Tracking Rainfall Deficits Through the Water Cycle Using Earth Observation Datasets: A Case Study in Senegal

Abstract

Rainfall deficits that develop into socio-economic droughts have triggered major humanitarian crises in recent years, and are expected to become even more frequent as a result of climate change. Earth observation methods are very useful for drought hazard assessment as they are available globally at high spatiotemporal resolutions. In this study, we analyze the potential to track rainfall deficits through the water cycle using satellite-based datasets, with a focus on the added value of satellite-derived soil moisture (SM). For the country of Senegal in the western Sahel, we show that SM closes the gap between rainfall deficits and negative impacts on vegetation, and that including SM in drought hazard assessment allows for an early warning of a developing food crisis. These findings support the development of novel drought risk financing mechanisms, which are much faster than traditional indemnity-based models.