OMI ST meeting 11 20-22 June 2006 Calibration & 0-1b data processing Marcel Dobber (KNMI)

OMI calibrationCalibration
0-1b data processing
Marcel Dobber (KNMI)
OMI ST Meeting 11, 20-22 June 2006 Slide * Marcel Dobber, KNMI
Contents
Conclusions.
Calibration team
Glen Jaross (SSAI / NASA)
Ruud Dirksen (KNMI / SRON), will leave calibration team per 1 July 2006 to work on NO2 with Henk Eskes
Werner Dierssen (KNMI / TriopSys), left per 1 May 2006
Johan de Vries (DS), left per 1 January 2006
Irradiance
31 DEC 2004
Irradiance
These radiometric keydata were still exclusively based on on-ground measurements.
31 DEC 2004
Irradiance
In these radiometric keydata corrections obtained from in-flight comparisons have been used.
Status CCD detectors: Pixels with permanently increased dark current as function of time
6 February 2006 (571 days after launch)
UV: 17.0% of all unbinned pixels (image area)
VIS: 17.6% of all unbinned pixels (image area)
Chart1
36
36
58
58
75
75
101
101
125
125
133
133
139
139
158
158
205
205
316
316
501
501
571
571
Percentage of (unbinned) pixels with permanently increased DC
UV (blue) and VIS (red) detector pixels with permanently increased dark current
0.0077993311
0.007451505
0.0124370123
0.0123455964
0.0152151616
0.0152173913
0.0237369008
0.0240958751
0.0309186176
0.0312753623
0.0363166109
0.0367848384
0.0385507246
0.0386510591
0.0408428094
0.0406867336
0.0568940914
0.0577458194
0.0909966555
0.0909386845
0.1476544036
0.1496120401
0.1695362319
0.1756209588
Blad1
Date
Number of pixels with permanently increased DC
Blad2
UV
UV detector pixels with permanently increased dark current
Blad3
Percentage of (unbinned) pixels with permanently increased DC
Days since launch
Days since launch
UV (blue) and VIS (red) (unbinned) CCD detector hot pixels
GDPS status (1)
v0.9.12 (26 August 2005), not used in ps0002:
Same version as 0.9.13, but with a bug: the flagged transient pixels were not excluded in the calculation of the irradiance average.
v0.9.13 (31 August 2005):
New DEM saturation flagging algorithm.
New transient pixel flagging algorithm replaces old one.
Fixed bug in calculation global products from spatial zoom-in products.
GDPS status (2)
New algorithm for irradiance goniometry (dIRRAD) replaces the old one.
See TN-OMIE-KNMI-754, issue 3, 1 February 2006.
Wavelength dependence is now also dependent on azimuth and elevation angles and row.
Maximum 2nd order polynomial for wavelength dependence.
Row dependence not fitted, but stored per row in OPF.
Wavelength dependence not per subchannel.
Possibility to bypass the dIRRAD algorithm in the algorithm bypass list.
Intended LUT change (LED linearity measurements).
v0.9.15 (3 March 2006), not used in ps0002. See also v0.9.14:
LUT change (LED linearity measurements) was not updated. v0.9.14 was never used, but immediately replaced by v0.9.15.
GDPS status (3)
v0.9.16 (7 June 2006, TBC):
New algorithm for USA / LSA stray light correction replaces the old one.
See TN-OMIE-KNMI-792, issue 2, 30 March 2006.
See TN-OMIE-KNMI-814, issue 1, 30 May 2006.
Predefined shapes as function of column in OPF for LSA and USA for earth, sun, WLS.
Row dependence with linear interpolation between LSA and USA.
New algorithm for spectral stray light correction replaces old one.
See TN-OMIE-KNMI-802, issue 1, 27 March 2006.
Row dependence with preset (OPF) windows for stray light source and target regions.
Changes to OPF’s
New entries for DEM saturation flagging algorithm.
Added spectral slit function parameterisation data.
Changed OPF cross-sections used for spectral calibration.
Changed (slightly) spectral calibration parameters.
Changed radiometric keydata without changing BSDF.
Changed fallback dark images.
Changed dark current temperature correction parameters.
Changes to OPF’s
OPF 31 (GDPS 0.9.15)
New entries for new irradiance goniometry algorithm (see TN-OMIE-KNMI-818, issue 1, 18 April 2006).
OPF ?? (GDPS 0.9.16)
New entries for spectral stray light algorithm.
Updated radiometric calibration keydata.
Updated swath angle dependent radiometric keydata
BSDF swath angle dependence will not be changed
New dark image data.
Possibly new BDPM (RTS, see TN-OMIE-KNMI-791, issue 1, 30 January 2006).
Possibly new non-linearity.
Reprocessing in ps0002
Reprocessing end 2006
Required for reprocessing end 2006, as far as calibration is concerned (i.e. list may not be complete!):
GDPS 0.9.16, delivered 19-23 June 2006.
OPF for GDPS 0.9.16 (see one of previous slides).
TDOPF software + system.
Integrated TMCF PGE’s (see next slide).
Stray light parameters will be optimised as good as possible, but further changes in the future can not be excluded.
Time-dependent functions will be set constant in TDOPF, except for:
Background images.
BDPM (which includes RTS).
TMCF and TMCF PGE’s
TMCF and ODPS very stable:
upgrade operating system.
new storage facility.
TMCF PGE’s:
Automated Analysis PGE (basic analyses).
Dark signal median calculation (this one will be used for the reprocessing of end 2006).
Irradiance azimuth and elevation angle dependence.
TMCF and TMCF PGE’s
TMCF PGE’s (continued):
Dark current.
False-RGB image calculation.
False-RGB image visualisation.
Quality Flag summary.
Colours:
PGE integrated in TMCF and running
PGE integrated in TMCF and running, but a new version is ready for integration.
PGE ready and waiting for integration in TMCF.
Background images used in reprocessing
The OPF background images will be updated with a frequency of once per day using a median calculation algorithm.
Once per day is a compromise between:
Large vs smaller data amounts for TDOPF system.
Number of background images available to reduce measurement noise sufficiently.
Per earth ICID 5+5 images per orbit, provided no passage through SAA, for sun measurements 77 images per orbit.
Per earth ICID (5+5)*14=140 images per day (minus SAA), for sun measurements 77 images per day.
Once per week is not sufficient, given the rate at which the CCD is hit by high-energetic protons.
Median to exclude pixels with large deviations.
Plan for OPF for GDPS 0.9.16
Optimise LSA / USA and spectral stray light parameters.
Adapt radiometric calibration parameters.
L1 and L2 to provide feedback.
After this GDPS 0.9.16 + OPF are ready for reprocessing.
Future plans
Stripes in L1 and L2 data after reprocessing: situation will be considerably better.
Continue to monitor potential optical degradation behaviour using WLS and solar spectra.
Continue to monitor CCD detector degradation behaviour.
Further optimise convoluted high-resolution solar reference spectrum w.r.t. measured solar irradiance.
Continue validation Earth reflectances (including swath angle dependence), BSDF structures, BSDF interchannel jumps (especially after stray light changes).
Conclusions
Calibration data gap March-May 2006 due to FMM anomaly investigation.
Stray light parameters must be optimised, plans for this are in place.
Working towards reprocessing end 2006:
GDPS 0.9.16 + OPF.
TMCF + PGE’s.
Recent documents
Ozone Monitoring Instrument Calibration, IEEE Transactions on Geoscience and Remote Sensing, vol. 44, no. 5, May 2006, 1209-1238.
Prelaunch characterization of the Ozone Monitoring Instrument transfer function in the spectral domain, Applied Optics, vol. 45, no. 17, 10 June 2006, 3972-3981.
Method of calibration to correct for cloud-induced wavelength shifts in the Aura satellite’s Ozone Monitoring Instrument, Applied Optics, vol. 45, no. 15, 20 May 2006, 3652-3658.
UV part
5 cm
increased dark current
permanently increased DC

OMI ST meeting 11 20-22 June 2006 Calibration & 0-1b data processing Marcel Dobber (KNMI)

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Transcript of OMI ST meeting 11 20-22 June 2006 Calibration & 0-1b data processing Marcel Dobber (KNMI)