Abstract An Empirical Orthogonal Function (EOF) variance analysis was performed to map in detail the spatiotemporal variability in individual stake mass-balances (ba) on Mittivakkat Gletscher (MG) – in a region where at present five out of ~20.000 glaciers have mass-balance observations. The EOF analysis suggested that observed ba was summarized by two modes: EOF1 and EOF2 represented 80% (significant) and 6% (insignificant) of the explained variance, respectively. EOF1 captured a decline in ba that was uniformly distributed in space at all stakes. The decline was correlated with albedo observations and air temperature observations from nearby stations. EOF2, however, described variations in ba that were heterogeneously distributed among stakes and associated with local slope and aspect. Low elevation stakes (~<400 m a.s.l.) showed relatively negative (out of phase) correlation and higher elevated stakes relatively positive (in phase) eigenvector correlation values with EOF2. Such relatively negative and positive eigenvector correlation values were present where the constituted of exposed glacier ice or snow cover, respectively. The results from this study show how EOF analyses can provide information on spatiotemporal patterns of glacier mass-balance. Understanding such detailed variabilities in mass-balance on a Greenlandic glacier is of interest because a fifth of the Arctic contribution from glaciers and ice caps to sea-level rise originates from Greenland.

中文翻译：

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时空冰川质量平衡变化的统计 EOF 分析：格陵兰东南部 Mittivakkat Gletscher 的案例研究

摘要 进行了经验正交函数 (EOF) 方差分析，以详细绘制 Mittivakkat Gletscher (MG) 上单个桩质量平衡 (ba) 的时空变异性 - 在该地区，目前约 20.000 条冰川中有五个具有质量-平衡观察。EOF 分析表明观察到的 ba 由两种模式总结：EOF1 和 EOF2 分别代表解释方差的 80%（显着）和 6%（不显着）。EOF1 捕获了 ba 的下降，该下降在所有赌注的空间中均匀分布。这种下降与附近站点的反照率观测和气温观测有关。然而，EOF2 描述了 ba 的变化，这些变化在桩之间异质分布并与当地的坡度和坡向相关。低海拔桩 (~<400 m asl ) 显示出相对负 (异相) 相关性和更高的风险与 EOF2 相对正 (同相) 特征向量相关值。这种相对负和正的特征向量相关值分别存在于由暴露的冰川冰或雪覆盖构成的地方。这项研究的结果显示了 EOF 分析如何提供有关冰川质量平衡的时空模式的信息。了解格陵兰冰川质量平衡的如此详细的变化很有趣，因为冰川和冰盖对海平面上升的北极贡献的五分之一来自格陵兰。这种相对负和正的特征向量相关值分别存在于由暴露的冰川冰或雪覆盖构成的地方。这项研究的结果显示了 EOF 分析如何提供有关冰川质量平衡的时空模式的信息。了解格陵兰冰川质量平衡的如此详细的变化很有趣，因为冰川和冰盖对海平面上升的北极贡献的五分之一来自格陵兰。这种相对负和正的特征向量相关值分别存在于由暴露的冰川冰或雪覆盖构成的地方。这项研究的结果显示了 EOF 分析如何提供有关冰川质量平衡的时空模式的信息。了解格陵兰冰川质量平衡的如此详细的变化很有趣，因为冰川和冰盖对海平面上升的北极贡献的五分之一来自格陵兰。