| 摘要: |
| 气候变化和水利工程运行显著改变了三峡库区水循环过程，近年来，库区干旱频发，分析其农业干旱的演变特征与驱动机制，解析现状防御条件下的因旱减产阈值，对于库区流域干旱的系统应对具有重要的意义。本研究首先基于标准化土壤湿度指数，分析库区流域1982-2022年农业干旱的时空演变特征，并识别其驱动要素；基于Copula理论计算干旱重现期，提取历史典型干旱场景，综合考虑蒸发、截留和径流等损失，引入作物生育期有效降雨量改进Jensen模型参数，提出一种基于改进的Jensen模型确定现状防御条件下、历史典型干旱重演的作物因旱减产阈值的计算方法。结果表明：1982-2022年间三峡库区农业干旱整体呈加剧趋势，且时空分异显著；其中，库尾区域为农业干旱的高发地带，库中游区域为长历时、大烈度、高峰值的重旱和特旱主要发生区域，库首区域为长历时极端干旱易发区。进一步研究发现，未来库区流域农业干旱总体呈减缓趋势。库区夏伏旱的关键驱动因子为降水，冬春连旱的直接影响因素为潜在蒸散发。在现状水利工程防御条下，库区流域发生2、5、10、20、50一遇的作物因旱减产率阈值为1.23%、5.12%、8.13%、15.44%、22.32%。研究成果可为库区抗旱水源配置、抗旱补水调度及补水方案推演提供技术支撑。 |
| 关键词: 农业干旱 标准化土壤湿度指数 改进的Jensen模型 作物因旱减产阈值 三峡库区 |
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| 基金项目:国家自然科学基金项目(52479018,52379069); 新疆维吾尔自治区重点研发计划项目(2023B02001-1); 湖北省水利工程学科111创新引智基地(三峡大学)联合资助） |
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| Evolution of Agricultural Drought and Drought-Induced Crop Yield Reduction Thresholds Under Current Mitigation Measures in the Three Gorges Reservoir area |
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常文娟,Li Bin,Li haiwen,Qu Yanping,Gan Zhiguo,Ma haibo,Liu Ji,Lin Qingxia
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China Three Gorges University
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| Abstract: |
| Climate change and the operation of hydraulic projects have significantly altered the water cycle in the Three Gorges Reservoir area. The Three Gorges Reservoir area has experienced recurrent seasonal droughts in recent years. Analyzing the evolution characteristics and driving mechanisms of seasonal agricultural drought in this? region, as well as coupled with the quantitative determination of yield reduction thresholds under current drought defense conditions, is significantly important for developing a systematic response to agricultural droughts. Firstly, the spatiotemporal evolution of seasonal agricultural drought in the reservoir area from 1982 to 2022 was investigated, based on the Standardized Soil Moisture Index (SSMI). Furthermore, additional analyses were conducted using Path Analysis to explore key driving factors. Additionally, drought return periods and representative drought years were determined using Copula theory, and historical typical drought scenarios are extracted. On this basis, effective rainfall was introduced to improve the parameters of the Jensen model, considering losses due to evaporation, interception, and runoff. A new method for calculating the drought-induced crop yield reduction thresholds under historical typical drought scenarios and current defense conditions was proposed based on the improved Jensen model. recurrence of historically typical drought. The results showed that agricultural droughts in the Three Gorges Reservoir area intensified between 1982 and 2022, with significant spatiotemporal variability. Specifically, the tail section of the reservoir was identified as the high-frequency agricultural drought-prone area, while the middle reaches were characterized by long-duration, high-intensity, and severe droughts. Similarly, the upper reaches were prone to extreme, long-duration droughts. Further analysis revealed that future agricultural droughts in the reservoir area were expected to decrease overall. The key driving factor for summer-fall droughts was precipitation, while potential evapotranspiration was the directly influenced factor for winter-spring consecutive droughts. Finally, under the current water conservancy defense conditions, drought-induced crop yield reduction thresholds for return periods of 2, 5, 10, 20, and 50 years were calculated as 1.23%, 5.12%, 8.13%, 15.44%, and 22.32%, respectively. Overall, these findings provided technical support for drought-resilient water resource planning, drought replenishment scheduling, and scenario-based water management in the Three Gorges Reservoir area. |
| Key words: Agricultural Drought Standardized Soil Moisture Index (SSMI) Improved Jensen model Drought-Induced Crop Yield Reduction Threshold Three Gorges Reservoir Area |
