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Published byMarvin Newton Modified over 9 years ago
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Some preliminary tests on VGT data over France J-L CHAMPEAUX, L FRANCHISTEGUY, S. GARRIGUES CNRM/GMME/MATIS
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Cloud mask evaluation Status map cloud mask. New VITO cloud mask (Lissens and al, Belgirate 2000) with thresholds tuned over the world applied to TOA reflectance: a pixel is declared clear if B0<493 OR SWIR<180. New tuned cloud mask with thresholds tuned over France for surface reflectance (S1 data): a pixel is declared cloudy if B0>=220 AND SWIR>=180 Comparison between:
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What strategy for the cloud mask? use the status map (poor quality) use the VITO thresholds Must be applied to TOA reflectances determine new thresholds on B0 for specific window
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Work on bidirectional effects: Evaluation of bidirectional effects in different solar-target-sensor configurations over homogeneous landcover areas Implementation and test of BDC method (B.Duchemin, CESBIO) Proposal VEGA2000: Determination of global albedo from VGT products
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VEGA2000 proposal : Determination of global albedo products from VGT instrument data for use in numerical weather forecast and climate models. L. FRANCHISTEGUY(CNRM/GMME) Preliminary study with a data set of VGT-P products (April 1998 – March 1999) a) Atmospheric corrections : SMAC TOA reflectances surface reflectances b) BRDF kernel-driven model inversion : correction of bidirectional effects (30 days compositing period with a sliding period of 10 days). c) Retrieval of land surface albedo (directional albedo) for a 100*100 km domain located in southeast part of France.
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Method for retrieval of surface properties Inversion of a BRDF model : s, v, = k 0 + k 1 f 1 s, v, + k 2 f 2 s, v, (model of Roujean et al., 1992) K0: Normalized reflectance for s =0 and v =0
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DECIDUOUS PIXELS ( South of France)A
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Unsupervised classification using 10 days MVC ( from 1/1/2000 to 31/09/2000 over SO France Corine Land Cover dataset at 1km resolution
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Unsupervised classification using 10 days MVC from 1/1/2000 to 31/09/2000 over SO France
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