基于综合干旱指数的吐鲁番地区干旱时空演变特征与风险分析OA

To address the limitations of using a single drought index to capture comprehensive drought events,this study focuses on the extremely arid Turpan Basin.It integrates meteorological(standardized precipitation evapotranspiration index[SPEI]),hydrological(standardized runoff index[SRI]),agricultural(standardized soil moisture index[SSMI]),and ecological(vegetation condition index[VCI])drought indices,incorporating opti-mal combination weights and the theory of multivariate joint distribution(Copula function)into the framework for constructing a comprehensive drought index.Two comprehensive drought indices,the multivariate compre-hensive drought index(MCDI)and the optimal copula-based drought index(OCDI),were constructed.Based on a suitability comparison,the spatiotemporal dynamics and risk patterns of drought in the study area from 1982 to 2022 were further revealed.The results show the following:(1)Both the MCDI and OCDI are suitable for drought monitoring,with the OCDI based on the copula function performing best in terms of drought identifica-tion consistency,response sensitivity,and spatial characterization capability.(2)Comprehensive drought in the study area generally showed a continuous intensifying trend,with particularly severe conditions after 2008.Sea-sonally,droughts occurred frequently in spring and autumn but eased in summer and winter.In the human-activi-ty-intensive central and northern regions,droughts exhibited low-frequency,long-duration,high-intensity charac-teristics,whereas the southeastern desert area was mainly characterized by high-frequency,short-duration,medi-um-to-low-intensity droughts.(3)Drought risk showed a phased increasing trend,with a spatial pattern of increas-ing risk from northwest to southeast.Regional drought risk exhibited strong persistence,with probabilities ex-ceeding 65%for each grade of drought risk remaining unchanged over two consecutive years.These results pro-vide an effective method for comprehensive drought monitoring and dynamic risk assessment in the Turpan re-gion and hold considerable scientific importance for deepening the understanding of drought evolution patterns in extremely arid areas and formulating regional drought mitigation strategies.