青藏高原上的内陆湖泊群是气候变化的敏感指示器,获取近几十年来湖泊变化的动态信息对研究区域气候及环境变化具有重要的意义.本文讨论了多时相遥感湖泊变化研究中的几个关键问题--湖泊变化季节性因素、湖泊变化信息的提取以及大区域湖泊变化的分析方法,并利用Landsat长时间序列遥感数据,制作青藏高原1970s,1990s,2000s和2009年四个时段的湖泊分布图及其湖泊变化图,分析三十多年来内陆封闭流域内湖泊变化的时空特征,研究结果表明,Landsat MSS/TM/ETM+多时相数据在对0.1km2 以上湖泊进行变化分析时能取得较好的结果.湖泊在一年之内最稳定的时段为9-12月,其最大湖泊面积变化率不超过2%.从湖泊变化的时间过程来看,湖泊总面积在1970s-1990s呈萎缩趋势,在1990s-2009年剧烈扩张,1970s-2009年全时段湖泊总面积增长27.3%.从空间分布来看,湖泊变化具有明显的区域分布特性,藏北羌墉高原区湖泊出现先萎缩后扩张的变化,色林错及周边区域湖泊处于持续扩张的状态.而冈底斯山北麓的高山深谷湖泊则在近三十多年来保持相对稳定的状态.%Numerous inland lakes of the Tibetan Plateau play sensitive indicators to climate change, and mapping and monitoring these lakes would facilitate our understanding of regional climate and environmental changes. The paper is mainly focused on issues of lake mapping and detecting techniques based on multi-temporal remote sensing imagery, and the differences of lake seasonal and decadal changes were also analyzed. With a series of Landsat MSS/TM/ETM + imagery in recent 30 years, Tibetan lakes in 1970s,1990s, 2000s and 2009 are mapped and their changes are detected temporally and spatially. The lake mapping results showed that Landsat datasets have a good performance on lake area mapping whose lake areas are larger than 0. lkm2. There are minor seasonal variations of lake areas from September to December, so that the season could be taken as the best time periods for lake area mapping. The maximum rate of lake area change is less than 2％. Temporally, lakes presented a shrinking trend during 1970s-1990s, while an expanding trend during 1990s -2009, and the total lake area change rate during 1970s -2009 is 27.3％. Spatially, lakes changing rates varied with their spatial locations: lakes in Qiangtang Plateau show dramatic shrinking changes during 1970s - 1990s while expanding changes during 1990s - 2009; lakes in Selin Co Basin and its surrounding areas show expanding changes in the past 30 years, while lakes in northern valley of the Kangdese and southern Kunlun Mountains remain relatively stable.
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