Download M. Reuter, EMS, Berlin, September 2011

M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
M.Reuter , O.Schneising , M.Buchwitz , J.Heymann, H.Bovensmann, J.P.Burrows
Institute of Environmental Physics, University of Bremen, Germany
EMS, Berlin, September 2011
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
ESA’s GHG-CCI: Aims and Motivation
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
ESA’s GHG-CCI: Road Map
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Two in-house algorithms
BESD (XCO2)
WFMD (XCO2, XCH4)
Inversion Algorithm:
Optimal Estimation;
Full Physics
Least-squares;
Light path Proxy
A-priori constraints:
Yes
Constant: CO2(p), aerosol,
cirrus, ...
Per pixel: P, T, H2O, ...
No
(constant atmosphere as
linearization point for RT)
ECMWF
US Standard (sev. H2O)
State vector (APS)
Constant; AAI filter (CO2 only)
State vector (CWP, CTH);
Filtering: MERIS 1x1 km2
RT cloud free;
Filtering: O2 & PMD (CO2 only)
Merged fit windows
Independent fit windows
SCIATRAN on-line
SCIATRAN LUT
Slow (~15 min./pixel)
Fast (~2 min./orbit)
Accuracy
Compromise accuracy/speed
Atmosphere:
Aerosols:
Clouds:
Fit windows:
Radiative Transfer:
Speed:
Optimized for:
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
BESD XCO2
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Validation with TCCON FTS measurements
Park Falls, USA
350km
Bremen, Germany
350km
Darwin, Australia
350km
Lauder, New Zealand
350km
• Restriction to a limited validation data set due to computational costs
• Only 4 TCCON sites measured in the full period 2006-2010
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Comparison with FTS, CarbonTracker, GOSAT
Overall good agreement between
SCIAMACHY, GOSAT, FTS
and CarbonTracker
No statistical significant
regional biases
Single measurement
precision ~2.5ppm
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Comparison with FTS, CarbonTracker, GOSAT
Smoothed Results show:
Good agreement of year-to-year increase and seasonal amplitude.
(Data density allows smoothing only at Park Falls and Darwin)
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
WFMD XCO2
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
Global increase
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Computational costs are orders of magnitude lower
Processing of global data easily possible
A global dataset 2003-2009 is available
Similar annual global patterns
Continuous year-to-year increase of global XCO2
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
CO2 uptake by growing vegetation
Mean wind direction
Fnet
Assumption:
XCO2 gradient in wind direction
approximately proportional
to net surface flux Fnet
XCO2
West
Longitude
East
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
CO2 uptake by growing vegetation
Calculation of gradients above
boreal forests (Canada+Russia):
Good agreement with CarbonTracker
(year-to-year progression and size)
Canada: larger neg. gradients
suggest stronger CO2 uptake
Russia: less strong gradients
suggest weaker CO2 uptake
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
http://www.esa-ghg-cci.org/
Intercomparison with other XCO2 algorithms
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Within the GHG CCI several different XCO2 retrieval
techniques are involved: BESD, WFMD, and the algorithms of
SRON, University of Leicester, ACOS, and NIES
First inter-comparisons with FTS measurements show many
similarities but also differences which have to be analyzed
M. Reuter, EMS, Berlin, September 2011
Retrieval of atmospheric CO2 from satellite near-infrared
nadir spectra in the frame of ESA’s climate change initiative
http://www.esa-ghg-cci.org/