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首页> 外文期刊>Journal of Glaciology >Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia
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Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia

机译：俄罗斯/乔治亚州高加索山脉20世纪晚期冰川变化

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Glaciers occupy an area of ~1600kma in the Caucasus Mountains. There is widespread evidence of retreat since the Little Ice Age, but an up-to-date regional assessment of glacier change is lacking. In this paper, satellite imagery (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus) is used to obtain the terminus position of 113 glaciers in the central Caucasus in 1985 and 2000, using a manual delineation process based on a false-colour composite (bands 5, 4, 3). Measurements reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% advanced. The mean retreat rate equates to ~8 m a"1, and maximum retreat rates approach ~38 m a"1. The largest (>10 km2) glaciers retreated twice as much (~l2ma-1) as the smallest (<1 km2) glaciers (~6ma-1), and glaciers at lower elevations generally retreated greater distances. Supraglacial debris cover has increased in association with glacier retreat, and the surface area of bare ice has reduced by ~10% between 1985 and 2000. Results are compared to declassified Corona imagery from the 1960s and 1970s and detailed field measurements and mass-balance data for Djankuat glacier, central Caucasus. It is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid-1990s. Continued retreat could lead to considerable changes in glacier runoff, with implications for regional water resources.
机译：高加索山脉的冰川面积约1600kma。自小冰河时代以来，有广泛的退缩证据，但缺乏对冰川变化的最新区域评估。在本文中，通过基于假彩色复合物的人工描绘过程（波段5），利用卫星图像（Landsat Thematic Mapper和Enhanced Thematic Mapper Plus）获得了1985年和2000年高加索中部113个冰川的终点位置。 ，4、3）。测量结果显示，有94％的冰川已经退缩，其中4％的冰川没有整体变化，而2％的冰川已经退缩。平均撤退速率等于〜8 m a-1，最大撤退速率接近〜38 m a-1。最大的（> 10 km2）冰川后退（〜1ma-1）是最小（<1 km2）冰川（〜6ma-1）的两倍，而海拔较低的冰川通常后退距离更大。冰川上的退缩增加了冰川上的碎片覆盖，1985年至2000年期间裸冰的表面积减少了约10％。将结果与1960年代和1970年代解密的Corona影像以及详细的现场测量和质量平衡数据进行了比较高加索中部Djankuat冰川。结论是，自1970年代以来，尤其是1990年代中期以来，冰川面积的减少似乎主要是由温度升高引起的。持续的退缩可能会导致冰川径流发生重大变化，从而对区域水资源产生影响。

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