采用地学信息图谱方法,分析了羌塘高原1970—2000年的冰川变化.结果表明:1970—2000年期间,羌塘高原整体呈萎缩趋势,冰川面积退缩的年平均速率(APAC)为0.145%.a-1,年平均退缩面积3.004 km2.a-1,但也有部分冰川处于前进状态.1970—2000年羌塘高原冰川退缩加剧,但与中国西部大部分地区相比,仍是退缩速率较小的地区;整体冰川变化趋势由北向南逐渐增大,但是不同时段不同山地的冰川变化又有所差异.通过分析冰川变化对气候变化的响应可知,气温上升是1970—2000年羌塘高原冰川处于退缩状态的主要原因.对比分析羌塘高原冰川变化实际结果和冰川系统模型的预测结果可知,直线式升温模式下升温速率为0.03 K.a-1时的情形更符合羌塘高原的冰川变化实际情况,也说明冰川系统模型具有可行性.
Global warming has a great impact on glacier variations and is the focus of the various studies.The glaciers are more sensitive in the Tibetan Plateau than in Polar Regions.Thus,it is of significance to research glaciers in the Qangtang Plateau,the hinterland of the Tibetan Plateau.In this paper,Tupu analysis is performed for glacierized area variation during 1970_2000 in the Qangtang Plateau using air photos,photogrammetric maps and satellite images based on the theories and methods of Geo-information Tupu.The result clearly reveals that a few glaciers were actually advancing during 1970_2000 in the Qangtang Plateau.However,the glaciers tended to decrease by a rate of 0.145%/a from 1970 to 2000 with an annual recession area of 3.004 km2 as a whole.Glacier ablation accelerated during 1970—2000,but the retreat rate seemed much less in the study area than that in the most areas of western China.This is because the glaciers in the study area belonged to the extremely-continental type,which responded to climate change slowly.The whole glacier variation in the Qangtang Plateau increased from nouth to south.However,there existed differences in different mountains during different periods.Air temperature rose distinctly,especially the average temperature in warm season,and precipitation mainly increased during 1970_2000 in the Qangtang Plateau.However,the glacier accumulation due to the increasing precipitation was not sufficient to offset glacier ablation due to air temperature warming.Therefore,it is considered that glacier retreat was likely due to air temperature warming during 1970_2000 in the Qangtang Plateau.The functional model of glacier system is used to predict the glacier variation.The results show that the linear warming with temperature rising rate of 0.03 K5a+-1 is much more logical with the real situation of glacier variation than other scenarios after contrasting the predicted results with investigation results.This also demonstrates that the functional model of glacier system is feasible.