基于CMIP6多模式的黄河流域降雨侵蚀力未来变化预估

Projecting changes in rainfall erosivity in the Yellow River Basin based on CMIP6 models

  • 摘要: 土壤侵蚀是黄河流域生态保护和高质量发展面临的挑战之一, 而降雨侵蚀力则是驱动土壤侵蚀的关键因素。量化未来降雨侵蚀力的时空变化对评估潜在的土壤侵蚀风险具有重要意义。本文基于第六次国际耦合模式比较计划(CMIP6)中5个全球气候模式降水数据, 采用日降雨侵蚀力模型预估了SSP1-2.6 (低排放)和SSP5-8.5 (高排放)情景下, 近未来(2021—2060年)与远未来(2061—2100年)时期黄河流域降雨侵蚀力的时空变化特征, 分析了年侵蚀性降雨日数和强度的变化。结果表明: 1)未来时期, 低排放和高排放情景下黄河流域降雨侵蚀力均呈增加趋势, 且高排放情景下的增幅更大。与基准期(1971—2010年)相比, 近未来时期两种情景下流域多年平均年降雨侵蚀力将分别增加11.50%和15.21%; 至远未来时期, 其增幅将进一步升高, 分别达17.20%和33.32%。2)未来时期多年平均年侵蚀性降雨日数和强度均较基准期增加。在高排放情景远未来时期, 多年平均年侵蚀性降雨日数和强度增幅最大, 分别达27.55%和4.71%。季节性分析表明, 未来时期春季和冬季的降雨侵蚀力变化较大, 应当予以关注。3)与高排放情景相比, 低排放情景能够有效减缓黄河流域未来降雨侵蚀力的增加。近未来和远未来时期, 分别可避免2.88%和17.51%的增长。实施低排放策略可以有效缓解年侵蚀性降雨日数和强度增加, 降低黄河流域未来面临的土壤侵蚀风险。

     

    Abstract: The Yellow River Basin, a crucial agricultural and ecological region in China, features diverse landforms and a relatively fragile environment. It plays an essential role in ensuring national food and ecological security. However, soil erosion not only undermines cropland productivity but also poses a significant threat to soil and water conservation as well as overall ecological stability. In the context of global climate change, the frequency and intensity of extreme precipitation events are projected to continue increasing, thereby altering the spatiotemporal patterns of future rainfall erosivity and exerting profound impacts on regional soil erosion processes. Therefore, accurately quantifying the spatiotemporal variations of future rainfall erosivity is of great significance for scientifically assessing potential soil erosion risks. This study is based on five Coupled Model Intercomparison Project Phase 6 (CMIP6) precipitation datasets and employs a daily rainfall erosivity model to project changes in rainfall erosivity in the Yellow River Basin for the near future (2021–2060) and the far future (2061–2100. The changes in annual erosive rainfall days and intensity are also analyzed. Compared with single-model simulations, using a multi-model ensemble can effectively reduce uncertainties in climate projections and improve the robustness of the results. Therefore, this study adopts the ensemble mean of five CMIP6 models as the future dataset. The results indicate that 1) under both future emission scenarios, rainfall erosivity exhibits an overall increasing trend in the Yellow River Basin, with a more pronounced rise under the high-emission scenario. Compared to the baseline period, multi-year mean annual rainfall erosivity is projected to increase by 11.50% and 15.21% in the near future under the low-emission and high-emission scenarios, respectively, and by 17.20% and 33.32% in the far future. 2) In future periods, the multi-year mean annual number of erosive rainfall days and intensity both increase relative to the baseline period, with the largest increases occurring in the far future under the high-emission scenario, reaching 27.55% and 4.71%, respectively. Seasonal analysis reveals that the changes in rainfall erosivity are particularly pronounced in spring and winter, which warrants attention in the future. 3) Compared to the high-emission scenario, the low-emission scenario can effectively mitigate the increase in rainfall erosivity, reducing the projected rise by 2.88% and 17.51% in the near future and far future, respectively. The implementation of low-emission strategies can help curb the future increase in both the frequency and intensity of annual erosive rainfall, thereby reducing the potential soil erosion risk in the Yellow River Basin.

     

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