgregionalHZG (Germany) WRF-ChemregionalCNR-IIA (Italy) p-TOMCATglobalCambridge (UK) GMOS Mercury Modelling Task Force

7. 12 th ICMGP, Jeju, Korea, 2015 Location of monitoring sites Measurement data Monitoring networks: Global GMOS network for Hg Regional Hg networks (EMEP, NADP/MDN) Regional Hg networks (AMNet, NAtChem) GMOS partners: Measurement data used for the analysis (2013) GEM/TGM in air (28 sites) Wet deposition (135 sites) GEM, GOM, PBM in air (11 sites)

8. 12 th ICMGP, Jeju, Korea, 2015 Model experiments: BASE run GLEMOS GEOS-Chem GEM-MACH-HgECHMERIT Hg 0 air concentration (2013)

9. 12 th ICMGP, Jeju, Korea, 2015 GLEMOS GEOS-Chem GEM-MACH-HgECHMERIT Model experiments: BASE run Hg wet deposition (2013)

10. 12 th ICMGP, Jeju, Korea, 2015 Inter-hemispheric gradient GLEMOS GEOS-Chem GEM-MACH-HgECHMERIT Zonal-mean distribution of Hg 0 concentration 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM BASE runNo chemistryNo anthrop. emissionMeasurements The inter-hemispheric gradient of Hg concentration is largely defined by atmospheric chemistry and natural/legacy emissions

11. 12 th ICMGP, Jeju, Korea, 2015 Inter-hemispheric gradient Hg + Br (1)Hg + O 3 Hg + OHMeasurements 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM 0.5 1.0 1.5 -90-60-300306090 Latitude Normalized GEM Hg + Br (2) GLEMOS GEOS-Chem GEM-MACH-HgECHMERIT Zonal-mean distribution of Hg 0 concentration 1 10 100 1000 -90-60-300306090 Latitude Br concentration, ppq Br concentration GEOS-Chem p-TOMCAT Both Br and OH chemistry allows reproducing inter-hemispheric gradient. Available data on Br air concentration is highly uncertain

12. 12 th ICMGP, Jeju, Korea, 2015 Inter-hemispheric gradient 0 1 2 3 4 -90-60-300306090 Latitude Normalized wet deposition 0 1 2 3 4 -90-60-300306090 Latitude Normalized wet deposition 0 1 2 3 4 -90-60-300306090 Latitude Normalized wet deposition GLEMOS GEOS-Chem GEM-MACH-Hg Zonal-mean distribution of Hg wet deposition Hg + Br (1)Hg + O 3 Hg + OHMeasurements Precipitation Br and OH/O 3 mechanisms produce significantly different distributions of wet deposition in ITCZ and Southern Hemisphere. More measurements are needed in these regions

13. 12 th ICMGP, Jeju, Korea, 2015 Seasonal variation Mean seasonal variation of Hg wet deposition (Europe) 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition GLEMOS GEOS-Chem GEM-MACH-Hg BASE runNo chemistryNo anthrop. emissionMeasurements Seasonal variation of Hg wet deposition in Europe is mostly defined by oxidation chemistry

14. 12 th ICMGP, Jeju, Korea, 2015 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition Seasonal variation 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition 0.0 0.5 1.0 1.5 2.0 JanFebMarAprMayJunJulAugSepOctNovDec Normalized wet deposition GLEMOS GEOS-Chem GEM-MACH-Hg Hg + Br (1)Hg + O 3 Hg + OHMeasurementsHg + Br (2) Mean seasonal variation of Hg wet deposition (Europe) OH-initiated chemistry better reproduces seasonal cycle of wet deposition in Europe

15. 12 th ICMGP, Jeju, Korea, 2015 Source apportionment Source/receptor regions EuropeAfrica Middle East North America Central America South America South Asia East Asia Southeast Asia Australia and NZ CIS countries Antarctica Arctic Europe Australia and NZ Africa Arctic South America South Asia Middle East North America East Asia Source apportionment of Hg anthropogenic deposition

16. 12 th ICMGP, Jeju, Korea, 2015 Update of modelling results in GMA 2013 Available online: http://www.amap.no/documents/doc/global-mercury-modelling-update-of- modelling-results-in-the-global-mercury-assessment-2013/1218 Published by UNEP & AMAP Contents: Global patterns of mercury air concentration and deposition Estimates of mercury intercontinental transport Mercury deposition from different emission sectors

17. 12 th ICMGP, Jeju, Korea, 2015 Preliminary conclusions The inter-hemispheric gradient of Hg 0 concentration is largely defined by atmospheric chemistry and natural/legacy emissions Both Br and OH chemistry allows reproducing inter-hemispheric gradient of Hg 0. However, available data on Br air concentration is highly uncertain Br and OH/O 3 mechanisms produce significantly different distributions of wet deposition in ITCZ and Southern Hemisphere. More measurements are needed in these regions Seasonal variation of Hg wet deposition in Europe is mostly defined by oxidation chemistry OH-initiated chemistry better reproduces seasonal cycle of wet deposition in Europe

18. 12 th ICMGP, Jeju, Korea, 2015 Further plans Involve speciated Hg measurements to evaluate GOM and PBM concentrations Use highly temporally resolved (hourly) data to analyze diurnal variation of GEM, GOM and PBM concentration Utilize the CARIBIC data to evaluate TGM distribution in upper troposphere Provide open access to the MMTF model simulations data through the GMOS Spatial Data Infostructure