Analysis of snow cover dynamics in the Moroccan High Atlas using SPOT-VEGETATION data. (Surveillance environnementale a long terme dans les zones arides et semi-arides (Long-term environmental monitoring in arid and semiarid lands))

摘要

The Moroccan High-Atlas mountain range represents the most important "water tower" for the neighbouring arid regions, especially the Haouz plain in the surroundings of Marrakech. Water resources are facing enormous pressure and sustainable water management is a priority for the regional authority. Within this framework, a precise understanding of the processes and variables that drive the hydrological cycle is required. The contribution of liquid and solid precipitations to the runoff of the Tensift main sub-basins is of particular interest. In this context, we used a 7-year time series of SPOT-VEGETATION images to map the snow covered areas. The spatial and temporal variations of the snow pack were analysed over the entire High Atlas mountain range as well as over the five main tributary basins of the Haouz plain. These variations were evaluated against available hydro-climatic data (precipitation, temperature and runoff). This study demonstrates how remote sensing data can be used for long-term observation of the inter- and intra-annual variability of snow covered areas in a region where the meteorological observation network is insufficient. The potential of such data in studying the hydrology of semi-arid regions is also emphasized.