Daily Open Surface Water Dynamics and its response to rainfall Seasonality in Lake Chad Basin based on Earth Observation Time Series

Kurzfassung

The Sahel of Africa has often struggle under food insecurity and rising water scarcity with climate change. The Lake Chad Basin (LCB) is caught in a climate change-arm conflict trap, with rising environmental degradation. This study aims to (1) establish the daily and seasonal surface water dynamics of open surface water bodies in LCB and (2) how they respond to rainfall seasonality. Dense high temporal resolution remote sensing-derived Global WaterPack and ERA5-Land datasets (2003-2022) were used. The main methods involved time series decomposition, trend analysis, change points detection and statistical correlations. The results showed strong seasonal contrasts between surface water dynamics in lakes to dams/reservoirs in the basin. Both lakes and dams/reservoirs respond differently to rainfall seasonality, while important human controls were depicted on the seasonal patterns of surface water in dams/reservoirs. The entire cycle of Lake Chad showed recovery and dwindling phases, though with a slight recovery rate of 28.54km²/yr.