Undersökning av sambandet mellan strålningstemperatur och NDVI i Sahel
Physical geographyGeomorphologyClimate changeModellingSatellite dataRemote sensingSatellitdataFjärranalysModelleringKlimatförändringarPedologyClimatologyCartographyNaturgeografiGeomorfologiMarkläraKartografiKlimatologiEarth and Environmental Sciences
Several studies have analysed the relationship between Normalised DifferenceVegetation Index (NDVI) and radiative surface temperature. A main goal for moststudies have been to find the best method for carrying out land cover classificationsand to study land cover changes, based on a combination between the twoparameters. Since atmospheric components have a significant influence on bothparameters, most applications were based on multi-temporal data. The quality of theindividual values in such a combination is improved, but the biophysical justificationis uncertain. This study presents a different method, based on only the combination ofvalues that have been registered the same day and about the same time of the day.125 daily images of NDVI and 250 images of radiometric temperature were used inorder to analyse the relationship between (1) NDVI and radiative temperature and (2)NDVI and relative temperature difference between early morning and mid-day.Results between NDVI and radiative temperature show a significant negativecorrelation on areas where a distinct growing season develops, and a strong positivcorrelation where vegetation is abscent throghout the season. When analysing NDVIand temperature difference, further processing was needed in order to compare theparameters due to cloud contamination.