institut für umweltphysik (iup) amfic kick-off meeting, 26 october 2007, knmi, the netherlands...
TRANSCRIPT
Institut für Umweltphysik (iup)
AMFIC Kick-off Meeting, 26 October 2007, KNMI, The Netherlands
Carbon monoxide columns and methane column-averaged mixing ratios retrieved from SCIAMACHY
near-infrared nadir spectra
Michael Buchwitz, Oliver Schneising, Iryna Khlystova, John P. BurrowsInstitute of Environmental Physics (IUP) / Institute of Remote Sensing (IFE),
University of Bremen, Bremen, Germany
Institut für Umweltphysik (iup)
Outline
• AMFIC project: Our WPs, tasks & deliverables
• SCIAMACHY instrument
• Retrieval methode: WFM-DOAS (WFMD)
• Status carbon monoxide (CO WFMD version 0.6)
• Status methane (CH4 WFMD version 1.0)
• Available data products and formats
Institut für Umweltphysik (iup)
AMFIC project related overview I
From DoW:
WP: 2.2 „Infrared retrievals“ – Carbon monoxide and methane columns from SCIAMACHY
9/2007 K
O
9/2008
Quality assessmentAlgorithm improvementsProcessing
Final product generationDelivery
WP 3 Validation
WP: 2.2 Deliverables:D2.7: CO columns, focus 2003-2004, month 12 (9/2008)D2.8: Methane columns, focus 2003-2004, month 12 (9/2008)D2.9: Final report, month 13 (10/2008)
Institut für Umweltphysik (iup)
AMFIC project related overview II
• Status SCIAMACHY CO & methane retrieval when AMFIC proposal was written (mid 2006):
• „Only“ one year was processed, 2003 (e.g. within EU 5th FP project EVERGREEN)
• Versions: CO WFMDv0.5, CH4 WFMDv0.5 (Buchwitz et al., ACP, 2006)
• Some problems had been identified, e.g.:
• CO: Some significant biases relative to ground-based FTS (Dils et al., ACP, 2006)
• Methane: Solar zenith angle dependent bias (few percent) (Buchwitz et al., ACP, 2006)
• Proposed activities for AMFIC:
• Further studies, retrieval algorithm improvements, delivery of improved data sets (focus: 2003 & 2004)
• Current status:
• Improved data sets: CO WFMDv0.6 (Buchwitz et al., ACP, 2007), methane WFMDv1.0 (manuscript in preparation), 2003-2005
• First validation using ground-based FTS (7 European stations, 2003-2004) (Dils et al., ACVE-3, 2006)
• Ongoing & future activities: Quality assessments, assessment of usefulness for AMFIC project
Institut für Umweltphysik (iup)
SCIAMACHY on ENVISAT
SCIAMACHY Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY
Horizontal resolution:
CH4 & CO2: ~30x60km2 (0.25s)CO: ~30x120km2 (0.5s)
Institut für Umweltphysik (iup)
SCIAMACHY nadir spectrum
Wavelength [nm]
Channels 1-6
Channel 7
Channel 8
Su
n-n
orm
aliz
ed r
adia
nce
CH4
CO2
CH4CO2
CO
O2
N2O
Institut für Umweltphysik (iup)
Retrieval algorithm WFM-DOAS (“WFMD”)
Institut für Umweltphysik (iup)
Carbon monoxide from single orbit
Institut für Umweltphysik (iup)
SCIAMACHY CO: yearly average
Institut für Umweltphysik (iup)
CO WFMDv0.6: First validation using 7 European ground-based FTS
SCIA_CO_WFMDv0.6 SCIA_CO_WFMDv0.5 FTS
Dils et al., ACVE-3, 2006
SCIA-FTS 2003 2004
Bias +9.2% +0.5%
Scatter +/-20% +/-20%
Institut für Umweltphysik (iup)
SCIAMACHY CO: Comparison with MOPITT
Institut für Umweltphysik (iup)
CO & methane altitude sensitivity & CO NIR vs TIR
Averaging kernels: dVret/dV(z)true
O‘Brien, 2005
2364 nm
Coheur et al., 2005
NIR/SWIRTIR
Institut für Umweltphysik (iup)
Single ground pixel CO & CO spectral fit
Buchwitz et al., ACP, 2007
Institut für Umweltphysik (iup)
SCIAMACHY CO over China
Institut für Umweltphysik (iup)
SCIAMACHY CO2 & O2 absolute columns
-> Column-averaged dry air mole fraction XCO2 [ppm]
XCO2 := CO2column / AIRcolumn; AIRcolumn = O2column/20.95%
Similar approach for methane: XCH4 [ppb]:
XCH4 := CH4column / AIRcolumn; AIRcolumn = CO2column/370ppm
Institut für Umweltphysik (iup)
SCIAMACHY methane: Yearly average
Institut für Umweltphysik (iup)
SCIAMACHY methane 2003: Comparison with TM5
Institut für Umweltphysik (iup)
SCIAMACHY methane 2003: Comparison with TM5
JFM
AMJ
JAS
OND
SCIA CO2=const SCIA CO2=CarbonTracker TM5(S1)
Institut für Umweltphysik (iup)
SCIAMACHY methane over China
Institut für Umweltphysik (iup)
SCIAMACHY NIR channel issues
Kleipool et al., IR Phys.&Technol., 2007
SOST website:http://www.iup.uni-bremen.de/sciamachy/LTM/LTM.html
Dead & bad detector pixels Ice layer issue (channel 8)
Institut für Umweltphysik (iup)
SCIAMACHY CO & methane timeseries
Buchwitz et al., ACP, 2007
Carbon monoxide Methane
Institut für Umweltphysik (iup)
Available data products & formats
• SCIAMACHY/WFM-DOAS data products: CO cols. v0.6, XCH4 & XCO2 v1.0
• Global, 3 years (2003-2005)
• Three levels of data:
• Level 2a: Swath (= indiv. ground pixel), 1 file/orbit, QUAL=all
• Level 2b: Swath, 1 file/month, QUAL=good
• Level 3: Gridded 0.5x0.5, monthly resolution, QUAL=good• 4 files / month:
• Main product (CO column or XCH4 or XCO2)• Mean fit error• Standard deviation• Number of points / grid cell