This study extends knowledge of the evolution of glacier shrinkage in the Cocuy-Güican Mountains since the maximum glacier extent of the Little Ice Age (LIA). Mass balance data for the Ritacuba Glacier since 2009 were acquired and compared with available data for the Conejeras Glacier (Los Nevados National Park). This study also investigated the hydrological significance of Colombian glaciers, which is still largely unknown because the available information is very limited. Glaciers in the Cocuy-Güican Mountains covered 13.2 km² in 2019 compared with 127.8 km² during the maximum LIA, representing a shrinkage of 89.7%. Analysis of glacier cover observations made in 1955, 1994, 2010, and 2019 revealed that the rate of ice loss was greatest from 1994 to 2010 (0.59 km² yr⁻¹), and was then almost halved from 2010 to 2019 (0.34 km² yr⁻¹). This slowing of glacier retreat is consistent with the moderate negative mass balance measured for 2009–2019, and an accumulated loss of 1766 mm w.e. (mm water equivalent). The progressive confinement of glaciers to higher elevations, ice accumulation in topographic locations providing shelter from solar radiation, and an absence of recent marked climatic anomalies could explain why the Cocuy-Güican glaciers have temporally reached a near equilibrium state conditions. This contrasts with the Conejeras Glacier, where 47,000 mm w.e. has been lost in the same period. The available data on runoff and isotope tracers of streamflow and precipitation suggest that precipitation rather than glacier melt water exerts primary control over the hydrological variability at high elevation sites.

中文翻译：

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Cocuy-Güican 山脉（哥伦比亚安第斯山脉）冰川的近期演变及其水文影响

这项研究扩展了自小冰河时代 (LIA) 的最大冰川范围以来 Cocuy-Güican 山脉冰川收缩演变的知识。获取了自 2009 年以来 Ritacuba Glacier 的质量平衡数据，并与 Conejeras Glacier（Los Nevados 国家公园）的可用数据进行了比较。这项研究还调查了哥伦比亚冰川的水文意义，由于可用信息非常有限，这在很大程度上仍然是未知的。Cocuy-Güican 山脉的冰川在 2019 年覆盖了 13.2 km ²，而 LIA 最大时为 127.8 km ²，收缩了 89.7%。对 1955 年、1994 年、2010 年和 2019 年冰川覆盖观测的分析表明，1994 年至 2010 年的冰川流失率最大（0.59 km ² yr ^-1），然后从 2010 年到 2019 年几乎减半（0.34 km ²  yr ^-1）。冰川退缩的这种放缓与 2009-2019 年测量的适度负质量平衡一致，累积损失 1766 毫米我们（毫米水当量）。冰川逐渐被限制在更高的海拔，冰在地形上的积聚为太阳辐射提供庇护，以及近期没有明显的气候异常，这可以解释为什么 Cocuy-Güican 冰川暂时达到了接近平衡状态的条件。这与 Conejeras Glacier 形成鲜明对比，我们在同一时期损失了 47,000 毫米。关于径流和径流和降水同位素示踪剂的可用数据表明，降水而不是冰川融水对高海拔地区的水文变化具有主要控制作用。