Geographia Technica, Vol 19, Issue 2, 2024, pp. 139-151
THE CONTRIBUTION OF REMOTE SENSING IN HIGHLIGHTING THE RESILIENCE OF RANGELANDS THROUGH INDICATORS OF LAND SURFACE TEMPERATURE AND THE NORMALIZED DIFFERENCE VEGETATION INDEX IN THE TIHAMA ALLUVIAL PLAIN
Azaiez NAIMA 
ABSTRACT: The rangelands form a precious heritage of an ancient agro-pastoral system in Saudi Arabia, known for its livestock based on camel. The extensive rangelands in the Tihama alluvial plain are facing a deterioration in climatic conditions. In the past, the monitoring of these rangelands, in general, was done by direct vegetation surveys in the field. Currently, researchers have greatly benefited from the contribution of remote sensing, especially with the eighth generation of Landsat satellite images, making it possible to provide values relating to the thermal emissivity of the ground surface, obtained in the two bands 10 and 11. This method allows the calculation of algorithms and the creation of advanced models. The creation of a multi-source database established on the exploitation of the Geographic Information System and remote sensing was necessary to identify the local conditions that have favored the resilience of the plant cover, and the identification of multiple intervention methods appropriate to each sector according to its state of resilience. The results revealed a reduction in soil temperature average, increasing from 29.5 - 42.5°C in 2013 to 38.2 - 25.3°C in 2022. These changes are accompanied by a significant expansion of the vegetation cover, estimated at 26% over the same period despite the substantial climate changes the region has experienced. In the Tihama plain the LST index is significantly influenced by the type of deposit, soil salinity, soil moisture, as well as the density of soil benches. On the adjacent eastern and north-eastern slopes, the values are much lower due to the altitude, the sheltered position, the inclination of the angle of incidence of the sun's rays and the disparity in the colours of the rocky outcrops.
Keywords: LST index, NDVI index, thermal comfort, plant resilience, rangelands, surface humidity.
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