毛乌素沙地2002—2021年多尺度干旱特征（英文）

Multi-scale drought characteristics in Mu Us Sandy Land from 2002 to 2021

摘要

【目的】全球变暖导致自然灾害频发，为探究毛乌素沙地干旱的时空演变规律，【方法】基于2002—2021年高分辨率气象数据,采用正常降水百分率(PNP)、经验正交函数(EOF)、M-K检验及小波分析等方法,从多时间尺度分析该地区干旱的时空特征。【结果】结果表明:(1)除月尺度干旱趋势不显著外,其余时间尺度均呈显著减缓趋势,且长时间尺度的趋势更为明显;(2)干旱空间上呈中心放射状分布,中心区域干旱更严重、响应更敏感,短时间尺度干旱波动剧烈、干湿交替频繁,而长时间尺度干旱持续性强、波动趋缓;(3)PNP在短时间尺度检测到更多极端干旱事件,其周期性变化不规则;长时间尺度干旱持续时间长、周期更稳定,且在2011年前后发生显著变化。【结论】研究揭示了毛乌素沙地干旱的多尺度特征,可为不同时间尺度干旱指标的评价与应用、区域干旱监测及防灾措施的制定提供科学依据。

Abstract

[Objective] Global warming has led to frequent natural disasters. The spatiotemporal evolution patterns of drought in the Mu Us Sandy Land(MUSL) are investigated. [Methods] Based on high-resolution meteorological data from 2002 to 2021, multiple method were employed, including percent of normal precipitation(PNP), empirical orthogonal function(EOF), Mann-Kendall(M-K) test, and wavelet analysis, to analyze the spatiotemporal characteristics of drought in this region across multiple time scales. [Results] The result showed that:(1) except for the monthly scale, where the drought trend was insignificant, all other time scales showed a significant alleviating trend, which was more pronounced at longer time scales.(2) Drought was spatially distributed in a central radiating pattern, with the central area experiencing more severe drought and being more sensitive to responses. Short-term droughts were characterized by intense fluctuations and frequent wet-dry transitions, while long-term droughts persisted for extended durations with weaker fluctuations.(3) PNP detected more extreme drought events at short-term time scales, exhibiting irregular periodic changes. In contrast, droughts at long-term time scales persisted for extended durations with more stable cycles, and showed significant changes around 2011. [Conclusion] These findings reveal the multi-scale characteristics of drought in the MUSL, which can provide a scientific basis for the evaluation and application of drought indicators at different time scales, regional drought monitoring, and the formulation of disaster prevention measures.

关键词

干旱时空特征 / 经验正交函数 / M-K检验 / Morlet小波分析 / 毛乌素沙地 / 多时间尺度 / 干旱区半干旱区 / 影响因素

Key words

spatiotemporal characteristics of drought / empirical orthogonal function / Mann-Kendall test / Morlet wavelet analysis / Mu Us Sandy Land / multi-temporal scales / arid and semi-arid regions / influencing factors

基金资助

国家自然科学基金项目(42302309)

延安大学博士科研启动项目(YDBK2017-19)