Sensitivity of European glaciers to precipitation and temperature – two case studies
Sensitivity of European glaciers to precipitation and temperature – two case studies
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DOI：
10.1007/s10584-008-9393-1
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发表时间：
2008-03
期刊：
影响因子：
4.8
通讯作者：
D. Steiner;A. Pauling;S. U. Nussbaumer;A. Nesje;J. Luterbacher;H. Wanner;Heinz J. Zumbühl
中科院分区：
文献类型：
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作者：
D. Steiner;A. Pauling;S. U. Nussbaumer;A. Nesje;J. Luterbacher;H. Wanner;Heinz J. Zumbühl
用瑞士阿尔卑斯山下格林德瓦尔德冰川温度和降水的高分辨率多代理重建(输入数据)和冰川长度变化(输出数据)训练了一个非线性反向传播网络(BPN)。然后用从概率方法得出的温度和降水的两种区域气候情景来强迫模型：第一种情景(“无变化”)假定2000-2050年期间的温度和降水与1970-2000年的平均值相比没有变化。在第二种情况(“联合强迫”)中，2000年至2050年期间采用了每年0.036-0.054摄氏度的线性升温速率，降雨率与1970年至2000年的平均值相比变化幅度在−17%至+8%之间。在第一种情况下，下格林德沃冰川显示出持续的后退，直到本世纪20年代达到平衡，然后略有上升。对于第二种情况，模拟的是自1990年代以来每年大约3000万−的强劲和持续的撤退。通过对所使用的气候参数进行基于神经网络的敏感性分析，我们调查了下格林德沃冰川在四个有充分记录的历史进退期(1590-1610、1690-1720、1760-1780、1810-1820)和退缩时期(1640-1665、1780-1810、1860-1880、1945-1970)不同气候配置的相对重要性。结果表明，季节温度和降水的不同组合导致了冰川的变化。以类似的方式，我们确定了降水和温度对众所周知的18世纪早期尼日利亚冰川的进退和20世纪挪威西部冰川退缩的意义。我们发现，海洋尼日利亚冰川比下格林德沃冰川更受冬季和/或春季降水的影响。
A nonlinear backpropagation network (BPN) has been trained with high-resolution multiproxy reconstructions of temperature and precipitation (input data) and glacier length variations of the Alpine Lower Grindelwald Glacier, Switzerland (output data). The model was then forced with two regional climate scenarios of temperature and precipitation derived from a probabilistic approach: The first scenario (“no change”) assumes no changes in temperature and precipitation for the 2000–2050 period compared to the 1970–2000 mean. In the second scenario (“combined forcing”) linear warming rates of 0.036–0.054°C per year and changing precipitation rates between −17% and +8% compared to the 1970–2000 mean have been used for the 2000–2050 period. In the first case the Lower Grindelwald Glacier shows a continuous retreat until the 2020s when it reaches an equilibrium followed by a minor advance. For the second scenario a strong and continuous retreat of approximately −30 m/year since the 1990s has been modelled. By processing the used climate parameters with a sensitivity analysis based on neural networks we investigate the relative importance of different climate configurations for the Lower Grindelwald Glacier during four well-documented historical advance (1590–1610, 1690–1720, 1760–1780, 1810–1820) and retreat periods (1640–1665, 1780–1810, 1860–1880, 1945–1970). It is shown that different combinations of seasonal temperature and precipitation have led to glacier variations. In a similar manner, we establish the significance of precipitation and temperature for the well-known early eighteenth century advance and the twentieth century retreat of Nigardsbreen, a glacier in western Norway. We show that the maritime Nigardsbreen Glacier is more influenced by winter and/or spring precipitation than the Lower Grindelwald Glacier.