Investigating the Changes within the Lake Chad Basin Using GRACE and LANDSAT Imageries

Abstract

Understanding the spatio-temporal characteristics of water storage changes is crucial for Lake Chad, a basin facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, scarcity of in situ measurements combined with scale limitations of traditional methods used in its hydrological characterization further makes it hard to assess and manage this vital water resource. The primary objective of this study is to apply remotely sensed and modeled data over the lake area in order to investigate the inter-annual and seasonal terrestrial water storage changes within the lake area and its effect on the lake's surface water. The data used in this study includes; monthly gravity field data from the Gravity Recovery and Climate Experiment (GRACE) mission from which water storage trends within the basin were determined, Rainfall data from the Tropical Rainfall Measuring Mission (TRMM) shows an increase in seasonal pattern of rainfall in this area. This study, covers a period from 2003-2013. Results show that GRACE Terrestrial Water Storage within the basin has been somewhat stable with the highest averaged values at 0.69cm/year occurring in 2012. Correlation analysis indicated a time lag of about a month exists between TWS and rainfall. To understand the possible causes and effects these changes has on the surface water of the lake, investigations using Landsat imagery are underway. These results could serve as an insight on the availability of water resources in the Lake Chad Basin and could also provide baseline data which could be used to monitor the lake for current and future management purposes.