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C ivil A ircraft for R egular I nvestigation of the atmosphere B ased on an I nstrument C ontainer. C A R I B I C. Luftfrachtcontainer gefüllt mit wissenschaftlichen Instrumenten, eingebaut für einzelne Messflüge 1 – 2 Messflüge pro Monat (24 – 48 Flugstunden)
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Civil Aircraft for Regular Investigation of the atmosphere Based on an Instrument Container C A R I B I C • 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
PTR-MS O3 H2O CARIBIC II Container
>4nm 18-180nm CARIBIC II maiden flight 13/14 Dec 2004 Frankfurt - Buenos Aires
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
Mess-Zelle (p,T const.) Laser Sample Detektor Referenz Detektor Reiner Absorber Referenz-Zelle ([c] const.) Tunable Diode Laser Absorption Spectroscopy (TDLAS)zur Messung von D/H, 17O/16O und 18O/16O in H2O Christoph Dyroff Lambert-Beer σ(ν) Absorptionsquerschnitt N Molekül Konzentration L Absorptionlänge Aufeinander abgestimmt
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. What we can learn from isotope measurements in the atmosphere? d - notation e.g. d18O(H2O) = (Rsample / RV-SMOW – 1) * 1000 o/oo with R = 18O/16O
Isotope fractionation processes • Phase transitions e.g. vapour pressure isotope effect • Chemical reactions • Kinetic fractionation diffusion, transport • Photolysis rates • (Radioactive decay)
isotope ratio trace gas hydrogenD/H (T/H) H2O, CH4, H2 carbon13C/12C (14C/12C) CO2, CH4, CO (C2H6, C3H8, …) oxygen17O/16O,18O/16O H2O, CO2, CO, N2O, O3 (NO2, …) nitrogen15N/14N N2O (NH3, NH4, NO2, NO3, …) (10Be/7Be, 34S/32S) Isotopes measured in the atmosphere Standard Mean Ocean Water (SMOW) D/H 155.76 · 10-6 17O/16O 379.9 18O/16O 2005.2 PeeDee Belemnite (PDB)13C/12C 11180 17O/16O 385.9 18O/16O 2067.2 Air (AIR)15N/14N 3676.5
solar radiation meteorites, asteriodes, comets ablation + evaporation Isotope fractionation effects CHEMICAL REACTIONS stratosphere PHOTOLYSIS Tropopause 8 – 16 km gas-particle transformation condensation + evaporation stratospheric tropospheric Exchange (STE) free troposphere CHEMICAL REACTIONS sedimentation + rainout boundary layer 1 – 2 km terrestrial radiation volcanism condensation + sublimation biosphere mankind dissolution condensation evaporation effusion + deposition sedimentation ices
CO2 O(1D) H H2O O OH HNO3 H2O „Transfer“ of isotope anomaly SO42- S(IV)aq NMHC O3 CO NO NO2 at ground O3 N2O NO3
MIF dHDO = - (600-800)o/oo dH218O = - (100-160)o/oo DH217O = 0o/oo(= d17O – 0.52 * d18O) ice lofting MDF kinetic fractionation vapor pressure isotope effect Processes controlling H2O isotopomers 30 km T R A N S P O R T + C H E M I S T R Y CH4 oxidation H2O HOx,, Ox 23 km 17 km 8 km T R A N S P O R T
Isotope fractionation of H2O a = 1 – e a fractionation factor e fractionation Raleigh fractionation dRcondensate = a(T) · Rgas Rgas(t) = Rgas(0)·fa-1 vapour pressure istope effect (vpie) avpie kinetic fractionation akin = S(T) / [avpie· D/Di ·(S(T)-1) + 1] S(T) oversaturation
H2O isotope observations at ground Meteoric Water Line (MWL) (in precipitation) dD(H2O) = 8.0 ·d18O(H2O) + 8.6 (in per mil)
IAEA / WMO networkfor H2O isotope composition in monthly precipitation
H2O isotope observations at ground Meteoric Water Line (MWL) (in precipitation) dD(H2O) = 8.0 ·d18O(H2O) + 8.6 (in per mil) Temperature effect dD(H2O) = 8.0 ·d18O(H2O) + 8.6 (in per mil)
H2O isotope observations airborne sampling at 50-80°N, DI-IRMS measurement in the laboratory Zahn, 2001
Kuang et al., GRL, 2003 Webster et al., Science, Dec. 2003 H2O isotope observations
Origin of O of freshly produced OH O isotopism of OH controls dO(H2O) ! > 99 % of all H2O molecules produced in the middle atmosphere are due to H abstraction by OH: CH4 + OHH2O + CH3 CH2O + OHH2O + HCO HCl + OHH2O + Cl OH + OHH2O + O(3P) H2 + OHH2O + H What reactions form new OH bonds ? X + O2HOx + Y X + O3HOx + Y X + O(1D) HOx + Y O exchange: OHx + O2, NO, H2O