1 C A R I B I C Civil Aircraft for Regular Investigation of the atmosphere Based on an Instrument Container  Luftfrachtcontainer gefüllt mit wissenschaftlichen Instrumenten, eingebaut für einzelne Messflüge  1 – 2 Messflüge pro Monat (24 – 48 Flugstunden)  11 beteiligte europäische Institute (Koordination: MPI-C, Mainz) MPI für Chemie, Mainz IMK, Karlsruhe IFT, Leipzig DLR, Oberpfaffenhofen GKSS, Geesthacht Universität Heidelberg UEA, Norwich, UK University Lund, Sweden KNMI, de Bilt, The Netherlands CEA/CNRS, Paris, France Universität Bern, Schweiz

2 CARIBIC II

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7 CARIBIC II Container PTR-MSO3O3 H2OH2O

8 >4nm nm CARIBIC II maiden flight 13/14 Dec 2004 Frankfurt - Buenos Aires

9 CARIBIC II: Status & Zukunft Status  Anfang Dezember 2004: Fluggenehmigung Airbus A340 & Container durch LBA  13/14. Dezember: Erstflug nach Buenos Aires/Santiago  Logistik vollständig (high-loader, LKW, test equipment etc.)  Einlass funktioniert mechanisch & elektrisch  Airbus „power management“ erlaubt noch keine Aufwärmphase vor Flug  (kleine) Softwareprobleme bei Master PC  einige Instrumente noch nicht vollständig funktionsbereit Zukunft  Zweitflug: 18/19. Februar 2005 nach Sao Paulo/Santiago (Parallelflug TROCCINOX)  Danach 1-2 Messflüge (25-60 h) pro Monat  anvisierte Flugziele: Südamerika, Südafrika, Ost Asien, Ostküste Nordamerika  2005: beheben aller technischer Probleme, keine neuen Geräte  Veröffentlichungen & Anträge schreiben

10 Tunable Diode Laser Absorption Spectroscopy (TDLAS) zur Messung von D/H, 17 O/ 16 O und 18 O/ 16 O in H 2 O Lambert-Beer σ( ν ) Absorptionsquerschnitt NMolekül Konzentration LAbsorptionlänge Laser Mess-Zelle (p,T const.) Referenz-Zelle ([c] const.) Sample Detektor Reiner Absorber Referenz Detektor Aufeinander abgestimmt Christoph Dyroff

11 Erste Messspektren bei 1.37μm, L~40 cm 0.10 nm

12 What we can learn from isotope measurements in the atmosphere? central motivation of atmospheric isotope studies is to better understand the budget of the examined trace constituents, i.e. to quantify source/sink strenghts, chemical processing, photolysis rates, transport fluxes etc.  - notation e.g.  18 O(H 2 O) = (R sample / R V-SMOW – 1) * 1000 o / oo with R = 18 O/ 16 O

13 Isotope fractionation processes  Phase transitions e.g. vapour pressure isotope effect  Chemical reactions  Kinetic fractionation diffusion, transport  Photolysis rates  (Radioactive decay)

14 Isotopes measured in the atmosphere Standard Mean Ocean Water (SMOW) D/H · O/ 16 O O/ 16 O PeeDee Belemnite (PDB) 13 C/ 12 C O/ 16 O O/ 16 O Air (AIR) 15 N/ 14 N isotope ratiotrace gas hydrogen D/H (T/H)H 2 O, CH 4, H 2 carbon 13 C/ 12 C ( 14 C/ 12 C)CO 2, CH 4, CO (C 2 H 6, C 3 H 8, …) oxygen 17 O/ 16 O, 18 O/ 16 OH 2 O, CO 2, CO, N 2 O, O 3 (NO 2, …) nitrogen 15 N/ 14 NN 2 O (NH 3, NH 4, NO 2, NO 3, …) ( 10 Be/ 7 Be, 34 S/ 32 S)

15 Isotope fractionation effects solar radiation CHEMICAL REACTIONS condensation + sublimation stratospheric tropospheric Exchange (STE) effusion + deposition biospheremankind ablation + evaporation meteorites, asteriodes, comets Tropopause 8 – 16 km CHEMICAL REACTIONS volcanism sedimentation dissolution condensation evaporation gas-particle transformation condensation + evaporation sedimentation + rainout ices terrestrial radiation boundary layer 1 – 2 km free troposphere stratosphere PHOTOLYSIS

16  17 O –  18 O plot

17 O 3 formation: rate coefficient ratios

18 „Transfer“ of isotope anomaly O3O3 SO 4 2- S(IV) aq N2ON2O CO NMHC NO NO 2 at ground NO 3 O3O3 O( 1 D) CO 2 OH H2OH2O HNO 3 H2OH2O H O

19 O-transfer O 3 CO 2 in the stratosphere O 3 + h (  < 320 nm)  O( 1 D) + O 2 O( 1 D) + CO 2  CO 3 *  O( 3 P) + CO 2 Boering et al., 2004 MDF, slope: troposphere

20 Processes controlling H 2 O isotopomers vapor pressure isotope effect kinetic fractionation ice lofting T R A N S P O R T + C H E M I S T R Y MIF MDF CH 4 oxidation H 2 O  HO x,, O x  HDO = - ( ) o / oo  H 2 18 O = - ( ) o / oo  H 2 17 O = 0 o / oo (=  17 O – 0.52 *  18 O) 17 km 8 km 23 km 30 km

21 Isotope fractionation of H 2 O  = 1 –  fractionation factor   fractionation Raleigh fractionation dR condensate =  (T) · R gas  R gas (t) = R gas (0)·f  -1 vapour pressure istope effect (vpie)  vpie kinetic fractionation  kin = S(T) / [  vpie · D/D i ·(S(T)-1) + 1] S(T) oversaturation

22 H 2 O isotope observations at ground Meteoric Water Line (MWL) (in precipitation)  D(H 2 O) = 8.0 ·  18 O(H 2 O) + 8.6(in per mil)

23 IAEA / WMO network for H 2 O isotope composition in monthly precipitation

24 Local MWL in water vapour at Heidelberg

25 H 2 O isotope observations at ground Meteoric Water Line (MWL) (in precipitation)  D(H 2 O) = 8.0 ·  18 O(H 2 O) + 8.6(in per mil) Temperature effect  D(H 2 O) = 8.0 ·  18 O(H 2 O) + 8.6(in per mil)

26  18 O(H 2 O) vs. T in water vapour at Heidelberg

27 H 2 O isotope observations Zahn, 2001 airborne sampling at 50-80°N, DI-IRMS measurement in the laboratory

28 H 2 O isotope observations Webster et al., Science, Dec Kuang et al., GRL, 2003

Simulated Isotope Profiles

O isotopism of OH controls dO(H 2 O) ! > 99 % of all H 2 O molecules produced in the middle atmosphere are due to H abstraction by OH: CH 4 + OH  H 2 O + CH 3 CH 2 O + OH  H 2 O + HCO HCl + OH  H 2 O + Cl OH + OH  H 2 O + O( 3 P) H 2 + OH  H 2 O + H What reactions form new OH bonds ? X + O 2  HO x + Y X + O 3  HO x + Y X + O( 1 D)  HO x + Y O exchange:OH x + O 2, NO, H 2 O Origin of O of freshly produced OH