1973-2018年布喀达坂峰地区前进冰川遥感监测

Remote sensing monitoring of advancing glaciers in the Bukatage Mountains from 1973 to 2018

冰川跃动是冰川动力不稳定性的表现,影响着全球约1%的冰川。基于1973-2018年208景Landsat MSS/TM/ETM+/OLI遥感影像,对布喀达坂峰地区不同时期前进冰川进行遥感识别。结果表明:(1)1973-2018年布喀达坂峰地区共有7条冰川发生过前进,其中冰川末端快速退缩型冰川有3条,冰川末端波动前进型和冰川末端稳定型冰川各有2条。莫诺马哈冰川和5Y542H0020冰川可能为跃动冰川,且前者正处于跃动阶。(2)近45年间布喀达坂峰地区7条冰川共出现过25次前进现象,各条冰川发生前进次数均多于(含)2次;前进冰川发生时间主要集中于2000s(7次)和1970s(6次)。该地区冰川在各月份均发生过前进现象,推断该地区前进冰川属斯瓦尔巴型。布喀达坂峰地区冰川前进无明显规律,大多数冰川两次前进时间间隔为10年左右。(3)布喀达坂峰地区冰川前进可能受热控和水控机理共同作用,单一的气候变化尚难以解释其变化机理。

Glacier surging is a performance of glacial dynamic instabilities, which affects about 1 % of glaciers worldwide. Glacier surge refers to the periodically rapid movement of glacier in a short period of time (2-3 a). Compared with the monitoring of ice crevasse change in glacier ablation area and the elevation change of glacier surface, the advance of glacier terminal is the most obvious feature to identify the surging glacier from remote sensing image. Based on 2 08 Landsat MSS/TM/ETM+/OLI remote sensing images from 1973 to 2018, advancing glaciers at different periods in the Bukatage Mountains are recognized. Meanwhile, we have explored the factors affecting the advance of glacier with the combination of meteorological data and established the variational mode of surge glacier terminal on the basis of the existing research for surging glaciers to lay a foundation for the study of the mechanism of glacier surging in this region and provide the basis for the Chinese Advancing Glacier Dataset. The results showed that:(1) There were 7 advancing glaciers in the Bukatage Mountains range from 1973 to 2018, among which 3 glaciers were in the state of fluctuating retreat and 2 glaciers in the state of advancing and fluctuating stability. We inferred that Monuomaha Glacier and the 5Y5 4 2H0 0 2 0 Glacier belonged to surging glaciers, whose fronts were in an active phase.(2) There were 25 advance events for these 7 advancing glaciers in the past 45 years. The frequency of each glacier advance was more than or equal to 2 times and the time of advance was focused on the 2 0 0 0 s (7 times) and the 19 7 0 s (6 times). Additionally, glacier advance occurred in each month, so these advancing glaciers probably belonged to Svalbard glacier. There was no obvious pattern of the glacier advance in the Bukatage Mountains. The time interval between two advances of most glaciers was 10 years.(3) The terminals of advancing glaciers in the Kunlun Mountains exerted different changing patterns because of the geographical location, glacier velocity, glacier morphology and etc. The glacial stage lasted 5 years and was longer compared with other areas of China. These 7 advancing glaciers are shown as the modes of terminal change of the "repeated type" in the Bukatage Mountains range. It was hard to solely explain the trigger mechanism that is so complex in the Kunlun Mountains.