The robustness of the source receptor relationships used in GAINS Hilde Fagerli, EMEP/MSC-W EMEP/MSC-W

Norwegian Meteorological Institute met.no Outline Where do the uncertainties in S-R relationships come from and can they be validated? What main changes in the EMEP model have been done? How do these changes influence S-R relationships?

Norwegian Meteorological Institute met.no Where do the uncertainties in the S-R relationships come from ? Input data; Meteorology, Emissions (land and ship) ‏ Meteorological variability Uncertainties in the chemical transport model itself (chemical processes, dry and wet removal, transport).

Norwegian Meteorological Institute met.no EMEP/MSC-W Very small effect of scale in meteorology Larger effect of redistribution of emissions -in this case the lack of oil installations in the north sea in the TNO data

Norwegian Meteorological Institute met.no Where do the uncertainties in the S-R relationships come from ? Input data; Meteorology, Emissions (land and ship) ‏ Meteorological variability Uncertainties in the chemical transport model itself (chemical processes, dry and wet removal, transport).

Norwegian Meteorological Institute met.no The S-R relationships themselves cannot be validated, but the model results can (in many cases) ‏ Validation of air concentrations and wet depositions Validation of trends (response to changes in the chemical climate) ‏ Some processes more uncertain than others: –E.g. dry deposition –Vertical mixing –Gas-particle partitioning, e.g. for nitrate-nitric acid –SOA (not included) ‏

Norwegian Meteorological Institute met.no Comparison of the EMEP model and other models – response to emission changes (EuroDelta II) ‏ Comparison of the potency of emission reductions of NOx, SO2, NH3 and PPM from Spain, as calculated by the different models (Model 3=EMEP). Potency averaged over EU-25

Norwegian Meteorological Institute met.no What changes have been done in the EMEP model (since the S-R used in GAINS) ? Nitrate chemistry Meteorological driver But there are other changes coming....since the model is continuously improved!

Norwegian Meteorological Institute met.no Change 1. Update of the N2O5 hydrolysis Result: Less conversion of N2O5 to HNO3 and consequently less formation of nitrate aerosols (more NO2) ‏ Largest effect for countries with high NOx and NH 3 emissions Difference in total nitrate between version with and without upgraded nitrate formation, new- old (%) ‏

Norwegian Meteorological Institute met.no Consequence for S-R matrices Consequence for S-R matrices: More NO 2, less HNO 3, NO 3 -. Somewhat more long-range transport of oxidized nitrogen PROBLEM: Nitrate is difficult! SE 2.3 NL DK DE BE OLD model (%) ‏ NEW model (%) ‏ Percentage of emissions from the country that is deposited within the country itself (OXN), 2005

Norwegian Meteorological Institute met.no Change 2. Change of meteorological driver from PARLAM-PS to HIRLAM Why? –More updated science in new HIRLAM version –Increased model domain to include EECCA countries Better performance in terms of spatial and temporal correlations, but more negative bias for SIA

Norwegian Meteorological Institute met.no Pollution export, example: export of SOx from GB Large terms rather robust Transport over sea (e.g. UK to NO or SE) more sensitive ‘NWP Variability’ smaller or similar to met. variability

Norwegian Meteorological Institute met.no Pollution import, example: import to Germany and Norway (PPM2.5) ‏ The results are normalized to H Germany Norway

Norwegian Meteorological Institute met.no Summary, change of NWP No systematic changes For large countries the ‘NWP uncertainty’ is smaller than for small countries (met. average out changes) ‏ The relative uncertainty is larger for small contributions, whilst the results for large contributions are relatively robust In general; uncertainty smaller or comparable to met variability

Norwegian Meteorological Institute met.no Conclusions The 'accuracy' of the S-R relationship depends on both input data (e.g. emissions, meteorology) and the chemical transport model The most important changes in the EMEP model is the updated nitrate formation and the meteorological driver The update of the N2O5 hydrolysis has led to somewhat more long range transport of OXN The change of meteorological driver: Non- systematic. The large terms are relatively robust, but smaller terms are more uncertain

Norwegian Meteorological Institute met.no The end

Norwegian Meteorological Institute met.no To what extent can we trust the S-R relationships? Changes made in the EMEP model the last year How these changes influence S-R relationships Whether the EMEP workplan has influenced the SR matrices in use

Norwegian Meteorological Institute met.no Same as above but with potencies averaged over Spain, the emitter country. Note that secondary y-axis refers to Primary Particulate Matter.