Understanding the propagation processes and driving mechanisms of meteorological, hydrological, and agricultural droughts in Xinjiang

Drought propagation among meteorological, hydrological, and agricultural systems poses significant challenges to water security and agricultural sustainability in arid regions. This study investigated the propagation mechanisms and driving factors of multi-type droughts in Xinjiang, China, using ERA5-Land reanalysis data (1990–2024) to derive the standardized precipitation index (SPI), standardized runoff index (SRI), and standardized soil moisture index (SSI). Wavelet coherence analysis (WTC), maximum Pearson correlation coefficient (MPCC), Copula-based modeling, and SHAP analysis were integrated to identify drought propagation pathways, response thresholds, and dominant drivers. Results showed that drought variability decreased with increasing timescales, whereas SSI exhibited stronger persistence, and the coherence among drought types strengthened at medium- and long-term scales. Agricultural drought responded to meteorological drought with an average lag of approximately 4 months, while hydrological drought exhibited delays of 3–7 months, with agricultural-to-hydrological drought propagation occurring after 2–3 months. Propagation thresholds ranged from −1.00 to −1.97 for meteorological-to-hydrological drought, −1.07 to −2.28 for meteorological-to-agricultural drought, and − 1.04 to −2.32 for agricultural-to-hydrological drought. Soil moisture emerged as a key regulator of drought evolution, while precipitation availability, runoff processes, and hydrothermal conditions jointly controlled drought variability and propagation. These findings provide a scientific basis for drought monitoring, early warning, and adaptive water resource management under climate change, supporting agricultural drought mitigation and regional disaster risk reduction. Practical implications This research systematically elucidates the propagation patterns, critical thresholds, and driving mechanisms of drought across meteorological, hydrological, and agricultural systems. Its core practical value lies in translating complex scientific insights into actionable decision-making tools and management frameworks for drought risk prevention and control. By establishing a tiered early-warning, zoned-response, and targeted-intervention system, it can effectively enhance the proactiveness of drought disaster response, thereby safeguarding regional ecological security and agricultural sustainability. Based on the probability thresholds identified in this research, a dynamic and tiered drought early-warning and risk management mechanism can be developed. Specifically, when the regional Standardized Precipitation Index (SPI) decreases to approximately −1.00, a preliminary warning can be triggered, alerting the agricultural sector to enhance soil moisture monitoring and coordinate irrigation resources. A further decline in SPI below −2.28 indicates a significantly elevated risk of agricultural drought, necessitating the activation of emergency response plans. These plans include actions such as water resource reallocation and water-use quota management, thereby achieving refined and forward-looking drought management. Given the significant spatial heterogeneity in drought propagation speed, differentiated management strategies tailored to specific zones and timescales should be implemented. In southern Xinjiang, drought propagates rapidly, and the system's buffering capacity is limited. Therefore, the management focus should be on enhancing real-time monitoring capabilities and strengthening the speed of emergency response. In northern Xinjiang, propagation exhibits a longer lag time. Management should, therefore, emphasize mid- to long-term optimization of water resource allocation and the large-scale adoption of water-saving agricultural technologies. On the temporal dimension, prevention and control strategies must also vary according to the timescale. At short timescales, the focus should be on the coupled early warning of meteorological and hydrological droughts. Leveraging the response relationship between the Standardized Precipitation Index (SPI) and the Standardized Runoff Index (SRI), an early-warning model based on multi-scale coherence can be developed. This model aids in pre-identifying the risk of abrupt transitions between drought and flood. Particular vigilance is required in the mountainous areas of northern Xinjiang against secondary disasters, such as flash floods and landslides, potentially triggered by short-duration heavy rainfall following prolonged drought periods. At medium- to long-term scales, efforts must be directed toward soil moisture regulation. Considering the dependence of the Standardized Soil Moisture Index (SSI) on soil moisture, water-saving and moisture-conserving technologies, such as drip irrigation and plastic film mulching, should be promoted. These practices help reduce inefficient dissipation of soil water and enhance the drought resilience of farming systems. In summary, by delineating the key processes of drought propagation, this research provides a scientific basis and a technical pathway for Xinjiang to construct a drought prevention and control system and a sustainable water resource governance model. This contribution aids in enhancing the resilience of regional food security, ecological security, and socio-economic stability in the context of climate change.