Effects of climate warming on debris flow activity and sediment supply in high mountain regions.

在副冰川循环(即描述冰川消融后沉积物通量演变的理论模型)的框架下，该项目希望分析持续的气候变暖对沉积物供应和山区集水区泥石流事件发生的影响。以往关于这些主题的研究表明，气候在山区盆地的地表过程、动力学和泥沙迁移中起着至关重要的作用。然而，山区集水区对现代气候变化的不同反应表明，除了冰融化后水量和泥沙有效性的增加外，其他一些参数可能控制泥沙产生和泥沙转移的动力学。最近的研究表明，在这方面，河流良好的连通性和平衡的运输能力可能是关键。然而，针对气候变暖，在山区盆地的沉积物层叠中研究这些方面的研究仍然很少。在这个项目中，我建议分析意大利阿尔卑斯山的两个小山谷，以努力了解山区集水区对气候变暖的反应，并评估冰川融化、永久冻土退化和极端降水增加对沉积物供应和泥石流活动的作用。为了实现这些目标，我建议结合不同的技术，分析：1)利用宇宙成因核素技术分析山地盆地泥沙运动动力学的变化；2)通过树枝年代学测定泥石流事件的年代学；3)通过正射影像的时间序列分析来确定泥石流和岩崩起始区的位置。通过分析不同形态的盆地，我将能够框定当地参数(如地形、植被和连通性)在山区集水区泥沙运移动力学中的影响。这种方法将使我能够探索温度和极端降水量增加对冰川盆地和去冰川盆地的影响，并评估它们对沉积物释放和输送的影响。通过结合这些不同的技术，我将涵盖不同的时间尺度，将现有信息(即自然灾害事件数据库)与过去的新数据结合起来，并使用它们来探索未来可能出现的情景。预计项目成果将使我们在了解气候如何调节山区集水区的地表过程方面向前迈进一步。这些成果的相关性不仅限于科学界，而且预计对地方和地区当局也具有重要意义，它们可以利用项目成果来减少山区的脆弱性，并为高山环境制定可持续管理计划。

In the framework of the paraglacial cycle (i.e., the theoretical model that describes the sediment flux evolution after deglaciation), this project wants to analyze the effects that the ongoing climate warming has on the sediment supply and on the occurrence of debris-flow events in mountain catchments. Previous studies on these topics indicate that climate plays a crucial role in the surface processes dynamics and sediment transfer in mountain basins. However, the different response of mountain catchments to the modern climate-change suggests that some other parameter, in addition to the increase in water discharge and sediment availability that follows the melting of ice, may control the dynamics of sediment production and sediment transfer. Recent studies have suggested that a good connectivity and a balanced transport capacity of the rivers may be pivotal in this context. However, studies that investigate these aspects within the sediment cascade of mountain basins and in light of climate warming remain scarce. In this project, I propose to analyze two small valleys of the Italian Alps in the effort to understand the response of mountain catchments to climate warming and assess the role that glacial melting, permafrost degradation, and increased extreme precipitation may have on sediment supply and debris-flow activity. To reach these goals, I propose to combine different techniques and analyze: 1) the variations in the sediment transport dynamics of mountain basins by means of cosmogenic nuclides techniques; 2) the chronology of debris-flow events through dendrochronology dating; and 3) the location of debris flows and rock falls initiation areas by the time-series analysis of orthophotos. By analyzing basins with different morphologies, I will be able to frame the effects of local parameters (such as morphology, vegetation, and connectivity) in the sediment transport dynamics of mountain catchments. This approach will allow me to explore the effect of temperature and extreme precipitation increase on both glaciated and deglaciated basins, and to assess their influence on the release and transport of sediment. By combining these different techniques I will cover different timescales, integrating existing information (i.e., database of natural hazard events) with new data on the past, and using them to explore possible future scenarios. The project outcomes are expected to bring us one step forward in the understanding of how climate may modulate surface processes in mountain catchments. The relevance of these results is not limited to the scientific community, but is expected to be of primary importance also for local and regional authorities, who may use the project’s outcomes to reduce the vulnerability of mountain regions and develop sustainable management plans for Alpine environments.