C. Michael Volk + the HAGAR Team With contributions by S. Viciani, A. Ulanovsky, F. Ravegnani, P....
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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
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
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
Slide 2
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
Slide 3
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
Slide 4
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)
Slide 5
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
Slide 6
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
Slide 7
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
Slide 8
Horizontal mixing into tropical LS: Vertical N 2 O distribution
APE-THESEO: mostly inside tropical pipe
Slide 9
TROCCINOX: outside tropical pipe, mixing region Horizontal
mixing into tropical LS: Vertical N 2 O distribution
Slide 10
SCOUT-O3: somewhere in between Horizontal mixing into tropical
LS: Vertical N 2 O distribution
Slide 11
APE-THESEO: mostly inside tropical pipe Horizontal mixing into
tropical LS: O 3 -N 2 O correlation
Slide 12
TROCCINOX: outside tropical pipe, mixing region Horizontal
mixing into tropical LS: O 3 -N 2 O correlation
Slide 13
SCOUT-O3: somewhere in between Horizontal mixing into tropical
LS: O 3 -N 2 O correlation
Slide 14
TROC. SCOUT THESEO APE-THESEO Climatological Context of
campaigns: Tropical Pipe (@ 500K) Meridional PV gradient is a
measure for inhibition of isentropic mixing
Slide 15
Mean tropopause TTL: Stratospheric (horizontal) inmixing during
APE-THESEO ? No Evidence No significant negative O 3 -N 2 O
correlation in TTL
Slide 16
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
Slide 17
TTL: Stratospheric inmixing during TROCCINOX? Significant
correlations (confidence level > 99%) at > 340 K Yes,
significant stratospheric influence in TTL FOZAN O3
Slide 18
Slow Ascent in upper TTL and tropical lower LS => can be
studied with propagation of CO2 seasonal cycle
Slide 19
Slow ascent versus convection: CO and CO2 (AMMA 2006) ~15 km
Highest level of convective outflow ~ 18 km ~18 km
Slide 20
TroCCiNOx Convective uplift of boundary layer air into the TTL:
CO2 051130b 355 K Max. outflow level ~ 355 K SCOUT-O3
Slide 21
Mixing of overshooting air: CO profiles Linear mixing of CO and
Vertical mixing of overshooting air in the TTL: TroCCiNOx CO
Slide 22
Mixing of convected air Mixing of overshooting air in the TTL:
TroCCiNOx correlations
Slide 23
Mixing of overshooting air in the TTL: SCOUT-O3 ozone
Slide 24
Slide 25
SCOUT-O3 background TTL O3 Profiles
Slide 26
SCOUT-O3 background and TROCCINOX O3 profiles Elevated TTL O3
due to horizontal stratospheric inmixing
Slide 27
SCOUT-O3 background and APE-THESEO O3 profiles Elevated TTL O3
due to: - Descent below Q=0 level ? - Vertical mixing ? - O3
production ?
Slide 28
At the TP and above still interhemispheric gradients
Interhemispheric mixing in the TTL: APE-THESEO
Slide 29
ITCZ DarwinBangkok Interhemispheric mixing in the TTL: SCOUT-O3
Transfer Flights NH SH TTL
Slide 30
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