1. TEMIS user workshop, Frascati, 8-9 October 2007 Monitoring of Transatlantic Long Range Transport of Tropospheric NO 2 – Observation and Simulation Bas Mijling Bart Dils Ronald van der A Ruud Dirksen

2. TEMIS user workshop, Frascati, 8-9 October 2007 Part 1 Observation

3. TEMIS user workshop, Frascati, 8-9 October 2007 Why tropospheric NO 2 ? – Relatively easy to measure – Relation with tropospheric O 3 Why OMI? – Daily global coverage; high resolution Why Atlantic region? – Predominant westerly winds transport air pollutants from East US to West Europe Observation LRT with satellites

4. TEMIS user workshop, Frascati, 8-9 October 2007 Basic mechanism of long range transport 1. Rapid uplift 2. Fast horizontal transport East Asian outflow of tropospheric NO 2 observed by OMI 26 May 2007

5. TEMIS user workshop, Frascati, 8-9 October 2007 Shielding effects of clouds NO 2 ghost column NO 2 above the clouds troposph. NO 2 column Surf. albedo 0.02 Cloud at 800 hPa

6. TEMIS user workshop, Frascati, 8-9 October 2007 Event I: Transatlantic NO 2 transport 2-12-20053-12-2005 5-12-2005 4-12-2005

7. TEMIS user workshop, Frascati, 8-9 October 2007 22-12-200523-12-2005 25-12-2005 24-12-2005 Event II: Transatlantic NO 2 transport

8. TEMIS user workshop, Frascati, 8-9 October 2007 6-2-20077-2-2007 9-2-2007 8-2-2007 Event III: Backflow from Europe

9. TEMIS user workshop, Frascati, 8-9 October 2007 29-7-200730-7-2007 1-8-2007 31-7-2007 Event IV: Forest fires on the Canaries

10. TEMIS user workshop, Frascati, 8-9 October 2007 Data quality: OMI collection 3 -Level 0-1: Improved dark current correction -Level 1-2: Averaged solar irradiance spectrum -Improved signal to noise ratio (noise floor now at ~0.2 10 15 molec/cm 2 ) -No cross-track gradient (no artifacts at overlapping tracks) -Still some striping problem (to be corrected for with filter) Collection 2Collection 3

11. TEMIS user workshop, Frascati, 8-9 October 2007 Part 2 Observation & Simulation

12. TEMIS user workshop, Frascati, 8-9 October 2007 OMI observation / FLEXPART simulation Flexpart, 14 Jan 2007OMI, 14 Jan 2007 OMI less sensitive to NO 2 in lower troposphere

13. TEMIS user workshop, Frascati, 8-9 October 2007 OMI observation / FLEXPART simulation Flexpart, 6 Jan 2007OMI, 6 Jan 2007

14. TEMIS user workshop, Frascati, 8-9 October 2007 http://www.temis.nl/lrt - Height dependency - Frequency (seasonality) - Quantify transport

15. TEMIS user workshop, Frascati, 8-9 October 2007 Future activities Reprocessing OMI data using collection 3 Implementation destriping filter New data-format (HDF5 instead of ASCII) Other areas (East Asia, South Africa, …) Other satellite instruments (GOME-2) Quantifying transport Correlation with background stations

16. TEMIS user workshop, Frascati, 8-9 October 2007 Thank you for your attention! See you at: