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C. Michael Volk + the HAGAR Team With contributions by S. Viciani, A. Ulanovsky, F. Ravegnani, P. Konopka G-SPARC Workshop, Berlin, 4 December 2006 Transport Processes in the Tropical Tropopause Region Observations

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Transport Processes in the Tropical Tropopause Region Secondary TP ~345K max. conv. outflow TTL Stratospheric Subtropical barrier Troposphere Cold Point TP ~380K Subtropics latitude Isolated tropical stratosphere Goal: Diagnose transport with ozone and tracer observations Isentropic mixing across the subtropical barrier and the tropopause Mixing of overshooting air with the background TTL clear-sky heating = 0 ~360-370K

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Basic Open Question: Quantitative understanding of the balance between the dominant transport processes in the TTL as function of time and space SPARC Relevance: Key role of TTL in Climate-Chemistry Interaction (Theme 1) H2O: TTL transport details intimately linked to dehydration mechanisms Chemistry: TTL transport time scales determine abundances of short- lived and/or water soluble substances entering the stratosphere => influences stratospheric Cl, Br, I, and S budgets e.g. recent SPARC TTL sessions and workshops: Modelling of Deep Convection and of Chemistry and their Roles in the Tropical Tropopause LayerModelling of Deep Convection and of Chemistry and their Roles in the Tropical Tropopause Layer, Victoria, June 12-15, 2006 TTL session at General SPARC 3d General Assembly 2004

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Use of Tracers for tropical UTLS Transport Horizontal mixing from extratropical stratosphere (above or below tropopause): identified by stratospheric tracers: N2O, CH4, CFCs (& correlations w/ O3) Large-scale diabatic ascent: estimate using CO2, CO or O3 clock (if other processes are weak) Convective uplift: boundary layer tracers: O3 (marine), CO, CO2 (continental) Vertical mixing of overshooting air: Mixing lines in CO2, CO, O3 vs and their correlations Interhemispheric mixing in TTL (need measurements on both sides of ITCZ) tracers with large interhemispheric gradients (CO, CO2, SF6, H-1211)

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Observations by Multi-Tracer Instrument: HAGAR (High Altitude Gas Analyzer) Techniques: 2-channel-gas chromatograph LI-COR 6251 CO 2 -sensor (IR-absorption) Molecules: nom. precisionfrequency N 2 O 0.2% 90 s CH 4, F12, F11 0.5% 90 s SF 6, H 2 1.5% 90 s H-1211 2.5% 90 s CO 3% 110 s CO 2 0.1% 5-10 s

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M55 Geophysica In situ Tracer Measurements HAGAR (Univ. Frankfurt) N 2 O, F11, F12, H1211, SF 6, CO 2 (CH 4, CO, H 2 ) FOZAN (CAO, Russia): O 3 COLD (INOA, Italy): CO

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M55 Geophysica Observations in the Tropical UTLS MissionTimeRegionCharacteristics tropical flights APE-THESEO2-3/ 1999Indian Oceannon-convective7 APE-GAIA Transfer 9&10/ 1999Atlanticnon-convective4 TroCCiNOx + Transfer 1-2/2005 S Brasil Atlantic continental convection, subtropical 8484 SCOUT-O3 + Transfer 11-12/ 2005Maritime Continent maritime convection, Hector 9898 AMMA-SCOUT + Transfer 8/2006West Africacontinental convection6262 Total # of tropical flights: 48

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Horizontal mixing into tropical LS: Vertical N 2 O distribution APE-THESEO: mostly inside tropical pipe

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TROCCINOX: outside tropical pipe, mixing region Horizontal mixing into tropical LS: Vertical N 2 O distribution

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SCOUT-O3: somewhere in between Horizontal mixing into tropical LS: Vertical N 2 O distribution

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APE-THESEO: mostly inside tropical pipe Horizontal mixing into tropical LS: O 3 -N 2 O correlation

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TROCCINOX: outside tropical pipe, mixing region Horizontal mixing into tropical LS: O 3 -N 2 O correlation

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SCOUT-O3: somewhere in between Horizontal mixing into tropical LS: O 3 -N 2 O correlation

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TROC. SCOUT THESEO APE-THESEO Climatological Context of campaigns: Tropical Pipe (@ 500K) Meridional PV gradient is a measure for inhibition of isentropic mixing

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Mean tropopause TTL: Stratospheric (horizontal) inmixing during APE-THESEO ? No Evidence No significant negative O 3 -N 2 O correlation in TTL

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No low N 2 O values in TTL TTL: Stratospheric (horizontal) inmixing during SCOUT-O3 ? No significant negative O 3 -N 2 O correlation in TTL No Evidence

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TTL: Stratospheric inmixing during TROCCINOX? Significant correlations (confidence level > 99%) at > 340 K Yes, significant stratospheric influence in TTL FOZAN O3

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Slow Ascent in upper TTL and tropical lower LS => can be studied with propagation of CO2 seasonal cycle

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Slow ascent versus convection: CO and CO2 (AMMA 2006) ~15 km Highest level of convective outflow ~ 18 km ~18 km

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TroCCiNOx Convective uplift of boundary layer air into the TTL: CO2 051130b 355 K Max. outflow level ~ 355 K SCOUT-O3

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Mixing of overshooting air: CO profiles Linear mixing of CO and Vertical mixing of overshooting air in the TTL: TroCCiNOx CO

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Mixing of convected air Mixing of overshooting air in the TTL: TroCCiNOx correlations

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Mixing of overshooting air in the TTL: SCOUT-O3 ozone

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SCOUT-O3 background TTL O3 Profiles

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SCOUT-O3 background and TROCCINOX O3 profiles Elevated TTL O3 due to horizontal stratospheric inmixing

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SCOUT-O3 background and APE-THESEO O3 profiles Elevated TTL O3 due to: - Descent below Q=0 level ? - Vertical mixing ? - O3 production ?

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At the TP and above still interhemispheric gradients Interhemispheric mixing in the TTL: APE-THESEO

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ITCZ DarwinBangkok Interhemispheric mixing in the TTL: SCOUT-O3 Transfer Flights NH SH TTL

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Proposed Research for G-SPARC: Model-aided analysis of transport processes in the tropical UTLS Observations: -CO2, CO, O3, CH4, SF6, potentially other tracers from all 5 tropical M55 campaigns since 1999. -Tropical O3 profiles from the SHADOZ programme Model: Close Co-operation w/ FZ Jlich (P. Konopka) -CLaMS long-term runs with simplified chemistry for CO, CH4, O3 -CO2, CO, SF6 surface fields from NOAA CMDL global observations Goals: -Quantitative interpretation of tracer data in terms of transport processes -Validation and improvement of CLaMS transport and mixing => Quantitative understanding of transport and its impact on chemical budgets =>Determine which processes need particular attention in CCMs Approach: -Model-observation comparisons of both mean features (profiles, correlations) and specific episodes -Additional model runs to test sensitivity to mixing strength, radiative ascent -Model runs with origin of air tracers to facilitate interpretation