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Destriping of Viirs Modis Sst v2
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Transcript of Destriping of Viirs Modis Sst v2
Destriping of VIIRS and MODIS SST imageryDestriping of VIIRS and MODIS SST imagery
Marouan Bouali and Alexander IgnatovMarouan Bouali and Alexander Ignatov
NOAA/NESDIS/STAR and CSU/CIRANOAA/NESDIS/STAR and CSU/CIRA
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Workshop: “SST from polar orbiters: use of NWP models” Workshop: “SST from polar orbiters: use of NWP models” Centre de Météorologie Spatiale, Météo FranceCentre de Météorologie Spatiale, Météo France,, Lannion Lannion
March 5-7, 2013March 5-7, 2013
3/4/2013 Destriping VIIRS/MODIS SST
MotivationMotivationNative resolution SST imagery (≤1km) derived from whiskbroom Native resolution SST imagery (≤1km) derived from whiskbroom
scanners (MODIS, VIIRS) is affected with stripe noisescanners (MODIS, VIIRS) is affected with stripe noise
2Sea Surface Temperatures (°C)Sea Surface Temperatures (°C)
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
Terra MODISTerra MODIS Aqua MODISAqua MODIS NPP VIIRSNPP VIIRS
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T2012294110000.L2_LAC_SSTT2012294110000.L2_LAC_SST A2012294031500.L2_LAC_SSTA2012294031500.L2_LAC_SST ACSPO_V2.12_NPP_VIIRS_2012-10-20_1510-1519ACSPO_V2.12_NPP_VIIRS_2012-10-20_1510-1519
Accuracy of SST retrievalAccuracy of SST retrieval
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NPP VIIRS (0.75 km)NPP VIIRS (0.75 km)
Stripe noise in level 1B or SDRs BTsStripe noise in level 1B or SDRs BTscan lead to SST errors of up to ± 0.3Kcan lead to SST errors of up to ± 0.3K
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
ACSPO_V2.12_NPP_VIIRS_2012-10-20_1510-1519ACSPO_V2.12_NPP_VIIRS_2012-10-20_1510-1519
SST FrontsSST Fronts
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NPP VIIRS (0.75 km)NPP VIIRS (0.75 km)
Sobel filterSobel filter
Striping introduces artificial structures and affects the analysis of Striping introduces artificial structures and affects the analysis of thermal fronts (orientation, intensity and location)thermal fronts (orientation, intensity and location)
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
ACSPO_V2.12_NPP_VIIRS_2012-10-20_1840-1849ACSPO_V2.12_NPP_VIIRS_2012-10-20_1840-1849
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Prior to assimilating into UHR L4 SST,Prior to assimilating into UHR L4 SST,MODIS and VIIRS L2 SSTs should be destripedMODIS and VIIRS L2 SSTs should be destriped
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
UHR L4 SST will be increasingly used as input in NWP modelsUHR L4 SST will be increasingly used as input in NWP modelsdue to better weather prediction (LaCasse et al. 2008)due to better weather prediction (LaCasse et al. 2008)
ESA MEDSPIRATIONESA MEDSPIRATION
NASA JPL MURNASA JPL MURNASA JPL G1SSTNASA JPL G1SST
Ultra-High Resolution Level 4 SSTsUltra-High Resolution Level 4 SSTs
3/4/2013
Mitigation of stripingMitigation of striping
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Currently, blackbody (BB) and space view (SV) are used for Currently, blackbody (BB) and space view (SV) are used for absolute BT calibration on a scan-by-scan basisabsolute BT calibration on a scan-by-scan basis
This practice ensures that sensor uniformity performance is This practice ensures that sensor uniformity performance is within pre-launch specification within pre-launch specification BUTBUT it does not guarantee full it does not guarantee full mitigation of striping effectmitigation of striping effect
Post-processing of L1B (SDR) is required to generate improved Post-processing of L1B (SDR) is required to generate improved L1B, from which SST products with improved image quality can L1B, from which SST products with improved image quality can be producedbe produced
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
Destriping LiteratureDestriping Literature
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~ 40 years of research (since Landsat MSS, 1972)~ 40 years of research (since Landsat MSS, 1972)
Techniques with potential for operational use are intended for Techniques with potential for operational use are intended for highly pronounced stripe noise whereas,highly pronounced stripe noise whereas,
Stripe noise in 11 & 12 µm bands (MODIS, VIIRS) is below 0.05 K..Stripe noise in 11 & 12 µm bands (MODIS, VIIRS) is below 0.05 K..
No work has been done so far for stripe noise reduction in SST No work has been done so far for stripe noise reduction in SST imagery other than…imagery other than…
Spatial smoothing of the atmospheric term in SST algorithmSpatial smoothing of the atmospheric term in SST algorithm
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
SST = aSST = a00 . BT . BT1111+ a+ a11. BT. BT1212 + a + a22.SST.SSTrefref.[(BT.[(BT1111-BT-BT1212))**HH](sec(Ɵ) -1)](sec(Ɵ) -1)
Low signal-to-stripe noise ratio (SSNR)Low signal-to-stripe noise ratio (SSNR)
Low-pass filterLow-pass filter
3/4/2013
Towards Operational Destriping Towards Operational Destriping
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RequirementsRequirements
Automatic:Automatic: Minimize supervision and algorithm tuning Minimize supervision and algorithm tuning
Robust:Robust: Maximize improvement of image quality, i.e., minimize: Maximize improvement of image quality, i.e., minimize: Residual stripesResidual stripes DistortionDistortion Processing artifactsProcessing artifacts
Fast:Fast: Suitable for real-time processing of satellite data. Suitable for real-time processing of satellite data.
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
Adaptive DestripingAdaptive Destriping
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Scene-based denoising algorithm based onScene-based denoising algorithm based on
Directional Hierarchical Decomposition (DHD) using on a Directional Hierarchical Decomposition (DHD) using on a unidirectional quadratic variational modelunidirectional quadratic variational model
Nonlocal filteringNonlocal filtering
““Adaptive Reduction of Striping for Improved SST Imagery from S-NPP VIIRS”, Adaptive Reduction of Striping for Improved SST Imagery from S-NPP VIIRS”, JTech, 2013 (in review)JTech, 2013 (in review)
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
Adaptive DestripingAdaptive Destriping
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Directional Hierarchical DecompositionDirectional Hierarchical Decomposition
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
Observed image (f)Observed image (f)
Horizontal gradientHorizontal gradient Vertical gradientVertical gradient
11stst guess “True Image” (u guess “True Image” (u00)) 11stst guess noise (v guess noise (v00))
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== ++
Adaptive DestripingAdaptive Destriping
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
uu00 f-vf-v11
vv00 vv11 vv22 vv33 vv44 vv55 vv66
f, Noisy imagef, Noisy image
f-vf-v22 f-vf-v33 f-vf-v44 f-vf-v55 f-vf-v66
3/4/2013
Iteration #1Iteration #1 #2#2 #3#3 #4#4 #5#5 #6#6
Preliminary Results: DataPreliminary Results: Data
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Data: 3 days of level 1B/SDR TOA calibrated BTsData: 3 days of level 1B/SDR TOA calibrated BTs- Terra MODIS Terra MODIS - Aqua MODISAqua MODIS- NPP VIIRSNPP VIIRS
Destriping algorithm applied to SST bands @ 3.7, 11 and 12µmDestriping algorithm applied to SST bands @ 3.7, 11 and 12µm
Destriped BTs used as input in ACSPO prior to cloud masking and Destriped BTs used as input in ACSPO prior to cloud masking and SST productionSST production
Cloud mask and SST image quality compared with/without Cloud mask and SST image quality compared with/without destripingdestriping
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-27_1910-1919 (from original SDRs)
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-27_1910-1919 (from destriped SDRs)
SST Fronts (0.75 km)SST Fronts (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-27_1910-1919 (from original SDRs)3/4/2013
SST Fronts (0.75 km)SST Fronts (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-27_1910-1919 (from destriped SDRs)3/4/2013
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-24_0300-0309 (from original SDRs)3/4/2013
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-24_0300-0309 (from destriped SDRs)
SST Fronts (0.75 km)SST Fronts (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-24_0300-0309 (from original SDRs)3/4/2013
SST Fronts (0.75 km)SST Fronts (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-24_0300-0309 (from destriped SDRs)
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from original SDRs)3/4/2013
SST image quality (0.75 km) SST image quality (0.75 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from destriped SDRs)
SST image quality (4 km) SST image quality (4 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from original SDRs)3/4/2013
SST image quality (4 km) SST image quality (4 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from destriped SDRs)
SST Fronts (4 km)SST Fronts (4 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from original SDRs)3/4/2013
SST Fronts (4 km)SST Fronts (4 km)
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-21_0740-0749 (from destriped SDRs)
Impact on cloud maskImpact on cloud mask
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
ACSPO_V2.12_NPP_VIIRS_2013-01-31_0600-0609 (from original SDRs)3/4/2013
Impact on cloud maskImpact on cloud mask
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013ACSPO_V2.12_NPP_VIIRS_2013-01-31_0600-0609 (from destriped SDRs)
Destriping performanceDestriping performance
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The Normalized Improvement Factor (NIF)The Normalized Improvement Factor (NIF)quantifies the improvement in image qualityquantifies the improvement in image quality
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
Monitoring of the NIF index over a 3 day period indicatesMonitoring of the NIF index over a 3 day period indicatesstable destriping performance (5% ≤ NIF stable destriping performance (5% ≤ NIF ≤ ≤ 30%)30%)
3/4/2013
ConclusionConclusion
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Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
Stripe noise is clearly visible in MODIS and VIIRS level 2 SST and Stripe noise is clearly visible in MODIS and VIIRS level 2 SST and cloud maskcloud mask
It introduces relative errors of up to It introduces relative errors of up to 0.3 K0.3 K at the pixel level at the pixel level
.. and compromises downstream SST applications - .. and compromises downstream SST applications - classification/clustering, cloud mask, thermal fronts detection…classification/clustering, cloud mask, thermal fronts detection…
Downsampling SST from 1 km (or 0.75 km for VIIRS) to 2/4 km Downsampling SST from 1 km (or 0.75 km for VIIRS) to 2/4 km resolution does not really mitigate the problem…resolution does not really mitigate the problem…
On-orbit calibration/characterization can reduce striping but cannot On-orbit calibration/characterization can reduce striping but cannot remove it fully, due to numerous factors contributing to stripe noise remove it fully, due to numerous factors contributing to stripe noise
Scene-based post-processing to reduce stripe noise is the only Scene-based post-processing to reduce stripe noise is the only practical approach for improved SST imagerypractical approach for improved SST imagery
3/4/2013
Current status and future workCurrent status and future work
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CurrentlyCurrentlyRotational buffer of destriped VIIRS SST SDRs (M12, M15, M16)Rotational buffer of destriped VIIRS SST SDRs (M12, M15, M16)Rotational buffer of ACSPO VIIRS SST with destriped BTsRotational buffer of ACSPO VIIRS SST with destriped BTs
Future workFuture workEstimate SST coefficients from destriped BTsEstimate SST coefficients from destriped BTs
Generate ACSPO SST with new SST coefficientsGenerate ACSPO SST with new SST coefficientsEvaluate quantitative impact on SST retrieval. Evaluate quantitative impact on SST retrieval.
Destriping VIIRS/MODIS SSTDestriping VIIRS/MODIS SST
3/4/2013
Thank you!Questions?
323/4/2013 Destriping VIIRS/MODIS SST
MODIS and VIIRS SST bandsMODIS and VIIRS SST bands
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Terra /Aqua MODIS Terra /Aqua MODIS
Resolution at NadirResolution at Nadir 1 km1 kmFPA -> 10 DetectorsFPA -> 10 Detectors
S/MWIRS/MWIR λλ (µm) (µm) NE∆T (K)NE∆T (K)
Band 20 Band 20 3.7 3.7 0.050.05Band 22Band 22 3.9 3.9 0.070.07Band 23Band 23 4 4 0.070.07
LWIRLWIR λ λ (µm) (µm) NE∆T (K)NE∆T (K)
Band 31Band 31 11 11 0.05K0.05KBand 32Band 32 12 12 0.05K0.05K
Suomi NPP VIIRSSuomi NPP VIIRS
Resolution at NadirResolution at Nadir 0.75 km0.75 kmFPA -> 16 DetectorsFPA -> 16 Detectors
S/MWIR S/MWIR λλ (µm) (µm) NE∆T (K)NE∆T (K)
M12M12 3.7 3.7 0.40K0.40K
LWIRLWIR λλ (µm) (µm) NE∆T (K)NE∆T (K)
M15 11M15 11 0.07K0.07KM16 12M16 12 0.07K0.07K
Destriping VIIRS/MODIS SST
3/4/2013