Dynamic Response of Glaciers in the Qilian Shan to Climate Change (Dyn-Q)

关于冰川和融水变化的知识对于中亚的可持续供水至关重要，因为它们是数百万人的水塔。祁连山位于青藏高原的最东北部，在中国青海和甘肃的边界上，为周边地区，特别是河西走廊提供了重要的水资源，是中国西北最重要的农业区。近几十年来，随着气温的升高和河西走廊沙漠化的加剧，祁连山地区特别是中东部地区的冰川迅速大量流失。这些山区的冰川是自然环境的重要组成部分，形成了对生态系统和当地人口都至关重要的水资源。祁连山冰川多为夏季累积型冰川，易受当前全球变暖趋势的影响，由于反馈机制的作用，冰川正在快速萎缩。“祁连山冰川对气候变化的动态响应”（Dyn-Q）项目的主要目标是通过模拟大气强迫下祁连山冰川流动模式和几何形状的时间综合变化，包括气候变化引起的能量和物质平衡分量的变化及其对区域水资源的影响，提高对祁连山大气-冰冻圈耦合的认识。能量平衡的主要反馈机制是，融冰季节气温的升高触发冰川冰温升高，导致流动模式的改变和冰川表面反照率的降低，特别是在夏季，由于降水由固体到液体的相变。在Dyn-Q中，我们建议将流动动力学、表面能和质量平衡模型直接耦合几十年，以提供包含所有相关物理过程的更精确的响应模式。这种方法需要将三维冰流模型与物理能量和质量平衡模型相结合。我们假设，冰川对变化的气候强迫响应的耦合模拟比仅使用与冰流模型相结合的度日方法或忽略冰动力学的物理气候表面能量质量平衡模拟所预期的要明显得多。在Dyn-Q项目中，我们将利用考虑冰动力和表面能量和质量平衡的两个耦合模型，重建祁连山两个基准冰川在遥感期间（1980-2010）的演变。目的是评估当前这些冰川对气候变化的敏感性，并利用在Dyn-Q中建立的耦合模型链，预测未来几十年冰川几何形状的演变及其对当地水资源的贡献。

Knowledge on glacier and melt water variability is crucial for sustainable water supply in Central Asia since they function as water towers for millions of people. The Qilian Shan, are located in the most Northeastern part of the Tibetan Plateau, on the border between Qinghai and Gansu Province in China provide important water resources to nourish peripheral areas, especially the Hexi Corridor, which is the most important agricultural area in Northwest China. In recent decades, along with increasing air temperature and the desertification of Hexi Corridor, glaciers in Qilian Mountain, especially in the middle and east part, experience rapid mass wastage. Glaciers in these mountain areas are important elements of the natural environment forming water resources of cardinal importance both for ecosystems and local population. Glaciers in Qilian Shan are mostly summer-accumulation-type glaciers, being reported to be vulnerable to the current global warming trend and are experiencing rapid shrinkage due to feedback mechanisms. The main objective of the proposal Dynamic Response of Glaciers in the Qilian Shan to Climate Change (Dyn-Q) is to improve the understanding of atmosphere-cryosphere coupling in the Qilian Shan by modelling the temporally integrated variations in glacier flow patterns and geometry due to atmospheric forcing, including variations in energy and mass balance components induced by climate change and their impact on regional water resources. Main feedback mechanisms within energy balance are that the increase in air temperature during the melting season triggers both the increase in glacier ice temperatures resulting in changed flow patterns and the reduction of albedo at the glacier surface, especially during the summer season due to a phase change of precipitation from solid to liquid. Within Dyn-Q we propose the direct coupling of flow dynamics and surface energy and mass balance modelling over periods of decades to provide much more precise response patterns that comprise all relevant physical processes. This approach necessitates coupling a three dimensional ice flow model with a physical energy and mass balance model. We hypothesize that coupled modelling of the glacier response to varying climate forcing can be much more pronounced than would be anticipated from either using only degree-day approaches combined with an ice flow model or physical climatic surface energy mass balance modelling but neglecting ice dynamics. Within Dyn-Q we will reconstruct the evolution of two benchmark glaciers in the Qilian Shan over the period of remote sensing (1980-2010) using two coupled models that account for ice dynamics and surface energy and mass balance. The aim is to evaluate the current sensitivity of these glaciers to climate change and to project the evolution of their geometry and contribution to local water resources in coming decades using the coupled model chain to be established within Dyn-Q.