1992—2009年格拉丹东冰川及冰前湖面积变化的遥感研究

Variations of glaciers and glacial lake in Geladandong mountain range in 1992—2009 with remote-sensing technology

针对目前格拉丹东地区冰川遥感观测资料精度和时间连续性有限以及冰前湖资料尚缺的情况,结合高精度分类和人工解译算法,提取格拉丹东地区冰川与冰前湖面积参数并矢量化,然后对当年中多期遥感影像对应的矢量边界进行综合评判,消除阴影、云和季节性积雪的影响,获取格拉丹东冰川和冰前湖近20a来的变化信息。研究结果表明:1992—2009年,冰川面积共减少66.68 km2(减少率为7.37%),其中,在1992—1999年、1999—2006年和2006—2009年这3个时段内分别减少19.90km2(减少率为2.84 km2/a),39.95 km2(5.71 km2/a)和6.83 km2(2.28km2/a),冰川处于连续退缩状态;而冰前湖面积共增加0.1 km2(增大率为52.6%),在上述相应3个时段内分别增加0.04 km2(增大率为0.006 km2/a),0.05 km2(0.007 km2/a)和0.01km2(0.003 km2/a),处于连续扩张状态,两者紧密相连,呈非线性负相关。研究区域内几乎所有冰舌都在退缩,但雪山东侧的冰舌比西侧退缩更严重。夏季气温的显著升高可能是造成冰川持续退缩的主要因素。

Considering the accuracy and continuity of glacier remote sensing observations in Geladandong Mountains are very limited, and the data of glacial lakes are in extreme absence, the detailed variations of glaciers and glacial lakes were studied in 1992—2009. The highly accurate classification and manual interpretation method were used to eliminate the influence of shadow, cloud and seasonal snow. The results show that the glacier area decreases by 66.68 km^2（the decrease rate is 7.37%） in 1992—2009, while the glacial lake area increases by 0.1 km^2（the increase rate is 52.6%）.The glacier areas shrink by 19.90 km^2（2.84 km^2/a）, 39.95 km^2（5.71 km^2/a） and 6.83 km^2（2.28 km^2/a）, in 1992—1999, 1999—2006and 2006—2009,respectively and the glacial lake grows continuously by 0.04 km^2（0.006 km^2/a）, 0.05 km^2（0.007 km^2/a）and 0.01 km^2（0.003 km^2/a） during the same periods, respectively, suggesting that variability of glaciers and glacial lake shows the negative nonlinear relationship. The tongues of glaciers in study area continues to retreat and shrink, and the glaciers on the east of the mountain tends to relatively lose more than those on the western. Glacier area loss mainly results from rising summer temperature.