GEE is a petabyte archive of Earth Observations (EO) data that provides and relates data by using an efficient processing software coded in JavaScript or Python and describes these data in API format. This platform also offers an Application Programming Interface (API) service and other tools that scientists and researchers can use to analyze spatial big data by detecting and monitoring land cover changes and map trends and by quantifying the differences on the Earth’s surface. This engine contains archived satellite images taken all over the world and trillions of scientific measurements that date back by almost 40 years. Google Earth Engine (GEE) ( ) is a powerful web platform for the large-scale, cloud-based processing and analysis of geospatial data. Although its high salinity has caused birds to flee, Imlili Sebkha has created a favorable habitat for a Cichlid fish species associated with Tilapia guineensis, a species previously unknown in Morocco and whose northern limit was previously limited to the Senegal River. In fact, neither the general landscape nor the climatic data of the region suggest the existence of permanent salt water cavities that are capable of housing fish. However, these water pockets host many animals and fish ( Figure 1b) as reported during a scientific field trip in April 2017. While the median part of this sebkha holds over tens (161) of pockets of permanent water with diameters ranging from 1 m to 10 m, these pockets have a depth of approximately 4.6 decimetres and a water salinity of 24 g/L to 350 g/L ( Figure 1a). The water supply of these pockets is not random and is guaranteed by the small resurgences that appear at the lower part of the area, thereby preserving the moisture on the groundwater surface of the sebkha’s soil, especially at the western and northern edges of the area. Previous studies have shown that the palaeoclimatic regimes over Saharan Morocco have alternated between dry and wet periods throughout the Pleistocene and that the reserves of Saharan fossil aquifers are filled during humid periods. These landforms have evaporate–carbonate deposits with siliciclastics and form subaerial, prograding, and shoaling-upward sequences with an average thickness of 1 m or less. Sebkhas are supratidal sandflats that are formed along arid coastlines. Recent studies by the Scientific Institute of Rabat and the Nature Initiative Association of Dakhla have focused on Imlili Sebkha in southern Morocco, whose geomorphological structures have retained the impacts of previous climate conditions in the Sahara. Sebkhas are wet depressions in desert environments that are generally regarded as floodplains of significant environmental interest and have been closely linked to many environmental issues, such as climate change, water quality, wildlife habitat, and biodiversity. The sensitivity of these images to the variations in the slope of the topographic surface facilitated the geological and geomorphological analyses of desert zones and helped reveal the hydrological functions of Imlili Sebkha in discovering buried underground networks. Results show that radar images are not only well suited in studying desertic areas but also in mapping the water cavities in desert wetland zones. The main objective of this work was to investigate and evaluate the complementarity of optical Landsat, Sentinel-2 data, and Sentinel-1 radar data in such a desert environment. Optical and radar images were used to understand the functions of Imlili Sebkha in discovering underground hydrological networks. This work highlights the potential application of GEE in processing large amounts of satellite Earth Observation (EO) Big Data for the free, long-term, and wide spatio-temporal wet/dry permanent salt water cavities and moisture monitoring of Imlili Sebkha. Google Earth Engine (GEE) has revolutionized land monitoring analysis by allowing the use of satellite imagery and other datasets via cloud computing technology and server-side JavaScript programming. This region is mainly sandy, but its northern part holds permanent water pockets that contain fauna and flora despite their hypersaline water. Imlili Sebkha is a stable and flat depression in southern Morocco that is more than 10 km long and almost 3 km wide.
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