Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Environ Res Public Health. 2021 Oct 21;18(21):11054. doi: 10.3390/ijerph182111054.
Soil erosion is a serious ecological problem in the fragile ecological environment of the Tibetan Plateau (TP). Rainfall erosivity is one of the most important factors controlling soil erosion and is associated with the El Niño southern oscillation (ENSO). However, there is a lack of studies related to the spatial distribution and temporal trends of rainfall erosivity on the TP as a whole. Additionally, the understanding of the general influence of ENSO on rainfall erosivity across the TP remains to be developed. In this study, long-term (1971-2020) daily precipitation data from 91 meteorological stations were selected to calculate rainfall erosivity. The analysis combines co-kriging interpolation, Sen's slope estimator, and the Mann-Kendall trend test to investigate the spatiotemporal patten of rainfall erosivity across the TP. The Oceanic Niño Index (ONI) and multivariate ENSO Index (MEI) were chosen as ENSO phenomenon characterization indices, and the relationship between ENSO and rainfall erosivity was explored by employing a continuous wavelet transform. The results showed that an increasing trend in annual rainfall erosivity was detected on the TP from 1971 to 2020. The seasonal and monthly rainfall erosivity was highly uneven, with the summer erosivity accounting for 60.36%. The heterogeneous spatial distribution of rainfall erosivity was observed with an increasing trend from southeast to northwest. At the regional level, rainfall erosivity in the southeastern TP was mainly featured by a slow increase, while in the northwest was more destabilizing and mostly showed no significant trend. The rainfall erosivity on the whole TP was relatively high during non-ENSO periods and relatively low during El Niño/La Niña periods. It is worth noting that rainfall erosivity in the northwest TP appears to be more serious during the La Niña event. Furthermore, there were obvious resonance cycles between the rainfall erosivity and ENSO in different regions of the plateau, but the cycles had pronounced discrepancies in the occurrence time, direction of action and intensity. These findings contribute to providing references for soil erosion control on the TP and the formulation of future soil conservation strategies.
土壤侵蚀是青藏高原脆弱生态环境中的一个严重生态问题。降雨侵蚀力是控制土壤侵蚀的最重要因素之一，与厄尔尼诺南方涛动（ENSO）有关。然而，目前缺乏对整个青藏高原降雨侵蚀力的空间分布和时间趋势的研究。此外，对 ENSO 对青藏高原降雨侵蚀力的普遍影响的理解仍有待发展。在这项研究中，选择了 91 个气象站的长期（1971-2020 年）日降水数据来计算降雨侵蚀力。分析结合协同克里金插值、森斜率估计器和曼恩-肯德尔趋势检验，研究了青藏高原降雨侵蚀力的时空格局。选择海洋尼诺指数（ONI）和多变量厄尔尼诺指数（MEI）作为 ENSO 现象特征化指数，通过连续小波变换探讨了 ENSO 与降雨侵蚀力的关系。结果表明，从 1971 年到 2020 年，青藏高原的年降雨侵蚀力呈上升趋势。季节性和月度降雨侵蚀力极不均匀，夏季侵蚀力占 60.36%。降雨侵蚀力的空间分布不均匀，从东南向西北呈递增趋势。在区域水平上，青藏高原东南部的降雨侵蚀力主要呈缓慢增加趋势，而西北部则更加不稳定，大部分呈无显著趋势。整个青藏高原在非 ENSO 期间的降雨侵蚀力较高，而在厄尔尼诺/拉尼娜期间则较低。值得注意的是，在拉尼娜事件期间，青藏高原西北部的降雨侵蚀力似乎更为严重。此外，高原不同地区的降雨侵蚀力与 ENSO 之间存在明显的共振周期，但在发生时间、作用方向和强度上存在明显差异。这些发现为青藏高原的土壤侵蚀控制和未来的土壤保持策略的制定提供了参考。
