基于强度-持续时间-面积的干旱相似性研究

Drought similarity analysis based on intensity-duration-area characteristics

摘要

【目的】干旱具有发生缓慢，影响范围广等特点，对水资源、农业、能源等造成严重威胁。气候变化导致干旱发生更为频繁，因此有必要加强干旱灾害的评估研究，基于历史案例的相似分析是干旱灾害评估的重要手段。【方法】基于干旱强度、持续时间以及影响面积特征，以1980—2021年云南省逐日降水与逐月气温数据为基础，提出了一种干旱相似性的评估方法。首先基于游程理论分析云南省历史典型干旱事件的强度、持续时间与覆盖面积等特征。其次，选取2019年干旱事件为典型案例评估该事件的演变过程。最后计算2019年干旱与历史极端干旱事件不同特征之间的距离，并进行相似性评估。【结果】对2019年干旱事件进行相似性分析，通过与识别的相似干旱事件进行空间对比，表明识别的干旱事件强度-持续时间-面积的相似度较高(相似度超过80%)。【结论】提出的干旱相似性分析方法综合了干旱事件的强度、持续时间和覆盖面积特征，可以较为准确地识别相似的干旱事件，可为干旱灾情评估等防旱抗旱工作提供技术支持。

Abstract

[Objective] Droughts are characterized by their slow onset and widespread impacts, posing significant threats to water resources, agriculture, and energy. Climate change has increased the frequency of droughts and thus it is important to deepen our understanding of drought impact assessment, for which the similarity analysis of droughts based on historical events is a useful tool. [Methods] Based on daily precipitation and monthly temperature data from ERA5 in Yunnan Province for the period 1980—2021, this study analyzes drought intensity, duration, and coverage area, and proposes a method for drought similarity analysis. Firstly, the run theory is employed to analyze the intensity, duration, and coverage area of historical droughts. Secondly, the 2019 drought event is selected as the case study to evaluate its evolutionary process. Finally, the distances of different characteristics between the 2019 drought event and other historical droughts in Yunnan Province are calculated for similarity assessment. [Results] By conducting the similarity assessment of the 2019 drought event and comparing the spatial variability, results show that the similarity between the targeted drought event and identified drought events is high(with a similarity measure of over 80%). [Conclusion] The drought similarity assessment method proposed in this study combines intensity, duration, and coverage area of drought events and performs well in identifying similar drought events, which can provide technical support for drought disaster assessment.

关键词

干旱 / 干旱特征 / 相似性 / 云南省 / 气候变化 / 时空变化 / 降水 / 水资源

Key words

drought / drought characteristics / similarity / Yunnan / climate change / spatiotemporal changes / precipitation / water resource

基金资助

国家自然科学基金项目(42271024)