[email protected] Spectral shapes modeling and remote sensing of greenhouse gases....
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[email protected]Spectral shapes modeling and remote sensing of greenhouse gases. Toward the OCO and GOSAT experiments and future HITRAN issues Jean-Michel HARTMANN L.I.S.A. (CNRS and Université Paris VII and Paris XII) Créteil, FRANCE and Geoffrey TOON (JPL), Ha TRAN (LISA) but also hristian BOULET, Linda BROWN, André BUTZ, Christian FRANKENBERG, Robert GAMACHE, Frank HASE, J. LAMOUROUX, Ann LARIA,, …
[email protected] Spectral shapes modeling and remote sensing of greenhouse gases. Toward the OCO and GOSAT experiments and future HITRAN issues
[email protected] Spectral shapes modeling and
remote sensing of greenhouse gases. Toward the OCO and GOSAT
experiments and future HITRAN issues Jean-Michel HARTMANN L.I.S.A.
(CNRS and Universit Paris VII and Paris XII) Crteil, FRANCE and
Geoffrey TOON (JPL), Ha TRAN (LISA) but also Christian BOULET,
Linda BROWN, Andr BUTZ, Christian FRANKENBERG, Robert GAMACHE,
Frank HASE, J. LAMOUROUX, Ann LARIA,,
Slide 2
Monitoring GreenHouse Gases from space Nadir looking
instruments onbord sattelites Orbiting Carbon Observatory (OCO,
NASA, launch failed but OCO2 coming) Greenhouse gases Observation
SATellite (GOSAT, JAXA-NIES, in orbit) MiniCarb (CNES, under study)
Spectral regions and aims. - CO 2 from 1.6 m (weak) and 2.1 m
(strong) bands - Air mass from O 2 A band (near 762 nm - CH4 from 2
3 band (near 1.7 m) - aerosols from CO 2 and O 2 bands
Detection/quantifying sinks and source Extreme accuracy of spectra
modelings (0.3 %). Huge constraints on the spectroscopic data and
the prediction of pressure effects (collisions and spectral-shape
New issues for HITRAN database
Slide 3
Spectral shapes and HITRAN Basic Isolated line shape: Voigt
Convolution of Lorentz (collisions) and Gaussian (Doppler). HITRAN
provides almost all needed data (except T dep of shift and self
broad, broadening by H 2 O) Refined Isolated line shape: speed
dependence and Dicke narrowing Effects of the speed dependences of
collisional width and shift and of velocity changes. HITRAN does
not provide any data.
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Collisionally coupled Lines: Line-mixing, no SD nor Dicke Modeled
through the relaxation matrix W whose size is N C xN C where N C is
the number of coupled lines (block diagonal with respect to bands)
HITRAN does not provide any data. Speed dependent Dicke narrowed
Line-mixing profiles: Very complex problem, still to be studied in
laboratories
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Collision Induced Absorption (CIA) Electric dipole moment induced
during collisions. Weak and broad absorption features. HITRAN does
not provide any data
Slide 4
CO 2 : Ground-based atmospheric solar absorption 2.1 m band
Spectra: Sza 79.9, Park Falls Wrong time and air-mass dependences
Largely erroneous conclusions on sinks and sources (huge source at
poles, huge sink at mid-latitudes
Slide 5
CO2 1.6 micron band
Slide 6
O 2 : Ground-based atmospheric solar absorption A-band Spectra:
Sza 79.9, Park Falls Wrong time and airmass dependences Large
errors on air masses or pressure vertical profiles for high North
and South latitudes
Slide 7
O2 1.27 micron band
Slide 8
CH 4 : Ground-based atmospheric solar absorption 2 3 band
Spectra: air mass 5.7, Park Falls Wrong time and airmass
dependences Largely erroneous conclusions on sinks and sources
Slide 9
Spectroscopic data: isolated lines Voigt profiles (no SD, no
Dicke) CO2 bands: Toth essentially identical to HITRAN2008 except
for widths O2 A-band: HITRAN2008 (Brown, Robichaud, others) CH4 2 3
: a mixture of Frankenberg, Nikitin and Pine What we have used
(state of the art ?) Line mixing data: off-diagonal W matrix
elements CO 2 bands: Niro et al (2005). Self consistent model for
all bands No use NB: Adjustment of model in 720 cm -1 Q branch. No
use of present NIR bands O 2 A-band: Tran et al (2008). Model
developed from O 2 A band at elevated pressure. No use NB: No use
of low pressure spectra CH 4 : Tran et al (2006). Self consistent
model for 3, 4 and 2 3 bands) NB: Adjustment of model in 3 band at
high pressure. No use of present NIR band Collision Induced
Absorption O 2 A-band: Tran et al (2008). From analysis of O 2 A
band at elevated pressure. No use NB: No use of low pressure
spectra
Slide 10
Validation of LM model using laboratory spectra: O 2 and CO 2
76.0 atm 47.6 atm 28.1 atm ___ measurement, ___ LM ___ Lorentz O2 A
bandCO2 band
Slide 11
Validation of LM model using laboratory spectra: CH 4 2 3 band
With effective line-broadening and shifting and with Voigt
profiles: Frankenberg et al., ACP, 2008 (and HITRAN 2008) With true
line-broadening and shifting coeffs. and with LM (black), Voigt
(red)
Slide 12
Consequences for atmospheric spectra: O 2 A band case Spectra:
Sza 79.9, Park Falls Significantly reduced residuals but some
structures remain
Slide 13
O 2 A band: Relative errors on surface pressures retrieved from
atmospheric spectra
Slide 14
Consequences for atmospheric spectra: CO 2 2.1 m region
Spectra: Sza 79.9, Park Falls Significantly reduced residuals but
some structures remain
Slide 15
Scaling factor, applied to the a priori CO 2 vmr profile,
retrieved from fits Inclusion of LM reduces air mass dependence and
inconsistency between Results from weak and strong CO 2 band. But
still slight air mass dependence for large air masses
Slide 16
Consequences for atmospheric spectra: The CH 4 2 3 case
Slide 17
Methane amounts (ratio of the total CH 4 column to the total
air column) retrieved from atmospheric spectra
Slide 18
Getting closer to OCO/GOSAT needed accuracy Accounting for LM
in CH 4 (2 3 ), CO 2 (2.1 m) and O 2 (A-band) and for CIA in O 2
necessary. When done, transmission fits residuals between -0.01 and
+0.01. Small but still above noise level and showing systematic and
structured features. Still insufficient HITRAN 2008 may not be the
best Need for a very careful and critical inter-comparison of
available isolated line data CO2: Toth et al, Predoi-Cross et al,
Benner et al, . O2: Brown et al, Predoi-Cross et al, Robichaud et
al, Hodges et al, . CH4: Frankenberg et al, Nikitin et al, Lyulin
et al, Wang et al, Analysis of CH4 lab measurements by including LM
to be done Lab recordings of 2 m CO2 band and analysis with LM
needed Need for a very careful and critical intercomparison of
Line-Mixing CO2: Tran et al, Predoi-Cross et al, Benner et al O2:
Tran et al, Filippov et al Need for a very careful and critical
intercomparison of CIA O2: Tran et al, van der Zande et al Need to
study SD and Dicke effects: Theoretical work need, influence on
atmospheric transmissions to be done
Slide 19
Future HITRAN issues Updates Include results of intercomparison
and new measurements for isolated line parameters. New features:
-Include line shift T dependence (some results available) - Include
self broadening T dependence for O 2 (some results available) -
Include broadening by H 2 O and T dep (some results available for
CO 2 lines, no negligible effect in remote sensing) - Include LM:
must be done on the side since different structure. Store
relaxation files and related spectroscopic data. Eventually provide
software (eg: Lamouroux et al, Tran et al) NB: needs to kind of
standardization -Speed dependence and Dicke effects: What is to be
stored ? Not obvious, thinking necessary. Theoretical work starting
at LISA