We examine the spatial patterns of near-surface air temperature (Ta) over a melting glacier using a multi-annual dataset from McCall Glacier, Alaska. The dataset consists of a 10-year (2005–2014) meteorological record along the glacier centreline up to an upper glacier cirque, spanning an elevation difference of 900 m. We test the validity of on-glacier linear lapse rates, and a model that calculates Ta based on the influence of katabatic winds and other heat sources along the glacier flow line. During the coldest hours of each summer (10% of time), average lapse rates across the entire glacier range from −4.7 to −6.7°C km−1, with a strong relationship between Ta and elevation (R2 > 0.7). During warm conditions, Ta shows more complex, non-linear patterns that are better explained by the flow line-dependent model, reducing errors by up to 0.5°C compared with linear lapse rates, although more uncertainty might be associated with these observations due to occasionally poor sensor ventilation. We conclude that Ta spatial distribution can vary significantly from year to year, and from one glacier section to another. Importantly, extrapolations using linear lapse rates from the ablation zone might lead to large underestimations of Ta on the upper glacier areas.

中文翻译：

---

模拟阿拉斯加麦考尔冰川十年融化季节的近地表气温空间模式

我们检查了近地表气温的空间模式（吨一种) 使用来自阿拉斯加麦考尔冰川的多年数据集在融化的冰川上空。该数据集包括一个 10 年（2005-2014 年）的气象记录，沿冰川中心线一直延伸到上冰川冰斗，跨越 900 m 的高差。我们测试了冰川上线性递减率的有效性，以及一个计算模型吨一种基于沿冰川流动线的下风和其他热源的影响。在每年夏季最冷的时段（10% 的时间），整个冰川的平均递减率范围为 -4.7 至 -6.7°C km-1, 之间有很强的关系吨一种和海拔（R2> 0.7)。在温暖的条件下，吨一种显示了更复杂的非线性模式，流线相关模型可以更好地解释这些模式，与线性递减率相比，误差最多可减少 0.5°C，尽管由于偶尔传感器通风不良，这些观察结果可能与更多不确定性相关。我们得出结论吨一种空间分布每年都有很大差异，从一个冰川部分到另一个冰川部分。重要的是，使用消融区的线性失效率进行外推可能会导致严重低估吨一种在上冰川地区。