基于TM 影像和DEM 的白碱湖湖面变化模拟

史前时期, 在石羊河下游存在着一个面积广大的统一终端湖--猪野泽, 随着气候的变化和人类活动的加剧, 猪野泽逐渐分裂、瓦解并最后完全干涸, 遗留下众多的终端湖残迹, 白碱湖为其中规模最大、干涸最晚者。以TM 遥感影像为数据源, 通过影像增强, 突出了白碱湖北岸岸坡上呈水平平行状分布的一组色调相间变化的条带。经过判读、对比分析和在GPS 导航下的实地考察, 其中的8 条被确认为曾经的湖岸线。利用该地区1∶5 万DEM , 读取这些湖岸线现代条件下的高程, 并在GIS 中对各湖岸线相应的湖面面积和水量进行了计算。结果表明, 白碱湖湖面的最高高程约1 320 m , 相应的最大湖面面积为1 600 km ², 其后经历过多次规模不等的退缩, 直至上个世纪完全干涸。

A Study on the Changes of Baijian Lake Based on TM Image and DEM

In the prehistoric time, there was a large uniform terminal lake named Zhuyeze in the lower reaches of Shiyang River. Along with the climate change and human activities, Zhuyeze began become separated and dry gradually. Lots of small lakes vestiges were left behind in this area. Among them , Baijianhu Lake is the largest. This article take TM image as the data source, after image enhancement, a group of alternate-color stripes which exist on the north bank of Baijianhu Lake were high lighted. After interpretation, analyses and investigation, 8 of them were confirmed as the once lakeshore lines. Using 1∶50 000 DEM , the modern altitudes of these linesw ere obtained and the corresponding areas were calculated in GIS environment. The results show that the highest elevation of Baijianhu Lake was once 1 320 m with the area 1 600 km2. After that, Baijianhu Lake began shrink until dried completely in last century.