1. Optical characteristics of aerosol across Europe (WP2.2) Dry/wet aerosol optical properties (and how we got there) Optical closure (agreement between Mie modelled scattering/absorption starting from chemical composition information, and in-situ measured scattering and absorption)

2. Optical depth in EUCAARI

3. Single scattering albedo (SSA) in ADIENT/EUCAARI Wet SSA calculated using ambient RH and campaign average hygroscopic growth curve to scale measured scattering

4. During (largely) spring time anticylonic event… AOD gradient from east to west with AOD increasing (contributing factors aging, RH, emissions, increase in proportion of nitrates towards west) SSA more consistently between 0.93 and 0.97; lower values near known fresh plumes, higher values more spread out (c.f. previous work: ADRIEX mean 0.92, TARFOX 0.87, ACE2 0.94) Issue about B368 and the Baltic… real or not…

5. SSA in EUCAARI – including Baltic points (note different colour scale from previous plot) Should we include/not include flight B368 in Baltic?

6. Optical closure (scattering) in ADIENT/EUCAARI

7. Optical closure (absorption) during ADIENT/EUCAARI

8. Scattering closure is pretty good (i.e. within 30%) – slight bias towards model underestimation, but PCASP potentially undersamples… Absorption not quite so good but probably larger uncertainties on PSAP and SP2…

9. Where next? Writing up paper using all available data (should ADIENT Sept flights and June this year flights be included, or should it just concentrate on the anticyclonic event from EUCAARI?) Comparison with ground sites (AERONET and (for September flights) Weybourne Lidar Analysis of future flights and linking to likely processes, chemical composition etc