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NAFE 3rd Workshop 17-18 Sept 2007 Vegetation Water Status from Optical Remote Sensing ___ Preliminary results from the NAFE05 experiment Philippe Maisongrande, Julian Kuhlmann Gilles Boulet, Bertrand Guerrero Slide 2 NAFE 3rd Workshop 17-18 Sept 2007 Optical Remote Sensing and VWC -Rational (1)- REDNIR SWIR NDVI=( nir- red) ( nir+ red) SWVI=( nir- swir) ( nir+ swir) Slide 3 NAFE 3rd Workshop 17-18 Sept 2007 Optical Remote Sensing and VWC -Rational (1)- REDNIR SWIR NDVI=( nir- red) ( nir+ red) SWVI=( nir- swir) ( nir+ swir) stressed unstressed Slide 4 NAFE 3rd Workshop 17-18 Sept 2007 Precipitation climatology -Australian Bureau of Meteo.- 1998->2006 average NDVI -Spot/VEGETATION data- Slide 5 NAFE 3rd Workshop 17-18 Sept 2007 VEGETATION onboard SPOT 4&5 Operational Mission (available free data on the web) 4 channels: Blue (0.43 - 0.47 m) Red(0.61 - 0.68 m) Near InfraRed (NIR)(0.78 - 0.89 m) Shortwave InfraRed(1.58 - 1.75 m) Dayly global coverage (at km2 res.) & 10day synthesis corrected for atmospheric effects of consistent archive9 years of consistent archive (1998-2006) A third mission under study MODIS differences (aqua&terra) 1.3 and 2.3 m 250m (Red&NIR) 500m otherwise No 1.6 m (aqua) Slide 6 NAFE 3rd Workshop 17-18 Sept 2007 El Nio & La Nia Events Maisongrande, Kuhlmann et al. MODSIM 2007 Slide 7 NAFE 3rd Workshop 17-18 Sept 2007 NDVI & SWVI vs Southern Oscillation Index Maisongrande, Kuhlmann et al. MODSIM 2007 NDVI SWVI Slide 8 NAFE 3rd Workshop 17-18 Sept 2007 RATIONAL (2) VWC ~ 1-(EC/AC) -> A*NDVI-B*SWVI+C > NDVI-SWVI ( ) Slide 9 NAFE 3rd Workshop 17-18 Sept 2007 (NDVI-SWVI) vs Southern Oscillation Index 1.5*D-0.75 0.15+SOI/100 Maisongrande, Kuhlmann et al. MODSIM 2007 Slide 10 NAFE 3rd Workshop 17-18 Sept 2007 FOCUS on NAFE2005 Database handling and organization (multi-layer consistency) Preparation of the Land Use Land Cover map (LULC) Preliminary analysis -Satellite indices against in situ measurements of Vegetation Water Content (VWC) Slide 11 NAFE 3rd Workshop 17-18 Sept 2007 Insitu Ancilary Satellite (or infered from it) DATABASE organization and handling exhaustive sparse Slide 12 NAFE 3rd Workshop 17-18 Sept 2007 Slide 13 Slide 14 NDVI & SWVI vs Southern Oscillation Index Maisongrande, Kuhlmann et al. MODSIM 2007 Slide 15 NAFE 3rd Workshop 17-18 Sept 2007 Open woodland Bare soil forest crop Native grass Slide 16 NAFE 3rd Workshop 17-18 Sept 2007 Open woodland Bare soil forest crop Native grass NDVI SOI Slide 17 NAFE 3rd Workshop 17-18 Sept 2007 NDVI_VGT vs VWC Slide 18 NAFE 3rd Workshop 17-18 Sept 2007 SWVI_VGT vs VWC Slide 19 NAFE 3rd Workshop 17-18 Sept 2007 _VGT vs VWC Slide 20 NAFE 3rd Workshop 17-18 Sept 2007 2 1 3 11 37 36 5 15 6 4 Regression between VGT VIs and VWC for various classes r2r2 Slide 21 NAFE 3rd Workshop 17-18 Sept 2007 01/11 03/11 7/ 11 9 /11 12 of November 17 of November 21 of November SWVI SPOT/VGT2 10day composite images SPOTVGT2 Dates composite MODIS Available and clear dates dates Imgclass.m SPOT/ VEGETATION 10day composite products = Each S10 image is a patchwork of dates S30 S31 S32 Slide 22 NAFE 3rd Workshop 17-18 Sept 2007 R2 sensitivity to the time lag between field VWC and satellite measurements Slide 23 NAFE 3rd Workshop 17-18 Sept 2007 NDVI 12/11 MODIS vs VGT Slide 24 NAFE 3rd Workshop 17-18 Sept 2007 NDVI_MODIS vs VWC Slide 25 NAFE 3rd Workshop 17-18 Sept 2007 NDVI_VGT vs VWC Slide 26 NAFE 3rd Workshop 17-18 Sept 2007 2 1 3 13 38 40 6 16 6 6 Regression between MODIS VIs and VWC for various classes r2r2 Slide 27 NAFE 3rd Workshop 17-18 Sept 2007 2 1 3 11 37 36 5 15 6 4 Regression between VGT VIs and VWC for various classes r2r2 Slide 28 NAFE 3rd Workshop 17-18 Sept 2007 R2 sensitivity to the time lag between field VWC and MODIS measurements Slide 29 NAFE 3rd Workshop 17-18 Sept 2007 Strong effort on the organization collect of VGT images, consistency Classification labeled thanks to in situ inquiries, but the labeling has to be considered with care. CONCLUSIONS Toward modeling studies involving prepared layers, (optical and thermal data). SMOS L2 ->L4 ; NAFE06 Investigation on the potential of optical sat. data to assess the plant water status: Disappointing with SPOT/VGT (1km2=pixel heterogeneity) Encouraging with MODIS (250m) Relative good score for SWVI (2.1 m) compared to NDVI and . (no way to evaluate 1.6 m @250m resolution)