Droughtmap-ASB: An Integrated Earth Observation–Based Drought Monitoring and Decision Support System for Water and Environmental Management in Central Asia

Central Asia is highly vulnerable to increasing drought frequency and intensity due to climate change, strong dependence on irrigated agriculture, and complex transboundary water systems. Effective drought risk management in the Aral Sea Basin (ASB), therefore, requires timely, spatially explicit, and policy-relevant information that can be accessed and interpreted by water managers, environmental experts, and hydrometeorological services. In this study, we present Droughtmap-ASB, an operational, Earth observation–based drought monitoring and decision support tool designed to support drought assessment, near real time warning, and policy-relevant planning across multiple spatial and temporal scales.

Droughtmap-ASB integrates satellite-derived vegetation and evaporative stress indicators with climate reanalysis data to provide a comprehensive characterization of agricultural and meteorological drought. The core framework combines Sentinel-3–based NDVI and land surface temperature-dependent Evaporative Stress Index (ESI) with a dynamic ten-year baseline to compute a Drought Severity Index (DSI), capturing drought onset, duration, and intensity. In addition, the system implements SPI, SPEI, and the Hydrothermal Coefficient (HTC) derived from ERA5 reanalysis data, enabling consistent assessment of meteorological drought conditions. Drought conditions are classified into eight standardized drought classes ranging from initial mild to long-term severe drought.

A key strength of Droughtmap-ASB is its multi-scale spatial design, which allows analyses at resolutions of 5 × 5 km grids up to rayon, oblast, national, and basin-wide levels, ensuring compatibility with both operational water management and policy frameworks. The web-based dashboard provides interactive visualization, while an automated bulletin module generates bi-weekly, monthly, and seasonal drought reports, supporting routine information dissemination for end-users.

By translating complex Earth observation data into actionable indicators, standardized drought classes, and policy-ready bulletins, Droughtmap-ASB bridges the gap between scientific monitoring and decision-making. The tool supports evidence-based water allocation, agricultural risk management, and climate adaptation planning, contributing to improved drought preparedness and resilience in Central Asia.

Keywords: Agricultural drought; Meteorological drought; Web-based drought monitoring; Earth observation data; Drought bulletins; Central Asia