ABSTRACT The evolution of Mexican glaciers (19° N) in the climate context is poorly understood despite these glaciers are important indicators of regional climate change. The detailed patterns of glacier recession since the Little Ice Age (LIA) have exacerbated during the past years and decades. Their relationship to local and regional climate change needs further analysis. This study compares the changes of the largest glacier in Mexico, Glaciar Norte (GN), on Citlaltépetl Volcano with temperature, precipitation, and surface energy balance variations that were considered as part of climate forcing. Area, length, elevation, equilibrium line altitude (ELA), and thickness were calculated from historical and satellite data sets and a high-resolution Digital Elevation Model. The results showed that during the 1990s, prevailing warm and variable dry conditions enhanced the glacier retreat, triggering the disappearance of Jamapa glacier tongue. The glacier length has changed at the rate of −20.7 m a−1 since 1958. ELA varied from 4999 m a.s.l. in 1958–5228 m a.s.l. in 2017. A short period of snow accumulation from 2007 to 2009 was found when the annual temperature over GN showed a noticeable negative trend similar to that for the accumulated surface energy balance. The surface energy balance was conclusive on the response of GN to stability or accumulation periods. Finally, the long-term variation of temperature was the only factor found forcing the glacier retreat. Assuming that the retreat rate (−0.02 km a−1) and climate tendencies remained constant (0.1°C/decade), GN could disappear towards the middle of the twenty-first century.

中文翻译：

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自 50 年代以来墨西哥最大冰川（北冰川）的演变：推动冰川退缩的因素

摘要 尽管这些冰川是区域气候变化的重要指标，但人们对气候背景下的墨西哥冰川（19° N）的演变知之甚少。自小冰河时代 (LIA) 以来，冰川衰退的详细模式在过去几年和几十年中加剧了。它们与地方和区域气候变化的关系需要进一步分析。本研究比较了墨西哥最大的冰川北冰河 (GN) 在 Citlaltépetl 火山上的变化与温度、降水和地表能量平衡变化，这些变化被认为是气候强迫的一部分。面积、长度、海拔、平衡线高度 (ELA) 和厚度是根据历史和卫星数据集以及高分辨率数字高程模型计算的。结果表明，在 1990 年代，盛行的温暖和多变的干燥条件增强了冰川退缩，引发了贾马帕冰川舌的消失。自 1958 年以来，冰川长度以 -20.7 m a-1 的速率变化。ELA 从 1958 年的 4999 m asl 变化到 2017 年的 5228 m asl。当年温度超过 GN 时，发现了 2007 年至 2009 年的短暂积雪显示出与累积表面能平衡相似的明显负趋势。表面能量平衡对 GN 对稳定期或积累期的响应是决定性的。最后，温度的长期变化是发现迫使冰川退缩的唯一因素。假设后退速率（-0.02 km a-1）和气候趋势保持不变（0.1°C/十年），GN 可能会在 21 世纪中叶消失。