Vegetation response to soil moisture and groundwater in west-central Africa revealed by satellite observations

In this article, we explore the soil water effect on vegetation growth in west-central Africa using remotely sensed near-surface soil moisture content (nSMC), terrestrial water storage anomaly (TWSA), and leaf area index (LAI). TWSA is the only data to reflect deeper soil water used by perennial plants with their deep root systems, which microwave sensors cannot observe. However, deep groundwater complicates investigating the water availability of plants using TWSA. We confirmed that the TWSA's slope during the dry season, which might be caused by vegetation transpiration, was steeper towards equatorial regions. Our results show that the relationship between LAI and the TWSA's inclination during the dry season was negatively correlated in areas where the LAI was below 2 and the precipitation was less than 40 mm/month. This finding might enable us to investigate the water availability of perennial plants by focusing on the TWSA's slope during the dry season.