| 摘要: |
| 【目的】解析气候变化下渭河流域干旱事件发生频率与强度以及时空演变趋势，预估未来区域干旱发生发展情势，为渭河流域未来旱灾防控和水安全保障提供参考依据。【方法】基于CMIP5统计降尺度数据集NEX GDDP中的CanESM2全球气候模式数据，采用象限转换校正方法实施校准，并利用游程分析等方法，从干旱指标标准化降水蒸散发指数（SPEI）与干旱事件特征的角度，分析渭河流域历史基准期（1966-2005年）与未来期（2021-2060年）2种排放情景（RCP4.5与RCP8.5）下的干旱时空演变特征，研究渭河流域干旱事件频率的空间特征与持续性变化。【结果】历史基准期与未来期SPEI在年际尺度下均呈下降趋势，其中RCP8.5情景下渭河流域春旱会显著加剧；未来干旱事件发生频率将呈现“两头减少，中间增多”的态势，即轻旱与特旱高频区域减少，中旱与重旱高频区域增多；流域尺度上，未来发生短历时干旱事件的频率有所减小，中长历时干旱事件频率增加，其中流域北部与渭河源头区的长持续性干旱事件发生频率会显著减小；未来不同间隔干旱事件的发生频率变化不大，依旧以1～6个月间隔的干旱事件为主，局地会有一定差异性。【结论】春季与冬季将是渭河流域未来干旱风险防范的重点季节，流域西部是冬旱防范的重点区域；未来轻旱与中旱仍是渭河流域最主要的干旱类型，但要警惕发生频率持续走高的中旱与重旱灾害所带来的风险；未来期流域中长历时干旱事件会有所增加，应采取应对措施减轻长持续性干旱事件给流域工农业生产带来的不利影响。 |
| 关键词: 干旱 NEX-GDDP CanESM2 SPEI 象限转换校正法 渭河流域 |
| DOI： |
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| 基金项目:国家自然科学基金项目(51979005)；陕西省自然科学基础研究计划项目(2020JM-250) |
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| Evolution characteristics of drought in the Weihe River Basin based on CanESM2 |
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DING Hao,ZHANG Hongbo,ZHANG Jingru,et al
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| Abstract: |
| 【Objective】The frequency,intensity and spatio-temporal variation of drought events in the Weihe River Basin under climate change were analyzed and the occurrence and development of future regional droughts were predicted to provide references for drought prevention and water security in future.【Method】This study selected the historical recorded data and modeled data from CanESM2 global climate model provided by the CMIP5 statistical downscaling dataset NEX-GDDP.The quadrant transformation method was employed to calibrate these data,and SPEI and the run theory were used to analyze the spatio temporal evolution characteristics of drought in historical period (1966-2005) and under two emission scenarios (RCP4.5 and RCP8.5) in future (2021-2060).Finally,the spatial and continuous variations of drought frequencies were discussed.【Result】SPEI in both periods showed a decreasing trend at annual scale.Spring droughts were significantly aggravated in the Weihe River Basin under RCP8.5 scenario.The occurrence frequencies of future droughts showed a trend of decreasing at ends and increasing in middle with reduction in light and extreme droughts and increase in medium and severe droughts.The frequencies of short duration drought events would decrease in future,while the frequencies of medium and long duration drought events would increase at watershed scale.The frequencies of long duration drought events in the northern part and the headwater region of the basin would decrease significantly.Drought events would remain the intervals of 1-6 months in future,with certain differences in some areas.【Conclusion】Spring and winter would be the critical periods for preventing drought risks in the Weihe River Basin and the western part would be the key areas for drought risk prevention in future.Light and medium droughts would still be the most important types of droughts,and attention should be paid to the potential disaster risks caused by medium and severe droughts.In addition,measures for reducing adverse effects of long-lasting drought events are suggested. |
| Key words: droughts NEX-GDDP CanESM2 SPEI quadrant transformation method Weihe River Basin |
