Super Drought: An Innovative Framework for Understanding Compound Drought Risk with Online Monitoring Platform

    Different types of drought, characterized by their distinct temporal scales, often interact in complex ways and pose significant challenges for drought risk assessment and management. This study introduces the innovative concept of "super drought", which refers to the simultaneous occurrence of extreme droughts across multiple time scales, advancing our understanding of compound drought risks. We demonstrate that super drought represents a unique phenomenon where meteorological, agricultural, and hydrological droughts coincide, leading to more severe impacts than when these events occur in isolation.

    To quantify super drought, we developed the Comprehensive Multiscalar Index (CMI) based on a vine copula framework. This novel approach overcomes the limitations of traditional drought indices by probabilistically integrating drought conditions across multiple time scales (3-, 6-, 12-, 24-, and 48-month). The CMI was validated against GRACE satellite-based total water storage observations, showing significantly improved performance in capturing overall water deficits compared to conventional indices.

    To support operational drought monitoring and research, we developed superdrought.com as the first online platform dedicated to global super drought assessment. The platform provides: (1) near-real-time global monitoring at 0.5° resolution, (2) interactive visualization tools with customizable temporal and spatial analysis capabilities, and (3) free access to historical CMI datasets from 1961 to present. This comprehensive system enables users to track the evolution of compound drought events and assess their spatial patterns and temporal dynamics.

    This integrated framework of concept, methodology, and operational platform represents a significant advancement in drought risk assessment. By highlighting that the most devastating droughts often result from the synchronization of water deficits across multiple components of the hydrological cycle, our approach provides new insights for drought risk assessment and early warning systems, emphasizing the need for integrated approaches in drought monitoring and management.