青藏高原山地湖泊扩涨与山地关系分析

Relationship between the expansion of mountain lakes and their catchment mountains on the Qinghai-Tibet Plateau

基于1∶10万与1∶50万地形图,考察了青藏高原的山地湖泊及其流域的河流(水文)、雪线、冰川高度、各高度山地面积与湖泊面积之间的关系。高原湖泊的规模与流域山地(其高度,中、西部湖拔大于500～750m,东部大于250m)存在密切关系。揭示山地降水是湖泊水的主要来源,其质(低温)与量是维持湖泊一定规模与稳定存在的主要因素。由于山地湖泊存在这种特殊的水文特点,因此,地质历史时期的暖湿期,高原山地湖泊比之低地、丘陵湖泊,扩涨规模可能更为显著。40～23kaB.P,高原山地湖泊异乎寻常地扩涨,可能是降水在暖期季风雨增加时,在山地区增高更甚,更多的低温水流贮湖泊造成的。

Based on the 1：100,000 and 1：500,000 topography maps, the authors investigated rivers （hydrology）, snow fines, glacier lake basins on the heights and relationships of the lake area and mountain area at different heights in mountain Qinghai-Tibet Plateau. The area of plateau lakes is closely related with that of their catchment mountains （the elevations are 〉500-750 m above the present lake level in the central and western parts of the plateau and 〉250 m above the lake level in the eastern part of the plateau）. These suggest that mountain precipitation is probably the main source of lake water and that its quality （low temperature） and quantity are the main factors for maintaining the size and stability of the lakes. Owing to these special hydrological characteristics, the mountain lakes on the plateau expanded more significantly than lowland and hill lakes during the warm-wet period in the geologic past. At 40-23 ka BP, the mountain lakes on the plateau underwent unusual expansion, which was probably because more moisture was transported to the mountainous areas and more low-temperature water flowed to and stored in the mountain lakes during the increase of monsoonal rain in the warm period.