1. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Task Group 3 Achievements and Prospects Ankie Piters, KNMI

2. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Activities 2005/6: Participation in Dandelions campaigns 2006: CO session during AT2  Recommendations 2007: Tropospheric NO 2 workshop (inter-TG)  Recommendations 2007/8: Investigate what is needed to assess accuracy of MAX-DOAS trop. NO 2 profiles  campaign in GEOMON/CEOS framework

3. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Trop. NO 2 validation, latest results within TG3 (also: Brunner et al, Masieri et al  talks today)

4. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Comparison with MAXDOAS OMI and SCIAMACHY tropospheric NO 2 have good agreement with MAXDOAS Dandelions data set (3 instruments) Brinksma et al, JGR, 2008 Schönhardt et al, 2007 Estimated uncertainty: 30-50%

5. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Spatial representativity  high spatial inhomogeneity Brinksma et al, JGR, 2008 Ratio of maximum and minimum SCD versus time when looking in different directions

6. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 MAXDOAS/in-situ/NO2lidar intercomparisons  What is the accuracy of the different correlative instruments? Wittrock et al, NO2 workshop, 2007

7. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Recommendations from NO 2 workshop Determine accuracy of (mini-)MAXDOAS and NO 2 lidar in campaign Have mobile campaigns through China (distance to source) Validate input data used in the retrievals (surface albedo and trop. profile) Small campaigns for special situations: e.g. snow/ice + pollution Establish (mini-)MAXDOAS network for long-term satellite validation Combine models, in-situ surface and RS measurements for validation Make better use of available (validation) campaign data bases Join planned campaigns with additional tropospheric NO 2 measurements

8. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 GEOMON/CEOS campaign Objective: intercomparison of NO 2 measuring instruments, characterisation of uncertainties Including a blind intercomparison with referee Sponsored by ESA, NASA, GEOMON, … 6-10 (mini-)MAXDOAS, NO 2 lidar, in-situ instruments (0- 200m), UV-Vis RS instruments Groups from Europe, USA, (Asia) Probably in Cabauw/NL (other options still open) June(/July) 2009

9. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 CO validation, latest results within TG3 (also: Dils et al  talk today)

10. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 CO validation achievements FTIR Paramaribo (Surinam): 7 campaigns in the dry seasons Comparison of CO to MOPITT (red circles) shows general good agreement CO plumes from forest fires detected in both data sets, not in model (green dots) Notholt et al, 2008

11. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 MOPITT CO is generally larger than SCIAMACHY CO, which is again larger than modeled values, notably in the NH Consistent with the Northern Hemisphere bias demonstrated in many CTMs (Shindell et al, 2006) de Laat et al, 2008

12. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 CO recommendations (2006) Exploit the use of aircraft data (e.g. MOZAIC,  limited to polluted areas?) for validation Exploit the synergetic use of in-situ surface with models Use mobile FTS for measurements near source areas Have instruments or campaigns at high-albedo places Did any of these have a follow-up yet?? FTIR data sparse, often at high altitude or near sea

13. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Other results within TG3

14. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Acetylene: C 2 H 2 (7-15km) Mahieu et al, 2008 ACE-FTS C 2 H 2 (7-15km) agrees reasonably well with FTIR partial columns ACE-FTS seems to be slightly high biased in summer

15. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Some results outside TG3

16. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 First HCHO validation Phase of seasonal variations roughly consistent FTIR observations report much larger HCHO columns especially in summer Effect of local emissions in a coastal site, not captured at the resolution of the satellite measurements? De Smedt, Van Roozendael, et al, DOAS workshop, 2008 FTIR data from N. Jones

17. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Validation needs for HCHO De Smedt, Van Roozendael, et al, DOAS Workshop 2008 Current status: in-depth validation of GOME HCHO only available for Northern US, based on aircraft data from INTEX-A campaign (Millet et al., 2006) What is needed:large scale (global) validation based on independent HCHO column measurements sampling the time/space variability of both biogenic and biomass burning emissions How can this be achieved? –Conduct more aircraft campaigns –Extend network of ground-based remote-sensing instruments (FTIR and MAXDOAS) –Use GMES/GEOSS to develop network capacities, improve data accessibility and QA/QC (cf. FP6 GeoMON) –Use model to link columns with in-situ measurements

18. Task Group 3 AT2 workshop, 30 Sept – 1 Oct 2008 Conclusions / Prospects Validation strategies and requirements for tropospheric NO 2 are well underway More can be done for validation of CO (combined campaign for IASI, MOPITT, AIRS, SCIAMACHY) Validation of cloud properties, aerosol, HCHO, trop. O 3, ……(?), could use more attention We have to move towards quantification of uncertainties and bias for tropospheric satellite products