Variability of the climatic mass balance of Vestfonna ice cap, northeastern Svalbard, 1979-2011
Variability of the climatic mass balance of Vestfonna ice cap, northeastern Svalbard, 1979-2011
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DOI：
10.3189/2013aog63a407
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发表时间：
2013-01-01
影响因子：
2.9
通讯作者：
Schneider, Christoph
中科院分区：
文献类型：
--
作者：
Moeler, Marco;Finkelnburg, Roman;Schneider, Christoph
位于斯瓦尔巴群岛东北部的维斯福纳冰盖是欧洲北极地区最大的冰体之一，但人们对其物质平衡的演变知之甚少。本研究重建了1979/80-2010/11年间冰盖的气候物质平衡。重建基于质量平衡模型的计算，该模型结合了地表高度相关的积累方案和空间分布的温度指数消融模型（包括净短波辐射）。包括重新冻结，基于基本的P-max方法。该模式考虑了云覆盖效应和地表反照率的变化，这些变化由统计反照率模式计算得到。使用ERA-Interim导出的气温、降水和总云量数据作为输入。结果表明，研究期间的平均气候质量平衡率为+0.09 +/- 0.15 m w.e.a（-1）。在研究期间，年度结余显示出轻微的、不显著的趋向于负值的趋势。据估计，再冻结对年累积量的贡献约为三分之一，在研究期间，再冻结呈显著的正趋势。模拟结果显示，近年来气候质量平衡梯度明显变陡，典型的3个月消融期延长。
Vestfonna ice cap, northeastern Svalbard, is one of the largest ice bodies in the European Arctic, but little is known about the evolution of its mass balance. This study presents a reconstruction of the climatic mass balance of the ice cap for the period 1979/80-2010/11. The reconstruction is based on calculations using a mass-balance model that combines a surface-elevation-dependent accumulation scheme with a spatially distributed temperature-index ablation model that includes net shortwave radiation. Refreezing is included, based on the basic P-max approach. The model accounts for cloud-cover effects and surface albedo variations that are calculated by a statistical albedo model. ERA-Interim derived air temperature, precipitation and total cloud-cover data are used as input. Results reveal a mean climatic mass-balance rate of +0.09 +/- 0.15 m w.e. a(-1) for the study period. Annual balances show a slight, insignificant trend towards less positive values over the study period. Refreezing is estimated to contribute about one-third to annual accumulation, and a significant positive trend in refreezing is present over the study period. The modelling results reveal a significant steepening of the climatic mass-balance gradient and indicate a lengthening of the characteristic 3 month ablation period in recent years.