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

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.

Keywords

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

Funding

National Natural Science Foundation of China(42302309)

Yan’ an University Doctoral Research Startup Project(YDBK2017-19)