Remote sensing based water stress dynamics monitoring and drought impact prediction

Climate change impacts on Earth’s ecosystems have become increasingly evident in recent years. Europe is currently the fastest-warming continent, with temperatures rising at approximately twice the global average rate. Climatic extremes, rising temperatures, and altered precipitation patterns are expected to increase the frequency and severity of droughts, especially in southern Europe. Vegetation is particularly sensitive to climatic conditions; consequently, substantial impacts of climate change on vegetation are expected in the future. 

In the presented study, a novel product is developed that combines near-real-time Earth observation data with short- to medium-range weather forecasts to monitor water stress dynamics and anticipate drought impacts. Earth observation data and derived products are utilized to deliver a regular monitoring of water stress and drought conditions. The application is based on a Combined Drought Indicator (CDI) approach, which enables the differentiation of drought severity levels. The CDI is based on anomaly detection using Copernicus Sentinel-2 and Sentinel-3–derived Normalized Difference Vegetation Index (NDVI), Sentinel-3–derived Land Surface Temperature (LST), Surface Soil Moisture (SSM) from the Copernicus Land Monitoring Service (CLMS), and the Standardized Precipitation Index (SPI) derived from Climate Hazards Center Infrared Precipitation with Stations (CHIRPS) data. Short-range to seasonal forecasts are integrated using the ECMWF HRES product. This information is exploited to generate spatially explicit early warnings of potential drought impacts. The derived product is computed at five-day intervals. To assess the accuracy of the product, forecasts for recent past years are generated and evaluated against existing drought maps and agricultural datasets. 

The presented approach moves beyond classical drought indices by focusing on drought impacts, such as agricultural stress, water availability and hydrological deficits. The resulting product can assist in anticipating and managing drought impacts for stakeholders from agriculture, water management, civil protection, and other drought-affected areas.