SGER: Glacier sensitivity to climate change: Quantifying the influence of tributary glaciers

瑞士的Gornergletscher冰川是阿尔卑斯山的第二大冰川系统，自世纪之交以来，它一直在迅速退缩。初步的数值质量平衡模拟表明，为主要山谷冰川提供补给的支流冰川的变化可能是预测系统对气候变化响应的关键。从模式中排除这些较小的支流冰川低估了冰川末端对气候变化的规模和响应时间。然而，这个模型还不包括冰的动力学。支流冰川内冰的物理和化学性质可能与邻近的支流和主要山谷冰川有很大的不同。因此，支流冰川的物理性质将影响整个冰川系统的动态，影响冰川对气候变化的响应速度和幅度。该项目将研究支流冰川对Gornergletscher系统冰动力的影响，以及支流冰川的变化如何影响高山冰川对气候变化的响应时间和敏感性。这将通过分析几个浅（~15米）冰芯中的冰的化学和物理性质来完成，这些冰芯沿着支流和主要山谷冰川的导线。与沿同一样带的探地雷达（GPR）一起，冰芯数据将确定Gornergletscher支流冰川内冰的物理和化学性质，并量化支流冰川对主要山谷冰川内部冰动力学的影响。在过去的一个世纪里，全球范围内冰川消融的潜在社会影响一直是科学界、经济界和政界讨论的焦点。这些冰川的变化将极大地影响淡水资源、水力发电、旅游业、当地气候和海平面上升等。此外，基于过去冰川范围记录的过去气候重建通常是一个地区气候历史的主要描述，并且已被证明对量化自然气候变率至关重要。数值冰川模式是研究冰川对过去、现在和未来气候变化敏感性的重要工具。然而，上个世纪的冰川退缩比冰川模式预测的要大，这挑战了我们对冰川对气候变化敏感性的理解。鉴于目前世界上许多地区冰川的变薄和退缩速度，提供冰川对气候情景响应的准确重建和预测是当务之急。该项目将大大增加对冰川对气候变化敏感性的认识，提高冰川数值模式的精度。

The Gornergletscher in Switzerland is the second largest glacier system in the Alps, and it has been retreating rapidly since the turn of the century. The rate of this retreat has varied greatly, Preliminary numerical mass-balance modeling indicate that changes in tributary glaciers that feed the main valley glacier may be the key to predicting the response of system to changes in climate. Excluding these smaller, tributary glaciers from models underestimates the magnitude and response time of the glacier terminus to changes in climate. However, the model does not yet include ice dynamics. The physical and chemical properties of ice within tributary glaciers may be drastically different than those of neighboring tributaries and the main valley glacier. It thus follows that physical properties of tributary glaciers will influence the dynamics of the glacier system as a whole, influencing both the rate and magnitude of glacier responses to changes in climate. This project will investigate the influence of tributary glaciers on ice dynamics of the Gornergletscher system, and how changes in tributary glaciers then influence the response time and sensitivity of alpine glaciers to changes in climate. This will be accomplished by analyzing the chemical and physical properties of ice in several shallow (~15 m) ice cores along a traverse through the tributary and main valley glaciers. Together with ground-penetrating radar (GPR along the same transect, the ice-core data will determine the physical and chemical ice properties within tributary glaciers on the Gornergletscher, and to quantify the influence of tributary glaciers on the internal ice dynamics of the main valley glacier.The potential societal impacts of the near world-wide retreat of glaciers over the past century has been of the focus of much discussion in the scientific, economic, and political communities. Changes in these glaciers will greatly affect freshwater resources, hydroelectric power, tourism, local climate, and sea-level rise, among other things. Additionally, past climate reconstructions from records of past glacier extent often serve as the primary descriptor of the climate history of a region, and have proven critical for quantifying natural climate variability. Numerical glacier models are essential tools in studies of glacier sensitivity to climate change past, present, and future However, glacier retreat over the last century has been larger than was predicted by glacier models, challenging our understanding of glacier sensitivity to changes in climate. Given the current thinning and retreat rate of glaciers in many regions of the world, it is imperative that accurate reconstructions and predictions of glacier response to climate scenarios be provided. This project will greatly increase the knowledge of glacier sensitivity to climate change and improve the accuracy of numerical glacier models.