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07.04.2009 Lok Lamsal, Randall Martin, Aaron van Donkelaar Folkert Boersma, Ruud Dirksen (KNMI) Edward Celarier, Eric Bucsela, James Gleason (NASA) E.S.

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Presentation on theme: "07.04.2009 Lok Lamsal, Randall Martin, Aaron van Donkelaar Folkert Boersma, Ruud Dirksen (KNMI) Edward Celarier, Eric Bucsela, James Gleason (NASA) E.S."— Presentation transcript:

1 Lok Lamsal, Randall Martin, Aaron van Donkelaar Folkert Boersma, Ruud Dirksen (KNMI) Edward Celarier, Eric Bucsela, James Gleason (NASA) E.S. Edgerton, B. Hertsell (ARA Inc.) Y. Wang, C. Luo (Georgia Institute of Technology) Seasonal Variation of Nitrogen Oxides at Northern Midlatitudes as Inferred from Ground- and Satellite-based Observations Lok Lamsal, Randall Martin, Aaron van Donkelaar Folkert Boersma, Ruud Dirksen (KNMI) Edward Celarier, Eric Bucsela, James Gleason (NASA, GSFC) MOCA-09, Montreal, July 19-29

2 Substantial Seasonal Difference in Tropospheric NO 2 Columns: Example from GOME van Noije, ACP, 2006 Retrievals from University of Bremen, Dalhousie/SAO, BIRA/KNMI Difference in winter up to a factor of 2 Monthly tropospheric NO 2 columns over Eastern U.S. from three independent retrievals (71-90W, 35-43N) Uni Bremen BIRA/KNMI Dalhousie/SAO

3 Large Seasonal Difference in Tropospheric NO 2 Columns Among OMI Retrievals How does the actual seasonal variation look like? Which one is closer to reality? What causes the observed difference? What drives the seasonal variation? Research Questions: Monthly tropospheric NO 2 columns over the United States from OMI Standard Product (SP) DOMINO Product (DP) DP_GC  DOMINO product with stripes correction and GEOS-Chem NO 2 profiles Modified DP (DP_GC)

4 Comparison of OMI NO 2 with Surface Measurements, (B) Derive surface-level NO 2 from OMI (Lamsal et al., 2008, JGR) (A) In-situ surface NO 2 measurements from the SEARCH and EPA/AQS networks (Rural sites only)  × SEARCH (3) EPA/AQS (8)

5 Comparison of OMI-derived Emission with Bottom-up Inventory (B) Derive top-down emissions from OMI (Martin et al., 2003, JGR) (A) Updated bottom-up emission inventories VISTAS 2002 and CAC 2005 (North America) EMEP 2005 (Europe) Street 2006 (East Asia)

6 Summary of Comparison - Validation of OMI Tropospheric NO 2 SEARCH domainNorth America SEARCH, Southeastern U.S.AQS/EPA, U.S.

7 What Causes the Observed Difference? Algorithm componentStandard product (SP)DOMINO (DP)DP_GC Slant columnDOAS fit ( nm)Same as SP Stripe correction?YesNoYes Strat-trop separation Analysis of observation TM4 assimilation Trop NO 2 profileGEOS-Chem annualDaily TM4 Daily GEOS- Chem Scattering weightsTOMRADDAK Surface reflectivityGOME climatologyGOME+TOMS Surface pressureClimatologicalECMWF Cloud pressure/fractionO 2 -O 2 cloud algorithmSame as SP AMF

8 Difference Between DP and SP: Contribution of Stratosphere-troposphere Separation and AMF Strat-trop separation Air mass factor Combined

9 What Drives the Seasonal Variation in Tropospheric NO 2 ? τ GC τ OMI τ GC Seasonal variation in (a) NO x emissions (b) NO x lifetime Daily Average OMI time Gas phase (NO 2 + OH) Aerosol uptake of NO 2, NO 3, and N 2 O 5

10 Indirect validation of tropospheric nitrogen dioxide retrieved from the OMI satellite instrument: Insight into the seasonal variation of nitrogen oxides at northern midlatitudes, 2009, L. N. Lamsal, R. V. Martin, A. van Donkelaar, E. A. Celarier, F. K. Boersma, R. Dirksen, C. Luo, and Y. Wang, J. Geophys. Res., Submitted


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