Water Rock Glaciers and climate change in the dry Andes of Bolivia: implications for future water supplies

玻利维亚干燥安第斯山脉的水岩冰川和气候变化：对未来供水的影响

• 批准号: NE/H018875/1
• 负责人: Stephan Harrison
• 金额: $ 8.91万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH018875%2F1
• 关键词: Water; Rock; Glaciers; climate; change

This project aims to investigate rock glaciers in the arid mountains of Bolivia and assess their future contribution to water supplies in the region. Mountain hydrology plays a crucial role in maintaining social and economic development in many arid regions of the world. However, climate change is leading to recession of mountain glaciers. In Bolivia mountain glaciers have undergone significant melting since the 1950s, and continued predicted warming over the 21st century will result in further glacier recession and eventual disappearance, especially where the glaciers are small. This glacier recession threatens the future water supplies for the cities of La Paz and El Alto, adversely affecting economic development and helping to drive social, political and ecological instability. However, in several of the high arid mountain regions in Bolivia considerable ice is enclosed within rock glaciers, elongate valley-bottom landforms comprising a variable mixture of rock debris and ice. These landforms are an important component of hydrological systems in many mountain systems, transporting large amounts of coarse and fine sediments to valley-bottom locations and forming extensive potential reservoirs of water. With a surface cover of rock debris, the ice content is insulated from low amplitude and high frequency temperature changes and, as a result, rock glaciers are predicted to respond more slowly than ice glaciers to climate warming. Consequently, they have the potential to play an important future role in hydrological systems under conditions of global warming, producing water supplies to mountain communities as glaciers undergo continued recession. Despite this, several obstacles stand in the way of a better understanding of the role that rock glaciers may be able to play in regulating mountain hydrology. First, there have been few systematic inventories of rock glaciers in mountain regions, despite the pressing need to assess the potential of rock glaciers to contribute to water supply. Second, while much is known of the recession of ice glaciers in response to climate change, much less is known of the rock glacier response. Third, there is as yet incomplete understanding of the amount of ice contained within rock glaciers, especially at the regional scale, and this hampers assessments of the importance of these landforms to providing water supply. As a result, this research proposal will address the first two of these problems and aims to provide a data base from which we can begin to answer the third. We will use remotely-sensed data to map the location, areal extent, and form of rock glaciers in the dry Andes of Bolivia over the last 50 years using fine spatial resolution (5 m) optical satellite data and freely available decommissioned CORONA data from the 1960s. We will use these results to assess rock glacier responses to observed climate change over this period which encompasses the time when attribution studies indicate global temperatures responded to greenhouse gas forcing (IPCC 2007).

该项目旨在调查玻利维亚干旱山区的岩石冰川，并评估其未来对该地区供水的贡献。山地水文在世界许多干旱地区维持社会经济发展中发挥着至关重要的作用。然而，气候变化正在导致山区冰川消退。自 20 世纪 50 年代以来，玻利维亚山区的冰川经历了大幅融化，预计 21 世纪持续变暖将导致冰川进一步衰退并最终消失，特别是在冰川较小的地区。这次冰川衰退威胁到拉巴斯和埃尔阿尔托市未来的供水，对经济发展产生不利影响，并助长社会、政治和生态不稳定。然而，在玻利维亚的几个高干旱山区，大量的冰被岩石冰川包围，这是一种细长的谷底地貌，由岩石碎片和冰的不同混合物组成。这些地貌是许多山地系统水文系统的重要组成部分，将大量的粗细沉积物输送到谷底，形成广泛的潜在水库。由于表面覆盖着岩石碎片，冰含量不受低幅度和高频温度变化的影响，因此，预计岩石冰川对气候变暖的反应比冰冰川更慢。因此，在全球变暖的条件下，它们有可能在未来的水文系统中发挥重要作用，在冰川持续衰退时为山区社区提供供水。尽管如此，仍有一些障碍阻碍了我们更好地了解岩石冰川在调节山区水文方面可能发挥的作用。首先，尽管迫切需要评估岩石冰川促进供水的潜力，但对山区岩石冰川的系统清查却很少。其次，虽然人们对气候变化导致的冰川退缩了解甚多，但对岩石冰川的反应却知之甚少。第三，对岩石冰川中所含冰量的了解尚不完全，尤其是在区域范围内，这阻碍了对这些地貌对供水的重要性的评估。因此，本研究提案将解决前两个问题，并旨在提供一个数据库，让我们可以开始回答第三个问题。我们将使用精细空间分辨率 (5 m) 光学卫星数据和 20 世纪 60 年代免费提供的退役 CORONA 数据，利用遥感数据绘制过去 50 年玻利维亚干燥安第斯山脉岩石冰川的位置、面积范围和形态。我们将利用这些结果来评估岩石冰川对这一时期观测到的气候变化的反应，该时期包括归因研究表明全球温度对温室气体强迫做出反应的时期（IPCC 2007）。