| 高峡,雷双舟,冯杰.基于Copula模型的前期干旱对极端高温影响的定量风险研究[J].干旱地区农业研究,2026,(4):282~290 |
| 基于Copula模型的前期干旱对极端高温影响的定量风险研究 |
| Quantitative risk assessment of the impact of antecedent drought on extreme high temperatures based on Copula model |
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| DOI：10.7606/j.issn.1000-7601.2026.04.27 |
| 中文关键词: 前期干旱 极端高温 Copula模型 条件概率 定量风险评估 |
| 英文关键词:antecedent drought high temperature event Copula model conditional probability quantitative risk assessment |
| 基金项目:四川省自然科学基金面上项目（62850221） |
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| 中文摘要: |
| 为定量分析四川省不同前期干旱条件下极端高温的发生风险，基于1962—2022年CN05.1格点气象数据集，采用多时间尺度标准化降水蒸散指数（SPEI）表征前期干湿状态，构建一种基于Copula函数的极端高温和前期干旱联合建模框架，明确极端高温与6个月尺度下标准化降水蒸散指数（SPEI-6）的依赖结构，并采用条件概率分布方法，系统评估前期不同干湿条件对极端温度的超越概率及重现期的影响。结果表明：Gaussian Copula函数和旋转90°Clayton Copula函数为最优模型，占比分别达到22.62%和20.67%；前期干旱显著提高极端高温风险，四川省东北和西南大部分区域，前期干旱条件下极端温度超过高阈值的风险显著高于湿润条件，其中干旱条件（SPEI-6≤-0.5）与湿润（SPEI-6>0.5）条件下极端高温概率差值达0.2~0.3，极端干湿条件下差值达0.35~0.45。同时，前期干旱情景下极端温度的条件重现期较传统单变量重现期缩短8~25 a，川东地区表现最显著。研究结果可为四川省复合型高温干旱风险研判与防灾减灾提供数据支撑。 |
| 英文摘要: |
| To quantitatively analyze the occurrence risk of extreme high temperatures under different antecedent drought conditions in Sichuan Province, this study utilized multi-temporal-scale gridded meteorological data from CN05.1 spanning 1962-2022. The standardized precipitation evapotranspiration index (SPEI) was employed to characterize antecedent dry-wet conditions. A joint modeling framework for extreme high temperatures and antecedent drought was constructed based on Copula functions, elucidating the dependence structure between extreme high temperatures and the 6-month SPEI (SPEI-6). A conditional probability distribution approach was then adopted to systematically assess the impact of different antecedent dry-wet conditions on the exceedance probability of extreme temperature thresholds. The results indicate that the Gaussian Copula and the 90°-rotated Clayton Copula were identified as the optimal models, accounting for 22.62% and 20.67% of the total grid cells, respectively. Antecedent drought significantly elevated the risk of extreme high temperatures. In most areas of northeastern and southwestern Sichuan, the risk of extreme temperatures exceeding high thresholds under antecedent drought conditions was substantially higher than under wet conditions. Specifically, the probability difference in extreme high temperatures between drought conditions (SPEI-6≤-0.5) and wet conditions (SPEI-6>0.5) ranged from 0.2 to 0.3, and this difference increased to 0.35-0.45 under extreme dry versus extreme wet conditions. Furthermore, the conditional return periods of extreme temperatures under antecedent drought scenarios were shortened by 8 to 25 years compared to traditional univariate return periods, with the most pronounced reductions observed in eastern Sichuan. These findings provide critical data support for risk assessment and disaster prevention and mitigation strategies concerning compound hot-drought events in Sichuan Province. |
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