Sentinel-3: Lessons from AATSR/MERIS Synergy. Peter North Swansea University

Transcription

1 Sentinel-3: Lessons from AATSR/MERIS Synergy Peter North Swansea University

2 Introduction ESA projects relevant to Sentinel-3: Aerosol CCI MERIS/AATSR Synergy GlobAlbedo SEN4LST S3 Algorithm development (OLCI/SLSTR Synergy) What is your cal/val experience? L2/L3 algorithm developer and user Validation of aerosol, surface reflectance, albedo

3 AATSR Global Dataset (GPOD/CCI) Aerosol AOD and size distribution, surface reflectance Bevan, S.L., North et al., (2012), RSE 116,

4 Dual-view AATSR Aerosol retrieval vs Aeronet Mean bias (AERONET-AATSR) Bevan, S.L., North et al., (2012), RSE 116,

5 Aerosol CCI / AERCOM Analysis SU ATSR vs MISR 2.2 (Sep 2008 & annual average) Sep 2008 Average 2008 MISR v 2.2 SU AATSR v 3.0

6 Synergy retrieval MERIS/AATSR, OLCI/SLSTR MERIS RGB AATSR 870, 670, 555 nm (nadir) AATSR 1.2,1.1,3.7 µm (nadir) AATSR 870, 670, 555 nm (fwd)

7 AATSR / MERIS Synergy (ENVISAT , Sentinel ) Algorithm Correlation coeff. r Mean abs. error Bias Synergy Synergy (ang) Synergy (spec) Algorithm Correlation coeff. r Mean abs. error Bias Synergy Synergy (ang) Synergy (spec) North,P.R.J., Heckel A.et al., ESA Synergy ATBD (2010) 30/03/2012 7

8 SEN4LST- atmospheric correction 15/06/2010 8

9 ESA GlobAlbedo ( ) ((A)ATSR, MERIS, SPOT-VGT)

10 MERIS v AATSR Geolocation differences TOA reflectance, Sahel scene ( ) P of meeting 550 nm 670 nm 870 nm

11 Lessons Learned: Negative What DID NOT work well in the past? AATSR calibration (2008), esp wrt MERIS Registration: AATSR to MERIS AATSR nadir to AATSR forward Cloud screening? How can this be avoided for S3? Timeliness Proactive: find and deal with issues before users

12 Lessons Learned: Positive What DID work well in the past? Radiometric calibration good now? Potentially excellent instruments for long term climate records: aerosol, SDR temperature What should S3 do to build on this experience?

13 Recommendations Radiometric Stable algorithms from (near) outset IDEALLY error in TOA reflectance <0.01 Test instrument to instrument Geolocation Absolute, accounting for topography < 0.3 pixel SLSTR nadir to along-track <0.2 pixel SLSTR to OLCI < 0.2 pixel Collaboration with global networks useful AEROCOM, ASRVN etc

14 Cal/Val tools BEAM a useful framework to include tools Software geolocation / registration yet to be developed? Communication important on version, updates etc

15 References Bevan, S.L., North, P.R.J., Grey, W.M.F., Los, S.O. and Plummer, S.E. (2009). Impact of atmospheric aerosol from biomass burning on Amazon dry-season drought. Journal of Geophysical Research, 114, D09204, doi: /2008jd Bevan, S.L., North, P.R.J., Los, S.O., Grey, W.M.F., (2011). A global dataset of atmospheric aerosol optical depth and surface reflectance from AATSR, Remote Sensing of Environment, Remote Sensing of Environment (2012), pp North, P.R.J. (2002). Estimation of aerosol opacity and land surface bidirectional reflectance from ATSR-2 dual-angle imagery: operational method and validation. Journal of Geophysical Research 107 (D12), DOI: /2000JD000207: Grey, W.M.F., et al. (2006). Aerosol optical depth and land surface reflectance from multiangle AATSR measurements: Global validation and inter-sensor comparisons. IEEE Transactions on Geoscience and Remote Sensing, 44(8): North, P.R.J. et al. (2010) MERIS/AATSR Synergy Algorithms for Cloud Screening, Aerosol Retrieval, and Atmospheric Correction, Land Aerosol and Surface Reflectance ATBD, ESRIN Contract No /07/I-LG North, P.R.J. et al. (2010) Sentinel-3 L2 Products and Algorithm Definition: OLCI/SLSTR Level 2 and 3 Synergy Products, S3 L2-03 S2-SU-ATBD 30/03/

16 AATSR / MERIS Synergy (TOA reflectance initial AATSR calibration (2009))

17 AATSR Aerosol retrieval vs photometer (AERONET and MAN) Land: σ = ±0.025 ±0.35 τ a Ocean: σ = ±0.04 Bevan, S.L., North et al., RSE (in press)

18 AATSR Global Dataset Aerosol AOD and size distribution, surface reflectance Bevan, S.L., North et al., (2012), RSE 116,

19 Aeronet: 0.30 Synergy: 0.23 MERIS L2: - IBAER: /03/

20 AATSR / MERIS Synergy (ENVISAT , Sentinel ) Aeronet: 0.09 Synergy: 0.14 MERIS L2: 0.05 IBAER: /03/

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22 AATSR Sahel P of meeting MERIS Sahel

23 Abracos Hill AATSR MERIS