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Insights into Urban Pollution from Ozone Soundings: Beltsville (MD), Houston and IONS (INTEX Ozonesonde Network Study, 2004 & 2006). Anne M Thompson, PSU Meteo IONS Data Partners: S J Oltmans (NOAA), E Joseph (HU); B Rappenglueck, G Morris (UH)
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Insights into Urban Pollution from Ozone Soundings: Beltsville (MD), Houston and IONS (INTEX Ozonesonde Network Study, 2004 & 2006) Anne M Thompson, PSU Meteo IONS Data Partners: S J Oltmans (NOAA), E Joseph (HU); B Rappenglueck, G Morris (UH) Analysis:RAs & Students S K Miller, J E Yorks, K M Dougherty, J W-C Hui, A M Luzik, D C Doughty, G G Garner; Postdoc – Brett Taubman
Road Map • IONS Networks – 2004, 2006 (http://croc.gsfc.nasa.gov) • “Strategic,” campaign oriented, 3-6 wk daily launches • Scientific Question – Beltsville ozone budgets, LID method • Global model: MOZART – LID budget comparisons • Regional AQ Forecasting • CMAQ evaluation -- Empirical (sonde) alternative
“Strategic Ozonesonde Network:” IONS (2004) Design Strategy • Design (INTEX Ozonesonde Network Study = IONS; INTEX = Intercontinental Transport Expt - NA) to answer: • Can O3 be followed during INTEX? Similar to “Match” • TROPOSPHERIC BUDGETS: How much Asian pollution reaches NA? How much O3 from stratosphere-troposphere exchange (ST), advection (AD), lightning (RCL), local boundary-layer (BL) pollution? • Can O3 pollution be measured from satellite? Predicted? July-Aug 04. 290 sondes. http://croc.gsfc.nasa.gov/intex/ions.html
LID = Laminar Identification (Thompson et al., 2007). For Each Sonde, Combine O3-Pot. Temp Layer ID with Tracers, eg Satellite Fires, PV for Stratosphere
Results – 2005-2007 Beltsville: Free-Tropospheric O3 • Column integrated ozone units (1 DU = 2.69 x 1016cm-2) • 2005 - Most polluted of 3 summers; mean free-tropospheric ozone, 45 DU • 2006 – Relatively unpolluted. Note > 30 DU of ozone had stratospheric signatures on 16 July. • 2007 – Lower amount in July, more polluted in August. (Yorks et al, 2008)
Beltsville MD (WDC suburbs) – Summer FT Statistics (2004-07) – Persistent ST Influence • Left - Distribution of Free Tropospheric O3 percent due to ST (blue) skewed higher than regional convection/lightning (Yorks et al, 2008) • Right – Typical summer sounding with ozone “pollution” appearance but stratospheric origins.
Global Model Results. G. G. Pfister et al., JGR, in press • Use MOZART CTM (coupled chemical-transport model) with “labeled” NO(x) sources to determine ozone sources • Period is IONS-04 – July-mid-August 2004 • Budget for ozone is full troposphere, averaged over lower 48 US • “Typical model result” – hardest to capture • Individual laminae • Stratospheric amount • BL, partly due to sampling in large grid
Fig 8 – Pfister et al. Average model contribution (tropospheric ozone column) of MOZART sources – leftbar. Shaded, right bars - LID budget. Averages over IONS-04, 1 July-15 Aug 2004. Results – Remarkably good agreement, on average.MOZART differentiates sources that LID budget cannot, eg fires, Asian vs US pollution (“US” = lower 48). NOTE! Color scales not the same.
IONS-06 for INTEX-B/ Milagro/ Aura (Phase 1, 2) & TEXAQS (Phase 3) • Strategy - Daily Sondes in three 4-week Campaigns. Phase 3: • August 2006 – TEXAQS-06 What is upwind-downwind of Texas? • <croc.gsfc.nasa.gov/intexb/ions06> Reference: A. M. Thompson et al., Atmos. Chem. Phys. 8, 5113-5125, 2008.
CMAQ & IONS-06: IONS-06 Network (upper). Three of six LBC tested (lower). From Tang et al., EFM, 2008 • IONS-06 Network, • Thompson et al., ACP, 2008
CMAQ Result: Individual IONS-06 Comparisons with Six LBCs 3 Aug 06. Pollution aloft, BV, HSV; surface not very polluted From Tang et al., EFM, 2008 • > Free tropospheric ozone improved with IONS LBC. • > Surface AQF not accurate, esp at Beltsville. • Surface AQF not very LBC-sensitive • Mixing issue with model? • Chemical reaction set limitations?
Beltsville (suburban WDC) Surface Ozone and Sonde Statistics, Based on June-Aug 2005-2007 Data • Define a “residual layer” with equiv PT inflections. Distinct from Surface Layer – RL can be “local” or transported ozone • Two distinct sets of RL profiles emerge (center, right) • Consider an Alternative Empirical Air Quality Forecast • Compare nighttime sonde data with surface ozone data • Assumption: mixing from residual layer above (RL – yesterday’s ozone, maybe from upwind!) critical to surface ozone evolution • Does high ozone RL predict high surface ozone better than a model? • J E Yorks, MS Thesis, 12/07; Yorks et al: Atmos. Environ., submitted, 2008
“Empirical Ozone Forecast” Distinct high-RL (red) and lower-RL ozone (green) profiles from set of 22 nighttime balloon sondes over Beltsville, summers 2005-2007. Corresponding surface ozone at Beltsville, averaged over 1-hr maximum period (center) and 8-hour maximum period (right). With NAAQS 8-hr 80 ppbv standard, the high RL (red) in right-hand case calls for Code Orange Alert. From Yorks et al, 2008; Update by G Garner
Sonde Evaluation of NAQFS Forecast – For days with nighttime sondes, classified by RL and whether or not a low-level jet, mixing RL ozone to SL • Persistent over-prediction in all cases • O3 avg. observed below NAAQS threshold, avg. forecast above threshold • Only in one case did surface ozone actually exceed threshold
Summary – Three Results • “IONS Strategic Ozonesonde Networks” provide unique data for: • Global & regional model initialization, evaluation • Independent, empirically-based ozone budgets – LID method • Model Comparisons show Good Progress – • MOZART guided to better tropopause & STE ozone treatment (Pfister et al., 2008) • Initialization, evaluation in ‘classic’ AQF model is promising! (Tang et al, 2008) • Night-Day sondes: Powerful “alternative” AQ Forecast, at least for moderately polluted region like WDC (Yorks, Thesis; on-going with G Garner for 2009 publication). Note that these AQF are tailored to region! • Way Forward – • More data analysis for AQF approaches. PSU students to complete BV-NAQFS comparisons • Work with CMAS Community to design “smart” sonde strategies in future. Target, optimize key sites • Model-sonde comparisons at Beltsville also using (1) CO, VOC, NOx data (2006); (2) varying chemical mechanisms in NSF project with W. R. Stockwell, Howard Univ.
THANK YOU FOR YOUR ATTENTION!Acknowledgments, References • Aura Validation; NASA Tropospheric Chemistry Program for INTEX-B • References • G G Pfister et al., Analysis of the summer 2004 ozone budget over North America using IONS observations and MOZART-4 simulations, JGR, 2008 (Papers in Press on AGU website) • Y. Tang et al., The impact of chemical lateral boundary conditions on CMAQ predictions of tropospheric ozone over the continental United States, Environ. Fluid Mech., DOI 10.1007/s10652-008-9092-5, 2008. • A. M. Thompson, et al., IONS (INTEX Ozonesonde Network Study, 2004). 1. Summertime UT/LS (Upper Troposphere/Lower Stratosphere) Ozone over Northeastern North America, J. Geophys. Res., 112, D12S12, doi: 10.1029/2006JD007441, 2007a. • A. M. Thompson, et al., IONS (INTEX Ozonesonde Network Study, 2004): 2. Tropospheric Ozone Budgets and Variability over Northeastern North America, J. Geophys. Res., 112, D12S13, doi: 10.1029/2006JD007670, 2007b. • A. M. Thompson et al., Tropospheric Ozone Sources and Wave Activity over Mexico City and Houston during Milagro/Intercontinental Transport Experiment (INTEX-B) Ozonesonde Network Study, 2006 (IONS-06), Atmos. Chem. Phys. 8, 5113-5125, 2008. • J. E. Yorks et al, A. M. Thompson, E. Joseph, S. K. Miller, The variability of free tropospheric ozone over Beltsville, Maryland (39N, 77W) in the summers 2004-2007, Atmos. Environ., submitted, 2008.
