Ozone production in transpacific Asian pollution plumes and implications for ozone air quality in California

Transcription

1 Ozone production in transpacific Asian pollution plumes and implications for ozone air quality in California Hudman, R. C., D. J. Jacob, O. R. Cooper, M. J. Evans, C. L. Heald, R. J. Park, F. Fehsenfeld, F. Flocke, J. Holloway, G. Hubler, K. Kita, M. Koike, Y. Kondo, A. Neuman, J. Nowak, S. Oltmans, D. Parrish, J. M. Roberts, T. Ryerson PEACE-C Data Meeting November 25, 2004 This research was funded by the NOAA Office of Global Programs

2 Intercontinental Transport and Chemical Transformation (ITCT-2K2) and Pacific Exploration of Asian Continental Emissions (PEACE-B): Overview 1) PEACE-B and ITCT-2K2 aircraft campaigns: April - May N 55N 50N 45N 40N 35N 30N 50N 45N 40N 35N Cheeka Peak Trinidad Head 25N Source 30N Receptor 20N 25N 110E 115E 120E 125E 130E 135E 140E 145E 150E 140W 135W 130W 125W 120W 115W 110W 105W 100W 2) GEOS-CHEM, global 3-D model of tropospheric chemistry 3) MOPITT CO to track pollution across the Pacific Our motivation: Examine the ozone production in transpacific Asian pollution plumes, and the implications for ozone air quality in California

3 GEOS-CHEM Global 3-D Model of Atmospheric Chemistry and Transport Developed by Harvard Atmospheric Chemistry Modeling Group Used by 17 research groups in N/ America and Europe; ~100 publications driven by GEOS assimilated meteorological observations from NASA Global Modeling and Assimilation Office (GMAO); native resolution 1 o x1 o results presented today are from coupled ozone-aerosol simulation with 2 o x2.5 o resolution, 48 vertical levels Base anthropogenic emission inventory scaled to 1998 (last year of available statistics).

4 Filled Contours: Mean 0-6 km Asian FF & BB CO Line Contours: geopotential height (m) Arrows: Asian FF & BB CO Flux 0-6 km 70N 50N 30N N 50N 30N NCEP May 10N 60E 100E 140E W 100W April N 50N 30N NCEP present climatology shows zonal flow May 2002: similar to mean flow CO less due to seasonal decline May N 60E 100E 140E W 100W N 60E 100E 140E W 100W X 10-9 moles / cm 2 /s [ppbv]

5 Altitude (km) CO (ppbv) GEOS-CHEM vs. PEACE-B: Comparison along the flight tracks NOy (pptv) PAN (pptv) Modeled Slope = 2.2 R = 0.61 PAN:CO CO(ppbv) NOy:CO not correlated in model or observations LEGEND Data > 30 N Observations are averaged over model grid Observed: Solid Simulated: Dashed Red Asian FF: Dashed Green Asian BB: Dashed Blue CO: Strong BL outflow Secondary buldge above 5 km (WCB) NOy: Strong BL outflow No secondary buldge (HNO3 scavenged) Prior estimates suggest 10-15% NOx exported as NOy, of which ~50% is exported as PAN [Koike et. al, 2003; Miyazaki et al., 2003]

6 GEOS-CHEM vs. PEACE-B: Ozone underestimate partly due to straospheric intrusion underestimate Synoz [McLinden et al. 2000]: Perferred regions of downwelling underestimated O 3 (ppbv) Net Ox source of 495 Tg/yr applied Tropical upper trop Observations along flight track GEOS-CHEM Red - Comparison with Tateno (36 o N 140 o E) ozone climatology ( ) Transported by met Liu et al. [2001] found using realistic Strat Ox concentrations resulted in excessive cross tropopause flux by factor 2-3 due to noise in met fields In regions of preferred downwelling, over Japan, over NE Pacific, Stratospheric Ox concentrations will be underestimated

7 Trinidad Head, CA (daily ozonesondes April 17 - May 17): Mean ozone concentration profile during the ITCT-2K2 campaign 55N 50N 45N 40N 35N 30N 25N Cheeka Peak Trinidad Head 140W 135W 130W 125W 120W 115W 110W 105W 100W 75% of observed ozone profile showed enhancements of above 10 ppbv between 1-5 km. LEGEND Observed + /- std deviation: Black Solid Simulated: Red Dashed Strat Ox: Blue Dotted Simulated + 2X Strat Ox: Blue Dashed Doubling Stratospheric Contribution corrects discrepancy

8 Altitude (km) Trinidad Head, CA : Ozonesonde profiles on April 19 and May 7, 2002 O 3 (ppbv), Relative Humidity (%) O 3 (ppbv), Relative Humidity (%) LEGEND Observed : Black Solid Simulated: Red Dashed Strat Ox: Blue Dotted RH: Green GEOS-CHEM places stratospheric intrusions in the correct location, but underestimates by a factor of 2-3.

9 Sapporo (43N, 141E) : Ozonesonde profile on May 17, Altitude O3 (ppbv) LEGEND Observed : Red Simulated: Dashed Black Strat Ox: Dotted Blue

10 Trinidad Head, CA (daily ozonesondes April 17 - May 17): Mean ozone concentration profile during the ITCT-2K2 campaign 75% of observed ozone profile showed enhancements of above 10 ppbv between 1-5 km. LEGEND Observed + /- std deviation: Black Solid Simulated: Red Dashed Strat Ox: Blue Dotted Simulated + 2X Strat Ox: Blue Dashed Doubling Stratospheric Contribution corrects discrepancy

11 ITCT-2K2 Comparison: Comparison along the flight tracks Altitude (km) ppbv 6 pptv 200 pptv 32 ppbv 33 pptv CO(ppbv) NO (pptv) PAN (pptv) 13 ppbv HNO3 (pptv) O3 (ppbv) LEGEND Local pollution removed using NOx and aerosol filter Observations are averaged over model grid Observed: Solid Simulated: Dashed Red Asian BB & FF: Dotted Red Asian FF: Dashed Green Asian BB: Dashed Blue

12 NOAA ITCT-2K2: April-May 2002, Monterey Bay, CA Major Asian pollution plumes 55N Primarily anthropogenic Very different transport pathways 50N 45N 40N Cheeka Peak Trinidad Head MAY N Altitude (m) CO PAN 30N 25N 140W 135W 130W 125W 120W 115W 110W 105W 100W MAY 17 Altitude (m) O CO(ppbv) HNO PAN, HNO 3, NO (pptv) May 5th 5-8 km High CO, Moderate ozone enhancement High PAN May 17th 2-4 km High CO, Large Ozone enhancement PAN NOx HNO Observational Estimate: 17 ppbv ozone produced from 320 pptv PAN Ozone production efficiency per unit NOx consumed (OPE) ~50

13 70 NOAA ITCT-2K2: April-May 2002, Monterey Bay, CA Transport of May 5th plume May 4, UTC 2 X 10-9 moles/cm 2 /s MOPITT GEOS-CHEM w/ Avg Kernal Asian CO Latutude ( o N) May 6, UTC Latutude ( o N) E 100E 140E W 100W 60E 100E 140E W 100W 60E 100E 140E W 100W (column 1,2) [x10 18 molec/cm 2 ] (column 3) [ppbv]

14 NOAA ITCT-2K2: April-May 2002, Monterey Bay, CA Transport of May 17th plume 70 May 12, UTC May 14, UTC May 17, UTC Latutude ( o N) L L 10 (Asian CO) [ppbv] 70 Latutude ( o N) E 100E 140E W 100W 60E 100E 140E W 100W 60E 100E 140E W 100W (Asian Ozone) [ppbv] 2 X 10-9 moles/cm 2 /s

15 NOAA ITCT-2K2: April-May 2002, Monterey Bay, CA Major Asian pollution plumes 55N Primarily anthropogenic Very different transport pathways 50N 45N 40N Cheeka Peak Trinidad Head MAY N Altitude (m) CO PAN 30N 25N 140W 135W 130W 125W 120W 115W 110W 105W 100W MAY 17 Altitude (m) O CO(ppbv) HNO PAN, HNO 3, NO (pptv) May 5th 5-8 km High CO, Moderate ozone enhancement High PAN May 17th 2-4 km High CO, Large Ozone enhancement PAN NOx HNO Observational Estimate: 17 ppbv ozone produced from 320 pptv PAN Ozone production efficiency per unit NOx consumed (OPE) ~50

16 PAN driven ozone production in subsiding transpacific pollution plumes Stratospheric downwelling Warm Conveyor Belt 10-15% NOx exported as NOy OPE ~5 PAN PAN, moderate ozone enhancement Subsidence PAN NOx HNO3 OPE ~60-80 strong ozone enh. into dry region with strong insolation NOx HNO3 Asia U.S.

17 Surface Ozone at Trinidad Head, CA: April - May 2002 Timeseries [Goldstein et al., 2004] Neither model nor observations show much variability Asian enhancement in GEOS-CHEM (6 +/- 2) significant, but undetectable

18 California mountain sites are particularly sensitive to Asian Ozone pollution: Observed 8-h ozone at Sequoia National Park (1800 m) in May 2002 vs. corresponding simulated (GEOS-CHEM) Asian pollution ozone enhancement. May 17 obs. Asian plume event in red Observed ozone (ppbv) 8-hr running mean Asian enhancements are 6-10 ppbv during NAAQS exceedances; unlike at surface sites, Asian pollution influence is not minimum under high-ozone conditions! Simulated Asian Ozone Enhancement (ppbv) 8-hr running mean