Title :
Variability analysis of the transitory climate regime as defined by the NDVI/Ts relationship derived from NOAA-AVHRR over Canada
Author :
Fillol, E.J. ; Royer, A.
Author_Institution :
Centre d´´Applications et de Recherches en Teledetection, Sherbrooke Univ., Que., Canada
Abstract :
This research work outlines an original method for climate observation by remote sensing based on the local combination of normalized difference vegetation index (NDVI) and land surface temperature (Ts) measurements acquired by the NOAA-AVHRR sensor. It explores the phenomenon of linearity observed between Ts and the NDVI, which varies from positive to negative according to the conditions of the land surface energy budget regime and the vegetation type. Over vegetation, the decreasing relationship of Ts in relation to the NDVI (negative regression) due to vegetation cover transpiration is well known. However, over soils with sparse vegetation, bare soil, lichens or tundra, the relationship is reversed (positive regression) due to the high surface albedo which influences Ts values. The method is first demonstrate using full spatial and temporal resolution HRPT images over the BOREAS area corrected for atmospheric effects and screened for cloud cover in comparison with temperature and precipitation data. The method is then applied to composite images from the PAL multi-annual database at a resolution of 8 km and for Canada overall. It permits the determination of the ecotone position separating the forest from the tundra and the monitoring of the inter-annual fluctuations related to climatic variations and global warming.
Keywords :
atmospheric temperature; global warming; image resolution; soil; vegetation mapping; BOREAS area; Canada; HRPT images; NDVI vegetation index; NOAA-AVHRR sensor; PAL multiannual database; atmospheric effects; atmospheric temperature; climatic variations; composite images; ecotone position; forest; global warming; image resolution; interannual fluctuations; land surface energy; land surface temperature; negative regression; precipitation; remote sensing; soils; spatial resolution; surface albedo; temporal resolution; transitory climate regime; transpiration; tundra; variability analysis; vegetation mapping; Image resolution; Land surface; Land surface temperature; Linearity; Remote sensing; Sensor phenomena and characterization; Soil; Spatial resolution; Temperature sensors; Vegetation mapping;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2003. IGARSS '03. Proceedings. 2003 IEEE International
Print_ISBN :
0-7803-7929-2
DOI :
10.1109/IGARSS.2003.1294612