Assessing the Lightning NO x Parameterization in GEOS-Chem with HNO 3 Columns from IASI

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Assessing the Lightning NO x Parameterization in GEOS-Chem with HNO 3 Columns from IASI Matthew Cooper 1 Randall Martin 1,2, Catherine Wespes 3, Pierre-Francois Coheur 3, Cathy

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA 3.

1 Assessing the Lightning NO x Parameterization in GEOS-Chem with HNO 3 Columns from IASI Matthew Cooper 1 Randall Martin 1,2, Catherine Wespes 3, Pierre-Francois Coheur 3, Cathy Clerbaux 3,4, Lee Murray 5 1. Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. 2. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA 3. Spectroscopie de l Atmosphère, Chimie Quantique et Photophysique, Université Libre de Bruxelles, Brussels, Belgium 4. Sorbonne Universités, UPMC Univ. Paris 06; Université Versailles St-Quentin; CNRS/INSU, LATMOS-IPSL, Paris, France 5. NASA Goddard Institute for Space Studies and Lamont-Doherty Earth Observatory of Columbia University, NY, USA

2 HNO 3 Observations Can Be Used To Constrain NO x Emission Inventories Tg OO Tg NNNN NNNN 2 HHHHHH Tg HHHH 2 OOOO 4-8 Tg CCCC

3 GEOS-Chem HNO3 Biased Low Over SE Asia molec/cm2 IASI Annual Mean Tropospheric HNO3 Column molec/cm2 GEOS-Chem Annual Mean Tropospheric HNO3 Column Percent IASI GEOS-Chem Percent Difference

4 CO Observations Can Identify Transport Of Combustion Sources Anthropogenic, Biomass burning sources emits NO x, CO Long lifetime of CO allows for evaluation of transport Lightning NO x source is independent CO

5 Regional Variations In Lightning Properties Not Captured By GEOS-Chem GEOS-Chem has 4 lightning regimes: Land Ocean Tropics Midlatitudes SE Asia lightning properties are different, which may lead to biases Simulated IC/GC Flash Ratio 0 Flash Footprint [km2] 600 Simulated IC/CG Flash Ratio Lightning Properties Observed from Space [Beirle et al., 2014]

6 The GEOS-Chem Lightning NOX Parameterization Flash rates match satellite observations Prescribed NOx/flash (260 mol/flash) Prescribed vertical profiles Emissions added to GEOS-Chem 4 x5 grid boxes

7 LNO x Plumes have Sub-Grid Spatial Scale. NO x Chemistry is Non-linear. 4 x5 GC grid box PHNO 3 (molec cm -3 s -1 ) / OPE (mol/mol) Actual Plume NO x concentration (ppbv) Early subgrid plume has high NO x concentration Leads to rapid HNO 3 production, lower OPE This is not represented in the model

8 A Simple LNOx Plume Pre-processor NOx GC Grid Box NOx HNO3 + 15O3 Current Mechanism GC Grid Box With Pre-Processing Adding 0.5 Tg N to Southeast Asia gives better agreement HNO3 Tropospheric Column (IASI Standard GEOS-Chem)/IASI (IASI GC w/ PreProcessor)/IASI 92% Bias % Bias

9 Conclusions GEOS-Chem underestimates HNO 3 in Southeast Asia Lightning NO x is most likely contributor to bias A preprocessor representing early stages of lightning plume improves the simulation

10 Bonus Slides

column = total strat Altitude (hpa) IASI Vertical Sensitivity GC Total HNO3 Column GC

11 Inferring Tropospheric Contribution to Total Column Apply IASI averaging kernel to GC output = total column Set GC troposphere to zero then apply kernel = strat column Infer tropospheric column = total strat Altitude (hpa) IASI Vertical Sensitivity GC Total HNO3 Column GC Tropospheric HNO3 Column Sensitivity Total Column Smoothed w/ IASI Kernel Tropospheric Column Smoothed w/ IASI Kernel

Can have an impact, but its small 20% change vs 200% bias

12 Convective Effects Southeast Asia/ West Pacific is highly convective region HNO3 highly soluable easily washed out Can have an impact, but its small 20% change vs 200% bias Scaled Mass Flux by 25% Scaled scavenging efficiency by 50%

Intra-cloud lightning more common in SE Asia Lightning Properties Observed by OTD/LIS [Beirle et al.

13 Some Regionally Varying Lightning Properties that could Affect SE Asia GEOS-Chem lightning scaled by observed flash density SE Asia lightning flashes are longer, more radiant than elsewhere in tropics Intra-cloud lightning more common in SE Asia Lightning Properties Observed by OTD/LIS [Beirle et al., Nat. Hazards Earth. System. Sci. Discuss, 2014] Simulated IC/GC Flash Ratio Simulated IC/CG Flash Ratio

14 Vertical Distribution of NO x Emissions NO x lifetime increases with altitude Not much change in column near emissions region Change (~30%) is small compared to the bias vs IASI (~200%) Vertical Distribution Tropospheric HNO 3 Column Ratio: Adjusted/Standard

15 LNOx Plume Pre-processor VS Prescribed Flash Yield HNO Tropospheric Column 3 (IASI Adding Tg N to Southeast Standard0.5 GEOS-Chem)/IASI agreement Asia gives better (IASI GEOS-Chem w/ Pre-Processor)/IASI Ozonesonde Standard 3.5x Nox Pre-Process

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