Institut für Umweltphysik (iup) AMFIC Kick-off Meeting, 26 October 2007, KNMI, The Netherlands Carbon monoxide columns and methane column- averaged mixing

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


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


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)


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


SCIAMACHY on ENVISAT

SCIAMACHY Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY

Horizontal resolution:

CH4 & CO2: ~30x60km2 (0.25s)CO: ~30x120km2 (0.5s)


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


Retrieval algorithm WFM-DOAS (“WFMD”)


Carbon monoxide from single orbit


SCIAMACHY CO: yearly average


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%


SCIAMACHY CO: Comparison with MOPITT


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


Single ground pixel CO & CO spectral fit

Buchwitz et al., ACP, 2007


SCIAMACHY CO over China


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


SCIAMACHY methane: Yearly average


SCIAMACHY methane 2003: Comparison with TM5


SCIAMACHY methane 2003: Comparison with TM5

JFM

AMJ

JAS

OND

SCIA CO2=const SCIA CO2=CarbonTracker TM5(S1)


SCIAMACHY methane over China


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)


SCIAMACHY CO & methane timeseries

Buchwitz et al., ACP, 2007

Carbon monoxide Methane


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

Documents

Institut für Umweltphysik (iup) AMFIC Kick-off Meeting, 26 October 2007, KNMI, The Netherlands Carbon monoxide columns and methane column- averaged mixing