Cartographie et analyse de l’indice de chaleur par la télédétection de la température de surface du sol (LST) et de la mer (SST) dans la zone littorale et marine ouest de Mostaganem.

Abstract

This research focuses on applying a geomatics approach to satellite imagery to map and analyze the heat and coolness index in the western marine and coastal zone of Mostaganem (northwestern Algeria). The observation period lasted six months (January to May 2026). During this period, we used five (5) thermal images acquired between January and May 2026 by the STSTR (Sentinel 3) and TIRS (Landsat 8/9) sensors. Image processing involved resizing the images, correcting for atmospheric effects, retrieving the surface temperature recorded by the sensors, and converting it to degrees Celsius. These remote sensing methods, combined with GIS, made it possible to produce a land cover map based on the Corine Land Cover model comprising fifteen (15) thematic classes, with forests (40%), built-up areas (37%) and agricultural land (22%) dominating the continental zone. The vegetation index (NDVI) showed that 56% of the coastal zone is covered by vegetated surfaces compared to 44% by mineral surfaces. Bathymetrically, the seabed ranges from 0 to -94 m, with 85% of the marine area lying between -80 and -94 m depth. Five (5) monthly maps of marine and land surface temperatures were thus produced. The maps showed that the average temperature rose from 13.82°C in January to 19.87°C in May 2026, corresponding to a monthly variation of approximately 1.21°C. The average sea surface temperature (17.10°C) is lower than the average land surface temperature (17.12°C) due to the high variability in the emissivity of land surfaces. Remote sensing has proven to be effective, rapid, and spatially comprehensive in mapping and monitoring heat islands and cool islands. Our results have enabled the creation of a spatiotemporal map of surface temperature, which was traditionally limited to the specific location of the weather station. Our results remain useful for the sustainable planning and management of marine and terrestrial areas.