[H-TT15] Environmental Remote Sensing

[HTT15-P03] Vegetation response to soil water and precipitation amount changes in Central and Western Africa revealed by multiple satellite data

Ryotaro Suzuki², *Atsushi Higuchi^1,3 (1.Center for Environmental Remote Sensing (CEReS), Chiba University, Japan, 2.Division of Earth and Environmental Sciences, Graduate School of Science and Engineering, Chiba University, Japan, 3.Typhoon Science and Technology Research Center (TRC), Yokohama National University, Japan)

Keywords:Congo Basin, Land Surface Temperature, Leaf Area Index

Vegetation growth is affected by various environmental factors and is particularly strongly influenced by scarcity factors. The magnitude of water influence on vegetation growth may vary greatly depending on the season. In order to clarify how soil and groundwater variability affects vegetation change in central and western Africa, we analyzed seasonal and interannual variability and regional differences using multiple satellite observation data. In the Sahel region, which is in the semi-arid zone, we found that the vegetation change is caused by various factors, including seasonal and annual variations and regional differences.
In the semi-arid Sahel region, strong positive correlations were confirmed between leaf area index (LAI), advance rainfall index (API), and surface soil moisture, and strong negative correlations were found between LAI, surface temperature (LST), and clear-sky rate throughout the year. Strong positive correlations between LAI and LST were observed during some periods in tropical and savanna areas. Since no study confirmed a strong positive correlation between LAI and LST in the tropics, we focused our analysis on the Congo Basin, where a positive correlation was confirmed.
In the Congo Basin, LAI and LST were high in the wet season and low in the dry season. In the Congo Basin, where it is relatively sunny during the day, even in the rainy season, vegetation growth is optimal during the rainy season, and LAI is high. In the dry season, LST was low due to the large number of aerosols that blocked solar radiation caused by slash-and-burn agriculture in the savanna areas to the north and south of the basin. In the dry season, AOD (Aerosol Optical Depth) is very high, up to 0.91, and the positive correlation between LAI and LST indicates that aerosol-induced changes in solar radiation may affect vegetation growth.