1961—2023年中国降雨侵蚀力变化特征及未来趋势预估

    Characteristics of rainfall erosivity change during 1961-2023 and its trend projection of future in China

    • 摘要: 为水土流失预防和科学治理提供参考,基于1961—2023年中国均一化逐日降水资料对降雨侵蚀力进行估算,并结合侵蚀性降雨特征开展降雨侵蚀力变化趋势和成因分析,并探讨降雨侵蚀力的极端变化,在此基础上,摸清中国及十大流域降雨侵蚀力变化危险状况,并基于Hurst方法预估未来变化趋势。结果表明:1)1961—2023年,中国及东南诸河、西北诸河流域年降雨侵蚀力呈现显著增加趋势,西南诸河流域则呈现显著减少趋势,其余大多数流域增加趋势不明显;2)中国及十大流域大多年侵蚀性降雨量、雨日、平均降雨强度增加,其中平均降雨强度和/或降雨量的变化为大多数流域年降雨侵蚀力变化的主要成因;3)中国大部地区年最大日降雨侵蚀力增加,10年一遇次降雨侵蚀力1961—2023年相比1961—1990年呈增加的站点比例多达64.3%;4)近60年来,中国大部地区降雨侵蚀力变化具有危险性,站点比例达80%,其中降雨侵蚀力总量及极端都呈增加变化的类型在各流域均最为突出、范围最大;5)除西南诸河流域外,预估大多数流域年降雨侵蚀力未来变化趋势将均以持续增加为主。目前和未来气候条件对中国水土流失治理不容乐观,需根据降雨侵蚀力变化特点,因地制宜制定长期规划和采取有效措施。

       

      Abstract: This study aims to estimate the variation characteristics of rainfall erosivity in 10 river basins in China. The daily precipitation data was then selected from 1961 to 2023. Three characteristic values of erosive rainfall were combined, such as the total erosive rainfall, erosive rainy days, and mean erosive rainfall intensity. The trend and cause of annual rainfall erosivity were analyzed by the linear regression and Spearman’s rank partial correlation analysis. The extreme variations were obtained from the trend of annual maximum daily rainfall erosivity and difference of event rainfall erosivity under a 10-year return period during the two periods 1961-2023 and 1961-1990. The recurrence period was statistically fitted for the goodness of fit using the Generalized extreme value distribution (GEV) function and Kolmogorov-Smirnov method. Then, the dangerous situations of rainfall erosivity were comprehensively determined to consider the overall trends and extreme variations in China. At last, the annual rainfall erosivity was predicted using the Hurst index by rescaled range analysis P/S. Some recommendations were given on soil erosion prevention and control in different key erosion regions. The results show that: 1) The ever-increasing trend was found in the annual rainfall erosivity in the Southeast- and Northwest-river basin from 1961 to 2023. But the Southwest-river basin showed a significant decreasing trend. There was no outstanding increasing trend in most other river basins; 2) The positive rate of change was observed in the annual erosive rainfall, rainy days, and mean erosive rainfall intensity in most river basins. Particularly, the significantly increasing trend was found in the mean erosive rainfall intensity in the Yellow, Yangtze, southeast, Pearl, and northwest river basins. The different causes contributed to the trends of annual rainfall erosivity in the 10 river basins. The annual mean intensity of erosive rainfall and/or rainfall was dominated by the trend of annual rainfall erosivity in most river basins. 3) A positive rate of change was found in the maximum daily rainfall erosivity in most parts of China. The number of stations with the extreme maximum historical value was increasing over time, with the peak in the 2010s over that in the 1990s. The ratio of stations with the increasing event rainfall erosivity under a 10-year return period between the two periods 1961-2023 and 1961-1990 to the total was 64.3%; 4) Either the total amount or the extreme of rainfall erosivity was damaged to the soil and water conservation. The rainfall erosivity showed a proportion of 80% of total stations in most parts of the country over the past 60 years. Among them, both the total and extreme rainfall erosivity were the most prominent and widespread in all river basins; 5) The annual rainfall erosivity in most stations in most 10 river basins was predicted to continue the ever-increasing trends during 1961-2023, except for Southwest river basin with ever decreasing trend. The current and future climate conditions are not optimistic for soil erosion control in China. It is very necessary for long-term plans and effective measures, according to the total amount and extreme changes of rainfall erosivity in specific regions. The findings can also provide scientific references for the prevention and control of soil erosion.

       

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