potentials for detecting canopy water stress using geostationary msg
Transcription
potentials for detecting canopy water stress using geostationary msg
POTENTIALS FOR DETECTING CANOPY WATER STRESS USING GEOSTATIONARY MSG-SEVIRI SWIR DATA Rasmus Fensholt, *Department of Geography and Geology, University of Copenhagen, Denmark Co-workers; Silvia Huber*, Simon R. Proud*, Mads O. Rasmussen*, Inge Sandholt, Simon Stisen**, Cheikh Mbow, UCAD Senegal 1 Water; primary potential climatic constraint to plant growth (40% of Earth's Terrestrial Surface) Outline: • EO-based Canopy Water Stress detection • In situ measured Canopy Water Stress Potential climatic constraints to plant growth. Nemani et al. (2003) • Results & validation - from point observations - validation in the spatial domain 2 EO-based Canopy Water Stress detection Absorption by leaf water occurs in SWIR - Shortwave infrared reflectance is negatively related to leaf water content - Increased reflectance in SWIR is the most consistent leaf reflectance response to plant stress in general, including water stress. Prospect+Sail models; Zarco-Tejada and Ustin 2001 SWIR reflectance influenced by; Leaf water content Leaf internal structure Leaf dry matter content NIR reflectance influenced by; Leaf internal structure Leaf dry matter content Cw (water thickness)= 0.001 Cw = 0.03 CW =0.001 MSG Band 1 Band 2 Band 3 CW =0.03 3 EO-based Canopy Water Stress detection - Water Stress index development Physically based studies; Tucker, 1980; Fourty and Baret, 1997 Laboratory measurements; Hunt, Rock, & Nobel, 1987 Carter, 1994 Physically – Emperically applied to sat sensors… Hunt and Rock, 1989 – Landsat TM Moisture Stress Index Gao, 1996 - AVIRIS Normalized Difference Water Index Serrano, Ustin, Roberts, et al., 2000 - AVIRIS Zarco-Tejada and Ustin, 2003 - MODIS Simple Ratio Water Index Ceccato et al., 2001; 2002 - SPOT VGT. Fensholt and Sandholt, 2003 - MODIS Shortwave Infrared Water Stress Index Rubio et al., 2006 - MODIS Normalized Difference Water Index 7 Trombetti et al., 2008 – MODIS Shortwave Infrared Ratio Fensholt et al. 2010 – SEVIRI MSG Shortwave Infrared Water Stress Index 4 Variable performance validation Mauritania Mali Niger Chad From the Dahra test site in semi-arid Senegal Burkina Faso Sudan Ethiopia Nigeria Senegal Northern Sahel ± Southern Sahel 0 500 1,000 2,000 Kilometers Dahra Senegal 900 800 Annual Rainfall 700 600 500 400 300 200 100 0 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 5 Dahra test site setup Since 2004 Since 2002 - Air temperature, - Relative humidity - Wind speed - Net radiation Global radiation - Ground heat flux Full surface energy balance Flux profile estimates of latent and sensible heat Windspeed - Precipitation & surface temperature - Soil moisture & soil temperature profiles - Sensor specific reflectances, matching various sensors for estimation of spectral vegetation indices & fAPAR. Ancillary sampling: biomass, vegetation height, root depth etc. Measurements every 15 minutes Air temperature & humidity Global radiation Net radiation IR radiometer Spectral Reflectance 6 Dahra test site setup Since 2008 - LST (collaboration with Institute of Technology (KIT) Institute for Meteorology and Climate Resarch (IMK) Atmospheric Trace Gases and Remote Sensing (ASF) - Poster: Rasmussen, Mads, O. et al. Intercomparison between SEVIRI LST-products And comparison with in situ LST measurements 7 East West Since 2010 - ASD spectroradiometers (350-1800 nm) 45° 45° 30° 30° 15° 0° 15° - Eddy covariance fluxes (water and carbon) Collaboration with University of Lund Eddy Flux Tower 8 Prospect+Sailh models; Zarco_Tejada and Ustin 2001 Cw (water thickness)= 0.001 Can SWIR based canopy water status be detected 0,8 20 In theNDVIfield? ASD NADIR MSG config 0,7 Soil moisture 5cm 16 0,6 ASD data 2010 preliminary results.... 12 0,4 Poster: Huber, S. et al. 0,3 Detecting drought related stress with field 0,2 spectroradiometric measurements of 0,1 natural grass savanna 0 8 Soil Moisture NDVI 0,5 Cw = 0.03 4 247 244 241 238 235 232 229 226 223 220 217 214 211 208 205 202 0 199 -0,1 35 DOY 238 DOY 240 25 20 DOY 242 DOY 244 15 10 45° 5 45° 30° 30° 15° 0° 15° 0 35 0 40 0 45 0 50 0 55 0 60 0 65 0 70 0 75 0 80 0 85 0 90 0 95 10 0 0 10 0 5 11 0 0 11 0 5 12 0 0 12 0 5 13 0 0 13 0 5 14 0 0 14 0 5 15 0 0 15 0 5 16 0 0 16 0 5 17 0 0 17 0 5 18 0 00 Reflectance (%) 30 9 Mauritania Mali Niger Chad Burkina Faso Sudan Ethiopia Nigeria Senegal Northern Sahel ± Southern Sahel 0 500 1,000 2,000 Kilometers 0,8 20 0,7 NDVI ASD NADIR MSG config SIWSI ASD NADIR MSG config. Soil moisture 5cm Soil moisture 10cm 16 0,6 0,5 8 Soil Moisture 0,3 0,2 0,1 4 0 247 245 243 241 239 237 235 233 231 229 227 225 223 221 219 217 215 213 211 209 207 205 203 0 201 -0,1 199 NDVI and SIWSI 12 0,4 10 4-day BRDF corrected reflectances Febr. 2008 Annual BRDF corrected reflectances avg. 2008 MSG SEVIRI data University of Copenhagen SMAC corrected (MOD08 input), reflectances BRDF (NBAR) Proud, S. R. 2010… Poster: Evaluating the effectiveness of producing BRDF models from SEVIRI surface reflectance data. 11 0,9 Terra MODIS NDVI Aqua MODIS NDVI IN situ MODIS NDVI GoogleEarth 0,6 0,5 0,4 0,3 0,2 0,8 0,7 MODIS 500m y = 1,01x - 0,02, R2 = 0,99 0,6 MODIS 250m y = 0,99x - 0,01, R2 = 0,99 0,8 Test site 0,7 Terra MODIS y = 0,92x + 0,009, R2 = 0,70 15 MODIS NDVI (4.5 1km 2 aggregated) 83 21 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 15 7 18 2 MODIS NDVI 21 3 250m 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 15 7 18 2 21 3 24 4 27 5 30 6 7 0,1 2003 2004 2005 2006 2007 0,5 2008 0,5 0,4 0,4 0,3 0,3 0,2 0,2 0,1 MODIS 500m MODIS 250m Dahra Village 0 0 0,1 0,2 0,3 3 km 2002 0 0,6 Aqua MODIS y = 0,95x + 0,001, R2 = 0,76 2008 2009 2010 18 21 2 24 3 27 4 30 5 6 MODIS NDVI 500m resolution 0,8 Dahra test site in0,7Senegal Terra MODIS 0,1 Aqua MODIS 0 0,4 0,5 0,6 MODIS NDVI 250 & 500 m 0,7 0,8 0 0,1 0,2 0,3 0,4 0,5 In situ NDVI 0,6 0,7 0,8 Mauritania Mali Niger Chad Burkina Faso Sudan Ethiopia Nigeria Senegal Northern Sahel ± Comparing MSG SEVIRI vegetation indices with in situ measuremets Southern Sahel 0 500 1,000 2,000 Kilometers 0,7 MSG DGG NDVI MSG In situ MSG LSA SAF NDVI 0,6 0,4 0,3 0,2 0,1 23-10-2008 16-10-2008 09-10-2008 02-10-2008 25-09-2008 18-09-2008 11-09-2008 04-09-2008 28-08-2008 21-08-2008 14-08-2008 07-08-2008 31-07-2008 24-07-2008 17-07-2008 10-07-2008 03-07-2008 26-06-2008 19-06-2008 12-06-2008 05-06-2008 29-05-2008 0 22-05-2008 NDVI 0,5 13 60.4% ± 0 500 66.7% Senegal In situ NDVI (MODIS config. Daily avg) Northern Sahel Southern Sahel 1,000 2,000 0,7 Kilometers 0,6 51.2% 0,5 600 0,4 60.9% 0,3 66.5% 200 0,2 0 Julian day 2008 10 10 8 8 6 6 4 4 In situ NDVI and Root depth (m) Mali 0,1 0,5 0,05 0,4 0 0,3 -0,05 0,2 -0,1 0,1 -0,15 0 2 2 -0,2 -0,1 -0,25 -0,2 0 0 -0,3 -0,3 NDVI and SIWSI indices NDVI and SIWSI indices Burkina Faso 21-10-2008 21-10-2008 Mauritania 14-10-2008 14-10-2008 67.7% 07 -1 020 08 14 -1 020 08 21 -1 020 08 Root depth 07-10-2008 07-10-2008 30-09-2008 30-09-2008 Aboveground Biomass 23-09-2008 23-09-2008 16-09-2008 16-09-2008 09 -0 920 08 16 -0 920 08 23 -0 920 08 30 -0 920 08 800 09-09-2008 09-09-2008 02-09-2008 02-09-2008 12 12 26-08-2008 26-08-2008 12 -0 820 08 19 -0 820 08 26 -0 820 08 02 -0 920 08 400 19-08-2008 19-08-2008 12-08-2008 12-08-2008 05-08-2008 05-08-2008 29-07-2008 29-07-2008 22-07-2008 22-07-2008 14 14 15-07-2008 15-07-2008 1000 15 -0 720 08 22 -0 720 08 29 -0 720 08 05 -0 820 08 24 -0 620 08 01 -0 720 08 08 -0 720 08 2 Above ground Biomass (g/m ) 1200 08-07-2008 08-07-2008 01-07-2008 01-07-2008 24-06-2008 24-06-2008 soilmoisture moisture(Vol (Vol%) %) soil Evaluation of EO-based SIWSI from in situ measuremets - 2008 Niger Chad Sudan Nigeria Ethiopia 0,8 0,1 0 0,2 0,7 0,15 0,6 14 0 500 Mali 1,000 14 12 0,1 0,5 10 0,05 0,4 8 0 0,3 6 -0,05 0,2 -0,1 0,1 4 -0,15 0 2 -0,2 -0,1 0 NDVI and SIWSI indices NDVI and SIWSI indices Burkina Faso 22-10-2006 ± 15-10-2006 Evaluation of EO-based SIWSI from in situ measuremets – 2006 08-10-2006 01-10-2006 24-09-2006 17-09-2006 10-09-2006 03-09-2006 27-08-2006 20-08-2006 13-08-2006 06-08-2006 30-07-2006 23-07-2006 16-07-2006 09-07-2006 02-07-2006 25-06-2006 soil moisture moisture (Vol (Vol %) %) soil Mauritania Niger Chad Sudan Senegal Nigeria Ethiopia Northern Sahel Southern Sahel 2,000 Kilometers 0,2 0,7 0,15 0,6 -0,25 -0,2 -0,3 15 soilmoisture moisture(Vol (Vol%) %) soil -0,2 -0,1 -0,25 -0,2 0 0 -0,3 -0,3 Burkina Faso 0 500 1,000 22-10-2007 22-10-2007 ± 15-10-2007 15-10-2007 Evaluation of EO-based SIWSI from in situ measuremets - 2007 08-10-2007 08-10-2007 01-10-2007 01-10-2007 24-09-2007 24-09-2007 17-09-2007 17-09-2007 10-09-2007 10-09-2007 03-09-2007 03-09-2007 27-08-2007 27-08-2007 20-08-2007 20-08-2007 13-08-2007 13-08-2007 06-08-2007 06-08-2007 30-07-2007 30-07-2007 23-07-2007 23-07-2007 16-07-2007 16-07-2007 09-07-2007 09-07-2007 02-07-2007 02-07-2007 12 12 10 10 8 8 6 6 4 4 NDVI and SIWSI indices NDVI and SIWSI indices 2 2 25-06-2007 25-06-2007 Mauritania Mali Niger Chad 14 14 Sudan Senegal Nigeria Ethiopia Northern Sahel Southern Sahel 2,000 Kilometers 0,2 0,7 0,15 0,6 0,1 0,5 0,05 0,4 0 0,3 -0,05 0,2 -0,1 0,1 -0,15 0 16 Mali Burkina Faso 1,000 14 12 0,5 10 0,4 8 0,3 6 0,2 0,1 4 0 2 -0,1 0 NDVI and SIWSI indices 500 17-11-2009 0 10-11-2009 ± 03-11-2009 Evaluation of EO-based SIWSI from in situ measuremets - 2009 27-10-2009 20-10-2009 13-10-2009 06-10-2009 29-09-2009 22-09-2009 15-09-2009 08-09-2009 01-09-2009 25-08-2009 18-08-2009 11-08-2009 04-08-2009 28-07-2009 21-07-2009 14-07-2009 07-07-2009 30-06-2009 23-06-2009 16-06-2009 09-06-2009 02-06-2009 26-05-2009 soil moisture (Vol %) Mauritania Niger Chad Sudan Senegal Nigeria Ethiopia Northern Sahel Southern Sahel 2,000 Kilometers 0,7 0,6 -0,2 -0,3 17 Senegal In situ NDVI (MODIS config. Daily avg) ± 0 Northern Sahel 500 Southern Sahel 66.7% 1,000 2,000 0,7 Kilometers 0,6 51.2% 0,5 600 0,4 60.9% 0,3 66.5% 200 0,2 0 Julian day 2008 0,1 10 0,05 8 0 6 -0,05 -0,1 4 -0,15 2 -0,2 0 NDVI and SIWSI indices 60.4% Mali In situ NDVI and Root depth (m) Burkina Faso 21-10-2008 Mauritania 14-10-2008 67.7% 07 -1 020 08 14 -1 020 08 21 -1 020 08 Root depth 07-10-2008 30-09-2008 Aboveground Biomass 23-09-2008 16-09-2008 09 -0 920 08 16 -0 920 08 23 -0 920 08 30 -0 920 08 800 09-09-2008 02-09-2008 12 26-08-2008 12 -0 820 08 19 -0 820 08 26 -0 820 08 02 -0 920 08 400 19-08-2008 12-08-2008 05-08-2008 29-07-2008 22-07-2008 14 15-07-2008 1000 15 -0 720 08 22 -0 720 08 29 -0 720 08 05 -0 820 08 24 -0 620 08 01 -0 720 08 08 -0 720 08 2 Above ground Biomass (g/m ) 1200 08-07-2008 01-07-2008 24-06-2008 soil moisture (Vol %) Evaluation of EO-based SIWSI from in situ measuremets - 2008 Niger Chad Sudan Nigeria Ethiopia 0,8 0,1 0 0,2 0,15 -0,25 -0,3 18 12 Soil moisture 5 cm MSG SEVIRI SIWSI Terra MODIS SIWSI Aqua MODIS SIWSI 0,2 0,15 MSG SEVIRI daily BRDF SIWSI Soil moisture (vol%) 10 0,1 0,05 8 0 6 -0,05 -0,1 4 -0,15 2 -0,2 0 800 MSG SEVIRI SIWSI (9 am. 4 pm. local solar time) 0,25 14 -0,25 253 254 255 Net radiation 256 257 258 Sensible heat flux 259 260 Latent heat flux 261 262 263 264 265 266 267 268 262 263 264 265 266 267 268 Soil flux 700 600 Watt/m 2 500 400 300 200 100 0 253 254 255 256 257 258 259 260 261 269 19 - Spatio-temporal Evaluation of SIWSI (20 pixels, 320 km2) using NOAA RFE rainfall as surface water status indicator 20 30 -0 506 20 -0 08 613 200 8 -0 62 20 0 -0 08 627 20 -0 08 604 20 -0 08 711 20 -0 08 718 20 -0 08 725 200 -0 8 72 01 0 -0 08 808 20 -0 08 815 20 -0 08 822 20 -0 08 829 20 -0 08 805 200 -0 8 92 12 0 -0 08 919 20 -0 08 926 20 -0 08 903 20 -1 08 010 200 -1 8 02 17 0 -1 08 024 20 -1 08 020 08 Soil moisture (Vol %) 20 18 16 14 MSH model soil moist 25 cm in situ soil moist 30 cm MSH ETa 12 2 0 6 5 10 4 8 3 6 2 4 1 EvapoTranspiration (mm/day) - Spatio-temporal evaluation of MSG SIWSI using a hydrological model (Mike-She distributed model) • Is the model able to simulate water status at the Dahra test site? • Are model inputs (RFE rainfall) reliable? 7 0 21 - Spatio-temporal evaluation of MSG SIWSI using a hydrological model (Mike-She distributed model) Preliminary data analysis… 22 23 SIWSI NDVI ETa 24 Conclusions and perspectives - SWIR sensitivity to Canopy water content (semi-arid grass land) - MSG sensitivity on a daily scale - Biomass dependancy - SWIR based indices complementary to VIS/NIR approaches - SWIR based indices more robust to atm correction than VIS/NIR 0.9 90 Soil moisture 10 cm 80 0.7 70 2002 2003 2004 2005 2006 2007 2008 2009 0.6 2010 60 0.5 50 0.4 40 0.3 30 0.2 20 0.1 10 0 15 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 157 182 213 244 275 306 7 18 212 243 274 305 6 MODIS NDVI In situ MODIS NDVI Rainfall (mm) adn Soil moisture (vol%) Rainfall 0.8 0 25