1 C A R I B I C Civil Aircraft for Regular Investigation of the atmosphere Based on an Instrument...
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Transcript of 1 C A R I B I C Civil Aircraft for Regular Investigation of the atmosphere Based on an Instrument...
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C A R I B I CCivil 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
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CARIBIC II
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4
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CARIBIC II ContainerPTR-MS O3 H2O
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>4nm18-180nm
CARIBIC II maiden flight 13/14 Dec 2004Frankfurt - Buenos Aires
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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
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Tunable Diode Laser Absorption Spectroscopy (TDLAS)
zur Messung von D/H, 17O/16O und 18O/16O in H2O
Lambert-Beer
σ(ν)
Absorptionsquerschnitt
N Molekül
Konzentration
L Absorptionlänge
Laser Mess-Zelle (p,T const.)
Referenz-Zelle ([c] const.)
Sample Detektor
Reiner Absorber
Referenz Detektor
)(
)0(10)()0()( log)exp(
ll I
IODlNII
Aufeinander abgestimmt
Christoph Dyroff
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Erste Messspektren bei 1.37μm, L~40 cm
0.10 nm
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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.18O(H2O) = (Rsample / RV-SMOW – 1) * 1000 o/oo
with R = 18O/16O
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Isotope fractionation
processes
Phase transitions
e.g. vapour pressure isotope effect
Chemical reactions
Kinetic fractionation
diffusion, transport
Photolysis rates
(Radioactive decay)
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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 1118017O/16O 385.918O/16O 2067.2
Air (AIR) 15N/14N 3676.5
isotope ratio trace gas
hydrogen D/H (T/H) H2O, CH4, H2
carbon 13C/12C (14C/12C) CO2, CH4, CO (C2H6, C3H8, …)
oxygen 17O/16O, 18O/16O H2O, CO2, CO, N2O, O3 (NO2, …)
nitrogen 15N/14N N2O (NH3, NH4, NO2, NO3, …)
(10Be/7Be, 34S/32S)
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Isotope fractionation effects
solar radiation
CHEMICALREACTIONS
condensation+
sublimation
stratospherictroposphericExchange
(STE)
effusion+
deposition
biosphere mankind
ablation+
evaporation
meteorites,asteriodes,
comets
Tropopause
8 – 16 km
CHEMICALREACTIONS
volcanism
sedimentation
dissolutioncondensationevaporation
gas-particletransformation
condensation+
evaporation
sedimentation + rainout
ices
terrestrialradiation
boundary layer
1 – 2 km
free
troposphere
stratosphere
PHOTOLYSIS
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17O – 18O plot
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O3 formation: rate coefficient ratios
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„Transfer“ of isotope anomaly
O3
SO42-
S(IV)aq
N2O
CONMHC
NO
NO2
at ground
NO3
O3
O(1D) CO2
OH
H2O
HNO3
H2O
H
O
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Processes controlling H2O isotopomers
vapor pressureisotope effect
kineticfractionation
ice lofting
T R A N S P O R T
T R A N S P O R T + C H E M I S T R Y
MIF
MDF
CH4 oxidation
H2O HOx,, Ox
HDO = - (600-800)o/oo
H218O = - (100-160)o/oo
H217O = 0o/oo (= 17O – 0.52 * 18O)
17 km
8 km
23 km
30 km
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Isotope fractionation of H2O
= 1 – fractionation factorfractionation
Raleigh fractionation
dRcondensate = (T) · Rgas Rgas(t) = Rgas(0)·f-1
vapour pressure istope effect (vpie)
vpie
kinetic fractionation
kin = S(T) / [vpie · D/Di ·(S(T)-1) + 1] S(T)
oversaturation
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H2O isotope observations at ground
Meteoric Water Line (MWL) (in precipitation)
D(H2O) = 8.0 · 18O(H2O) + 8.6 (in per mil)
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IAEA / WMO networkfor H2O isotope composition in monthly
precipitation
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Dec
Nov
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
-170
-160
-150
-140
-130
-120
-110
-23 -22 -21 -20 -19 -18 -17 -16 -15
18O [‰]
D [
‰]
D = 7.81 18O + 8.3
slope = 7.75
Local MWL in
water vapour
at
Heidelberg
1981-2000
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H2O isotope observations at ground
Meteoric Water Line (MWL) (in precipitation)
D(H2O) = 8.0 · 18O(H2O) + 8.6 (in per mil)
Temperature effect
D(H2O) = 8.0 · 18O(H2O) + 8.6 (in per mil)
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18O(H2O) vs. T in water vapour at Heidelberg
1981-2000
18O = 0.43 T - 23.22
18O = 0,80 T - 24,39
18O = 0,39 T - 23,03
-30
-25
-20
-15
-10
-10 0 10 20 30
T [°C]
O
[‰
]
-30
-25
-20
-15
-10
winter
summer
spring & autumn
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H2O isotope observations
Zahn, 2001
airborne sampling at 50-80°N, DI-IRMS measurement in the laboratory
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H2O isotope observations
Webster et al., Science, Dec. 2003
Kuang et al., GRL, 2003
Simulated Isotope Profiles
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 + OH H2O + CH3
CH2O + OH H2O + HCO
HCl + OH H2O + Cl
OH + OH H2O + O(3P)
H2 + OH H2O + H
What reactions form new OH bonds ?
X + O2 HOx + Y
X + O3 HOx + Y
X + O(1D) HOx + Y
O exchange: OHx + O2, NO, H2O
Origin of O of freshly produced OH