Sen 4 LST Atmospheric Correction A Heckel P
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Sen 4 LST Atmospheric Correction A. Heckel, P. North
Overview • Atmospheric Correction based on existing Synergy aerosol retrieval • Demonstrates synergistic use of combined AATSR and MERIS data set • Already implemented and operational in BEAM • Will be implemented as synergy product for SLSRT and OLCI a. heckel@swansea. ac. uk 15/06/2010 2
Synergy approach Iterate through a range of aerosol models Ma and t 550 to minimise E AATSR RTOA(l, W) Minimise Eang (t) using angular constraint MERIS RTOA(l) Minimise Espec (t) using spectral constraint E (t) = Eang(t) + Espec(t) RTOA Rsurf l. AATSR l. MERIS W t E (t) Eang(t) Espec(t) and Top of atmosphere reflectance Surface reflectance Spectral bands AATSR Spectral bands MERIS AATSR view (Nadir / Fward) AOT at 550 nm Error of model fit Error of angular constraint Error of spectral constraint Weighting coefficients Rsurf(l. MERIS), Rsurf(l. AATSR, WAATSR), t 550 and additional aerosol parameter a. heckel@swansea. ac. uk 15/06/2010 3
Invertible models of surface reflectance Minimise Eang (t) using angular constraint Minimise Espec (t) using spectral constraint Spectral: Angular: E (t) = Eang(t) + Espec(t) a. heckel@swansea. ac. uk • Weighting factors , depend on TOA NDVI 15/06/2010 4
Retrieval outline - TOA RGB • Top of atmosphere False color RGB of Spain 23. July 2008 a. heckel@swansea. ac. uk 15/06/2010 5
Retrieval outline - AOD coarse • Retrieved AOD using current MERIS-AATSR Synergy algorithm a. heckel@swansea. ac. uk 15/06/2010 6
Retrieval outline - AOD interpolated • AOD after gap filling and interpolation to original resolution • Currently still issues with islands and interpolation to ocean AOD a. heckel@swansea. ac. uk 15/06/2010 7
Retrieval outline - atmospherically corrected RGB a. heckel@swansea. ac. uk 15/06/2010 8
MERIS-AATSR-Synergy Validation a. heckel@swansea. ac. uk 15/06/2010 9
AARDVARC Aerosol size retrieval (AATSR only) Bevan, S. L. , North et al. , RSE (submitted)
Aerosol CCI - Aerocom Climatology AOD • Climatology based on Aerocom aerosol models adjusted using Aeronet • Provides monthly maps of AOD © Steffan Kinne, MPI Hamburg, Germany a. heckel@swansea. ac. uk 15/06/2010 11
Aerosol CCI - Aerocom Climatology Type • Climatology based on Aerocom aerosol models adjusted using Aeronet • Provides monthly maps of AOD and aerosol type © Steffan Kinne, MPI Hamburg, Germany a. heckel@swansea. ac. uk 15/06/2010 12
Aerosol CCI - AOD validation (AATSR only) Mar 2008 Jun 2008 Sep 2008 Dec 2008 • Aerosol CCI L 2 comparison of AOD 550 vs Aeronet • Best results achieved using climatology prescribing aerosol type fractions
Next Steps… • Further revision of the Synergy code • Adopting additional improvements made since MERIS-AATSR Syngery • Further testing on the retrieval of aerosol size a. heckel@swansea. ac. uk 15/06/2010 14