ICDC7, Boulder, 26-30 September 2005 CH 4 TOTAL COLUMNS FROM SCIAMACHY – COMPARISON WITH ATMOSPHERIC MODELS P. Bergamaschi 1 , C. Frankenberg 2 , J.F. Meirink 3 , M. Krol 1 , F. Dentener 1 , M. van Weele 3 ,T. Wagner 2 , U. Platt 2 , S. Koerner 4 , M. Heimann 4 , 1 European Commission Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy 2 Institute for Environmental Physics, University of Heidelberg, Heidelberg, Germany 3 Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands 4 Max Planck Institute for Biogeochemistry, Jena, Germany
Transcript
ICDC7, Boulder, 26-30 September 2005
CH4 TOTAL COLUMNS FROM SCIAMACHY –
COMPARISON WITH ATMOSPHERIC MODELS
P. Bergamaschi1, C. Frankenberg2, J.F. Meirink3, M. Krol1, F. Dentener1, M. van Weele3,T. Wagner2, U. Platt2, S. Koerner4, M. Heimann4,
1European Commission Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy2Institute for Environmental Physics, University of Heidelberg, Heidelberg, Germany3Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands4Max Planck Institute for Biogeochemistry, Jena, Germany
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SCIAMACHY
absorption spectra of solar radiation (near-IR)
-> high sensitivity also towards the surface
Main challenge:
Target precision / accuray ~ 1%
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SCIAMACHY - validation
ground based FTIR (total column measurements)
NDSC network
- very few stations (~11) only; no coverage of tropical source regions
- FTIR precision (~3%), accuracy (~7%) [Dils et al., 2005]
comparison with other satellites
currently no other CH4 retrievals available
(except some exploratory retrievals from IMG/ADEOS (1997)
inverse modelling
using high precision / accuracy surface insitu / flask measurements (CH4 ~ 0.1%)
-> global 3D CH4 fields
alternative approach:
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model - validation
validation of models (and bottom-up emission inventories)
in particular over source regions which are not well sampled by the surface measurements
Final objective:
Better quantification of CH4 emissions
opposite view:
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TM5 model
TM5 model – atmospheric zoom model
• offline atmospheric transport model
• meteo from ECMWF
• global simulation 3o x 2o
• zooming 1o x 1o (North America, South America, Europe, Africa, Asia, Australia)
• http://www.phys.uu.nl/~tm5/
• [Krol et al., 2005]
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TM5 simulationsinversion based on groundbased monitoring sites
synthesis inversion optimizing:
- monthly emissions
- 11 source categories
- 7 global regions for wetlands
- 5 global regions for biomass burning
ground based background monitoring sites (NOAA/CMDL)
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TM5 inverse simulationsexamples for some monitoring sites
simulation of global CH4 consistent with surface monitoring sites (background sites)
01 Jan 31 Dec
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SCIAMACHY vs. TM5 - global
2003 average
column averaged CH4 [ppb]
TM5
SCIA
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SCIAMACHY vs. TM5 - global
2003 average
column averaged CH4 [ppb]
TM5
SCIA
N-S gradient ~100 ppb
consistent between SCIA and TM5
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SCIAMACHY vs. TM5 - global
2003 average
column averaged CH4 [ppb]
TM5
SCIA
Enhanced CH4 over SouthEast Asia and tropical regions (S.America, Africa)
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SCIAMACHY vs. TM5 - Asia 04-06 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - Asia 07-09 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - Asia 10-12 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - South America 01-03 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - South America 04-06 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - South America 07-09 2003
TM5
SCIA
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SCIAMACHY vs. TM5 - South America 10-12 2003
TM5
SCIA
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South America 01-03 2003 JK
CH4 emission from wetlands: J. Kaplan [2005]
spatial distribution of wetlands based on GLC2000
TM5
SCIA
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South America 01-03 2003 BW
CH4 emission from wetlands: Walter et al. [2001]
spatial distribution of wetlands based on [Matthews and Fung, 1987]
TM5
SCIA
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SCIAMACHY vs. TM5: global std, bias
std
bias
daily SCIA retrievals vs. TM5 (global over land)
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Conclusions
• SCIAMACHY provides view on global CH4 distribution
• Enhanced CH4 over SouthEast Asia, and tropical regions of South America and Africa (CH4 up to ~70 ppb)
• Comparison with inverse simulations, optimized towards insitu observations:
• Background regions: reference for validation of SCIAMACHY retrievals
• Source regions: Different model scenarios yield significantly different CH4 distributions -> rather check of consistency than strict validation
• potential (seasonal) bias (in particular over Australia (~20 ppb))
• average N-S gradient (~100 ppb) consistent between SCIAMACHY and TM5
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Thank you !
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Supporting Material
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SCIAMACHY / ENVISAT
SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY)
SCIAMACHY on ENVISAT
altitude: 800 km
14 orbits per day
full global coverage: every 6 days
CH4: 1563-1585 nm
CO2: 1631-1670 nm
(O2: 760 nm)
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SCIAMACHY VCD->VMR
variability of total columns:
CO2 ~ 1/3 CH4
Conversion
vertical column densities (V) [molec / cm2]
-> column averaged mixing ratios (VMR) [ppb]
use of CO2 instead of O2 for determination of total vertical column of dry air [Frankenberg et al., Science, 2005]
-> very similar light path distribution (scattering)
CO2 VMR from TM3
column averaged CH4 mixing ratio [ppb]
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SCIAMACHY - averaging kernels
[Frankenberg et al., 2005]
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SCIAMACHY vs. TM5 - global (incl. ocean)
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emission inventories for TM5 simulations
coal IIASA / EDGAR V3.2oil and gas IIASA / EDGAR V3.2enteric fermentation IIASA / EDGAR V3.2rice GISS [Matthews et al., 1991]biomass burning [van der Werf et al., 2004]waste IIASA / EDGAR V3.2wetlands [Kaplan, 2005]
[Walter et al., 2000]wild animals GISS [Fung et al., 1991]termites GISS [Fung et al., 1991]ocean [Houweling et al., 1999]soil sink GISS [Fung et al., 1991]
bottom-up emission inventories used as priori emissions for inverse TM5 simulations:
