Slide 1

Organic trace gases in the extratropical UTLS during START08E. Atlas, R. Lueb, X. Zhu, L. Pope (UM)F. Moore, D. Hurst, J. Elkins, R. Gao (NOAA)L. Pan, S. Tilmes, B. Hall, B. Stephens, A. Weinheimer, F. Flocke, I. Pollack, W. Zheng, D. Knapp, T. Campos, S. Schauffler, R. Hendershot (NCAR)S. Wofsy, B. Daube, R. Jimenez, S. Park, E. Kort (Harvard)K. Bowman, C. Homeyer (TAMU)Acknowledgements: Funding by National Science Foundation; Support of pilots, staff, and management of NCAR Research Aviation Facility.A large suite of trace gases were measured during START08OzoneWater vaporCarbon MonoxideCarbon DioxideNitrous OxideMethaneReactive Odd Nitrogen (NOY) /Nitric OxideOrganic trace gases:Whole Air Sampler (AWAS)In-situ GC/ECD and GC/MS (PANTHER/UCATS)with a variety of interesting propertiesHydrocarbons, halocarbons, sulfur and nitrogen containing VOC (>50 gases)Greenhouse gasesDifferent source emission characteristicsMid latitude pollution/Biogenic emission and uptake/Biomass burningGradients with latitude/altitudeDifferent chemical lifetimesKnown temporal trends in the atmosphere (e.g. HCFCs, HFCs, CO2,SF6) Scientific objectivesTracer correlationsMixing scales for gases of different lifetimes/loss processesCharacterization of trace gas compositions for different mixing regimes/source regionsUse of tracers to estimate age spectra Age of air relationshipsSources of reactive halogen (Br) to the LSExamination of specific casesTropospheric intrusions/RF01 + RF14

Ozone: CO correlations

RF03: ExtratropicalUTLS SurveyRF04: Stratospheric IntrusionRF01: TroposphericIntrusionOzone:tracer correlations

CH3CCl3~ 5 yr.CHCl3~ 0.5 yrC2Cl4~.25 yrC3H8~.06 yr

Local photochemical lifetimes (days) of VSL halocarbons in the UT/LS From WMO Ozone Assessment, Chapter 2, Ko and PouletSample coverage (relative to tropopause): ~ 35% of samples within 2 km of trop.

CH2Cl2:O3 correlation STARTo8

Mixing pathways and tracer correlation Sub tropical Jet

TropicsPoleHigh theta branchStratospheric Intrusion(Tropopause fold)Low theta branchTroposphereStratosphereTropopause

Gravity wave generation and breakingMixing on top of the STJLong range transportConvective transportBased on figure by Randel and Pan, SPARC Newsletter no.22Processes coupling dynamics, chemistry and cloud microphysics in the UTLS regionProcesses affecting extratropical UT/LS: Tropics to pole

Ozone: CH2Cl2 (binned by O3:Q)CH2Cl2: O3 START08 & TC4

Ethane: O3 START08 & TC4

Case Study: RF01 tropospheric intrusionEvaluate trace gas signature of high-theta, low ozone air mass observed at 14 km, near 50 N latitude:Stratospheric age-of-air tracersSF6, CO2Comparison to HCFC, HFC trendsExamination of shorter-lifetime, reactive gasesComparison to potential source region

START08: RF01

Tropospheric intrusion: RF01

Tropospheric tracersCompoundLifetimeTrend /year (global NOAA)Mixing ratio (std. dev) in tropospheric intrusionSulfur Hexafluoride>600 yr.3 ppt/yr (5 %)6.3 (.03) pptvCarbon Dioxide-~ 2 ppm/yr (0.5%)384.7 (.2) ppmvHCFC 141b9.3 yr0.6 ppt/yr (3%)18.4 (0.1) pptvHCFC 142b17.9 yr1.0 ppt/yr (5%)17.1* (0.3) pptvHCFC 2212.0 yr7.4 ppt/yr (4%)184 (1) pptvHFC 134a14.0 yr4.3 ppt/yr (9%)44.2 (1.0) pptvEthane~100 day-376 (23) pptvPropane~ 20 day-14 (5) pptvEthyne~ 35 day-52 (3) pptvn-Butane~ 10 day-3.1 (0.4) pptvDibromomethane~120 day-0.87 (0.01) pptvBromoform~ 26 day-0.15 (.02) pptvIsopropyl nitrate~ 8 day-0.35 (.04) pptv

DATA FROM NOAA ESRLSF6 atmospheric trendJan. mid Feb.CO2 : Atmospheric trend

mid to late February

HFC-134a : Atmospheric TrendAug.-Sept.,2007HFC-134a (pptv)Vertical distributions: HCFCs

90%

93%Vertical distributions: HCFCs

93%92%

HFC-134a : Atmospheric TrendFeb. - MarchTropical tropopause estimate = 97% Global Surface AverageAge of air: corrections for altitude gradient CompoundAge based on Global Mean SurfaceBased on trop =95% surface96 % surface97% surface98% surfaceHCFC 22August, 2007April May, 2008Feb-March,2008HCFC 141bNov. Dec., 2006May June,2008Feb. April,2008Oct. Nov.,2007HCFC 142bJune - July,2007April May,2008Jan. Feb.,2008Oct. Dec.,2007HFC 134aAug. Sept., 2007April May, 2008March April,2008Feb March, 2008Shorter lived trace gases:CompoundRF01 Intrusion LayerTTL (Costa Rica, January)Ethane376 23323 55Propane14 517 16Ethyne52 335 10n-Butane3.1 0.44.1 6.7Isopropyl nitrate0.35 .04.08 .25Dibromomethane0.87 .010.57 .20Bromoform0.15 .020.10 0.15Carbon Monoxide51 253 5Ozone158 1386 22Ozone:q correlation

RF01, RF08, RF14, RF17START08: RF14

RF14: Flight curtain (d/dz)

START08: RF17

RF17: Flight curtain (d/dz)

RF01: Flight curtain (d/dz)

Shorter lived trace gases:CompoundRF01 Intrusion LayerRF14 Intrusion LayerRF17 UT/near tropopauseTTL (Costa Rica, January)Ethane376 23374 15375 37323 55Propane14 516 219 917 16Ethyne52 337 342 635 10n-Butane3.1 0.43.0 0.82.8 2.74.1 6.7Isopropyl nitrate0.35 .040.20 .080.37 .12.08 .25Dibromomethane0.87 .010.75 .020.74 .060.57 .20Bromoform0.15 .020.10 .020.16 .090.10 0.15Carbon Monoxide51 247 151 453 5Carbon Dioxide384.7 0.2386.1 0.2386.6 0.8Ozone158 13162 15200 4486 22Air mass back trajectories: RF14(19:37 20:57 Z & >13 km)

Air mass back trajectories: RF17(23:10 00:13 Z)

SummaryComprehensive suite of trace gases with range of source region/reactivity were measured during START08.Case study of tropospheric intrusion:Different trace gases consistent with meteorological analysis of source/timing.Age of air in intrusion about 2 3 monthsShort-lived tracers (days to months) present at levels similar to TTL and UT (tropical origin).

Ozone: age correlation from SF6Tracer : O3 correlationsLow theta

Troposphere (max)Stratosphere (min)

Tracer : O3 correlationsHigh thetaTroposphere (max)Stratosphere (min)