Glacier surface temperature is not only an important indicator of climate change, but is also directly related to glacier physical processes and mass balance. Glaciers over the Third Pole have shown heterogeneous but accelerated mass loss over the past two decades. However, few studies have focused on changes of glacier surface temperature in this region. In this study, we investigate this change from 2000 to 2021 using an altitudinal area-weighting method based on Landsat surface temperature products. The results show that this method can robustly derive inter-annual variability and long-term trends of subregional glacier surface temperature. Over the entire Third Pole, glacier surfaces exhibited warming at the rate of +0.17 ± 0.35 °C dec ( = 0.32). The warming had a distinct seasonal pattern: warming in autumn (+0.50 ± 0.53 °C dec, = 0.06) but cooling in spring (−0.22 ± 0.36 °C dec, = 0.23). Correspondingly, the ablation season 0 °C isotherm altitude has risen >100 m and the glacier area with GST ≥0 °C has expanded by 10%. Moreover, the GST changes displayed large spatial heterogeneity. In the westerlies-dominated regions (e.g., Karakoram and Kun Lun), glacier surfaces showed slight warming or even cooling on average (from −0.10 to +0.06 °C dec), while in the monsoon-dominated regions (e.g., East Himalaya, Southeast Tibetan Plateau and Hengduan Mountains), strong warming was observed (> +0.50 °C dec, < 0.05). Glacier surfaces generally showed a faster warming at north slopes than south slopes, especially in the ablation season. These results emphasize that different magnitudes of glacier surface warming are important indicators for the contrasting glacier changes over the Third Pole. The method presented here opens the way to investigate long-term surface temperature change of global mountain glaciers, which can help us further understand the mechanisms of glacier response to global climate change.

中文翻译：

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2000年至2021年第三极冰川表面温度变化

冰川表面温度不仅是气候变化的重要指标，而且与冰川物理过程和质量平衡直接相关。在过去的二十年里，第三极的冰川表现出异质性，但质量损失加速。然而，很少有研究关注该地区冰川表面温度的变化。在本研究中，我们使用基于陆地卫星表面温度产品的海拔面积加权方法研究了 2000 年至 2021 年的这一变化。结果表明，该方法可以稳健地推导次区域冰川表面温度的年际变化和长期趋势。在整个第三极，冰川表面的变暖速度为+0.17 ± 0.35 °C dec (= 0.32)。变暖具有明显的季节性模式：秋季变暖（+0.50 ± 0.53 °C dec，= 0.06），但春季变冷（−0.22 ± 0.36 °C dec，= 0.23）。相应地，消融季0℃等温线海拔上升>100m，GST≥0℃的冰川面积扩大10%。此外，商品及服务税的变化表现出较大的空间异质性。在西风主导的地区（如喀喇昆仑和昆仑），冰川表面平均略有变暖甚至变冷（从-0.10℃到+0.06°C dec），而在季风主导的地区（如东喜马拉雅、青藏高原东南部和横断山脉），观测到强烈变暖（> +0.50 °C dec，< 0.05）。北坡冰川表面的变暖速度通常比南坡更快，特别是在消融季节。这些结果强调，不同程度的冰川表面变暖是第三极对比冰川变化的重要指标。该方法为研究全球山地冰川长期表面温度变化开辟了道路，有助于我们进一步了解冰川对全球气候变化的响应机制。