中文摘要：

基于卫星影像数据，从湖水位、水面面积、湖岸线三个方面分析了1956-2011年青海湖的变化特征，结果表明：56 a间水位累计下降3.28 m；2005年是青海湖由萎缩转为扩张的转折年份，2005-2011年湖水位累计涨幅1.01 m；水面面积与湖水位有很好的正相关关系，1956-2004年萎缩了397.5 km^2，2005-2011年扩张了80.4 km^2；1995年以来沙岛湖一直与大湖水体分离，湖岸线变化不均匀；水位变化的主要影响因素是降水径流的变化，气温、蒸发、冰川融水、人类活动等其他原因并非主导因素。

英文摘要：

This paper analyzed the chanfes of Qinfhai Lake durinf the period of 1956-2011 from three aspects：water level,water surface area and lake shoreline. The results show that the water level dropps about 3. 28m in these 56 years,while raises 1. 01m from durinf the period of 2005 to 2011;lake surface area and lake water level have a food positive correlation accordinf to the landsat imafe data analysis;the lake surface area has reduced 397. 5km^2 from 1956 to 2004 and expanded 80. 4 km^2 from 2005-2011;the Shadao Lake has isolated from the main lake body since 1995,and lake shoreline chanfes unevenly;the main influence factor for water level chanfe is the chanfe of rainfall and runoff,while the other factors includinf temperature,evaporation,flacier melt water and human activities are not dominant factors.