Modelling of atmospheric deposition and global mapping

Transcription

1 Modelling of atmospheric deposition and global mapping Frank Dentener, EC, Joint Research Centre. Silvina Carou, WMO. Global Atmosphere Watch Workshop on Measurement-Model Fusion for Global Total Atmospheric Deposition (MMF-GTAD) February 28 - March 2, WMO Geneva

2 Outline Recent global modelling benchmark studies WMO GAW workshop on model-measurements fusion Recommendations

3 Recent model intercomparison exercises Exercise Photocomp 2006 HTAP Custom er AR4 UNECE/L RTAP Themes Air pollution-deposition new theme: scenarios. Ensemble. Model evaluation. 10 models. Ensembles. Hemispheric Transport (2001). Link to WMO SAG DEP: global picture/evaluation. 20 models ACCMIP AR5 Climate model simulations ca 5-10 models HTAP2 AQMEII- EURODelta UNECE/L RTAP UNECE/L RTAP Hemispheric transport (2010). Ongoing. More focus on land-use characterisation Regional version of HTAP2. North America and Europe. MICS-Asia Regional- Asian deposition. 8 models

4 Photocomp: HNO 3 +NO3 p wet deposition: models and measurements: year 2001 EMEP NADP EAnet CAD Various IDAF # Observations in circles Keene, Galloway Ensemble model almost always better than individual models Aggregated observations in latitude bands to remove variability that can not be reproduced in models Best agreement in North America, then Europe, and mixed results in Asia, Africa,. Less models for NH4, and especially over South Asia large discrepancy. Dentener et al, 2006

5 Vet et al. 2014, HTAP1 WMO Global Deposition Assessment Objectives: Global and regional picture of precipitation chemistry and wet, dry, total deposition of sulfur nitrogen, seasalt, dust organic acids, acidity, and phosphorous Identify Knowledge gaps. Use HTAP1 ensemble model to provide information in regions where no observations were available- including budget analysis. Focus on N and S components. Demonstration the usefulness of data to identify model weaknesses. Main results (reg. models): Total deposition is almost entirely relying on model estimates. Dry/total global deposition patterns mimic wet deposition Sulfur total deposition overestimated in Europe and North America- N- deposition looks better. Industrialized regions NOy deposition larger, but elsewhere N-dep dominated by NHx. Model gaps: limit the use of these models in undersampled regions of the globe.

6 Vet et al. 2014, wet dry and total deposition over North America Wet deposition looks realistic, but dry and total deposition are overestimates TF HTAP ensemble-mean modeling results may overpredict dry deposition and its % contribution to total deposition in Europe.

7 ACCMIP, Lamarque et al ACCMIP informing IPCC s AR5 report Chemistry climate models 5-10 climatological years Timeslices from Upto 10 models NOy, 2-5 models NHx. Emissions from a shared RCP (historical and future) database Compare 2000s with observations from WMO s (Vet et al. 2014) assessment Compare to icecores, and deposition trends between Very similar performance statistics between ACCMIP, HTAP1, and Photocomp Models did not improve much? Are emission inaccuracies the main factors driving the differences?

8 ACCMIP, Lamarque et al. 2013, observed and modelled change in Nitrate NH4, and SO4 deposition between Changes larger in observations than in models (for all components) S-changes captured well in Europe The large changes in nitrate/nh4 E.in Europe and Russia only partly corroborated by observations Reflecting mostly emissions not changes in chemistry or climate

9 HTAP2: Global & Regional Source/Receptor Modeling Overall Approach: Use global and regional simulations of to evaluate against observations and to contribute to the quantification of parameterized S/R relationships. Use parameterized S/R relationships to estimate impacts of future strategies. World divided into 16 Regions (60 sub-regions) AQMEII AQMEII MICS Asia 7 priority source regions: North America, Europe, East Asia, South Asia, Russia/Belarus/Ukraine, Middle East Ca. 10 global models Consistent Nested Regional simulations from AQMEII and MICS-Asia Opportunity to get consistent global deposition maps with more resolution over North America and Europe Sensitivity Experiments: Pollutants: CH 4, NOx, CO, VOC, aerosol-(precursor) Sectors: Transport; Power/Industry; Residential; Other, Fires/Dust

10 HTAP2: modelled wet NO3 deposition in 2010 Ca. 5 models delivered deposition results for various perturbations 3 models delivered land-cover information. Work planned for analysis of O3 deposition, inorganic deposition in frame of WMO model-measurements data-fusion

11 AQMEI3: 2010 AQMEII3: Regional models with boundary conditions from global models. Evaluate the difference in regional/global models with regard to deposition processes Christian Hogrefe, Workshop MMF-TAD, WMO, 2017

12 MICS-ASIA-3 Siuichi Itahashi, workshop MMF_TAD, WMO 2017

13 MMF-GTAD Workshop Objectives and outcomes Objective: To review the state-of-the-science on Measurement-Model Fusion for Global Total Atmospheric Deposition and establish a GAW project for the purpose of generating global maps of total atmospheric deposition, important atmospheric gases, and particles Science presentations and panel discussions focused on: o Existing MMF-TAD projects and activities worldwide o Surface and satellite measurements o Global/hemispheric and regional modelling, evaluation and comparability (HTAP2, AQMEII3, MICS3, ECMWF/Copernicus) Buy-in from major modelling and measurement groups including GAW Scientific Advisory Groups, and clear link to policy and science driver

14 MMF-TAD Approach Measured precipitation concentrations Modelled precipitation concentrations Measured air concentrations Modelled air concentrations Fusion method Fusion method Precipitation concentration maps Air concentration maps Wet deposition maps Total deposition maps Dry deposition maps Modelled dry deposition of unmeasured species Precipitation depth map Measured precipitation depth Fusion method Modelled precipitation depth Modelled dry deposition velocities

15 Key conclusions: Measurements Need to extend the GAW measurement network into regions that are presently poorly covered (e.g. intensive measurements at supersites). Organic nitrogen, ammonia, nitrogen oxides, iron (over the ocean) and dust deemed highest priority globally for measurement in new and/or existing networks. Publicly-available, integrated, high quality global data sets were identified as critical to the success of the MMF-GTAD Project. Need to establish consistency in methods for estimating/measuring dry deposition (e.g. a common inferential modelling framework) Satellite measurements and their products are evolving rapidly and should be included in future measurement-model fusion activities. All available measurements should be further exploited and understood.

16 Key conclusions: Modelling A significant body of chemical transport modelling work exists and is suitable for use in a future MMF-GTAD Project (including HTAP, AQMEII, EMEP, etc.). Most models of deposition did not progress a lot in the last 2 decades Some aspects of deposition modelling are still very uncertain, including land use and dry deposition schemes in models and emissions data. Need to better link land use/land cover to deposition in order to understand the sensitivity and response of receptors to deposition. Need to use new techniques (e.g. inverse modelling) to improve emissions, as well as satellite data as potentially valuable for small emission corrections (e.g., updating emission inventories to a more recent year) and for deducing natural sources. When providing the 'best estimate' of total (dry+wet) deposition, it is important at the same time to make uncertainty estimates and constrain the results (i.e. consistency with emissions)

17 Major Outcomes: 3 Phase project Initial focus on S, N and O 3. Phase 1 Short Term. MMF of existing 2010 ensemble global model results with existing data sets (HTAP, AQMEII). Products: comprehensive data set and model ensemble output files and gridded MMF maps. Phase 2 Medium Term. Stitching together existing and new regional/global MMF-TAD maps (Canada, USA, UK, Sweden, Norway, Asia, Europe) to produce global maps + a journal article Phase 3 Long Term. Ongoing operational re-analysis using data assimilation (ECMWF/Copernicus/CAMS) Ad Hoc Data Group to investigate workload and needs for gathering data from existing science assessments modelling activities Buy-in from major modelling and measurement groups including GAW Scientific Advisory Groups, and clear link to policy and science drivers Workshop Report (draft) and a Roadmap to the Future Report

18 Thank you

19 Key conclusions: International policy and science drivers Ecosystem sustainability o o UN Convention for Biological Diversity (Strategic Plan for Biodiversity and Aichi Target 8) 2015 Sustainable Development Goals (targets and indicators) Biogeochemical cycles Nitrogen o o International Nitrogen Management System International Nitrogen Initiative Human Health o o o World Health Organization (WHO Air Quality Guidelines, Global Burden of Disease Assessment) Global Platform on Air Quality and Health Climate and Clean Air Coalition Climate Change o UN Framework Convention on Climate Change i.e. through carbon cycle, or co-benefits of reducing N2O emissions.