Radiometric Indices for Monitoring Soil Surfaces in South Tunisia
摘要
Due to wind erosion, the Hamma plain of Gabes (southern Tunisia) is considered an important source of sand for the surrounding areas. This erosion is a direct result of population pressure resulting in overgrazing and overexploitation of marginal lands which this plain has known for the last decade. The aim of this study is to develop a reliable methodology that uses Landsat satellite imagery to show the evolution of soil surfaces. This study was conducted using two Landsat scenes for the periods 1987 and 2000. This work is articulated according to the following axes: a) the use of the radiometric indices: vegetation Index NDVI, Brightness Index BI, and Colour Index CI and b) differences between the 2 years of the calculated radiometric indices. The results show that only 11% of the BIs, 9% of he CIs and 3% of the NDVIs were stable, the general changes of these indicators show that the study area has known degradation between these 2 dates. However, it would be more efficient to study changes with more satellite data in order to be more affirmative concerning the evolution of the study area