1973~2013年青海湖水面面积变化遥感动态分析

Remote Sensing Monitoring Study for the Tendency of Qinghai Lake’s Water Area in Last 41 Years

摘要: 近年来受到全球气候变化和多种极端天气影响，青海湖水域面积呈现较大波动。为充分掌握青海湖水域面积变化规律，以指导流域水资源配置和生态环境保护，本文分析了青海湖自1973年以来41年的遥感影像，计算出了各年的水面面积，并与多种气象要素对比分析。结果表明，青海湖水域面积在1973~2004年整体减小，并以2004年为分界点，2004~2013年又逐渐增加；2004年相比1973年面积减少了231.4 km2，2013年相比2004年面积增加了134.233 km2。青海湖水面面积受气温和日照影响显著，具有较好相关性；降雨和蒸发与青海湖面积呈现弱相关性。通过综合分析，作者认为青海湖水面面积自2004年快速增加的主要原因有：1) 气温、日照、风速减小，湖区水量损失减小；2) 年降雨量随临近地区冰川融化加快而增加；3) 人类活动影响减小，植被覆盖度增加。

Abstract: In recent years, affected by global climate change and extreme weather events, the water surface area of Qinghai Lake fluctuates significantly. In order to grasp the variability of Qinghai Lake’s water area so as to provide guidance of basin water resource allocation and eco-environmental protection, remote-sensing images from 1973 to 2013 were used to calculate the water area of Qinghai Lake. Results show that Qinghai Lake’s water area has a tendency to decrease from 1973 to 2004 as a whole; and 2004 was found as a turning point, after which it gradually increases up to the end of the study period. Compared with 1973, the water area reduced 231.4 km2 in 2004 and the difference between 2004 and 2013 is 134.233 km2. Analysis of the meteorological data of the same time period indicates that Qinghai Lake’s water area is affected by the air temperature and sunlight significantly, and it has a weak correlation with rainfall and evaporation. The comprehensive analysis reveals that the rapid increase of the water area of Qinghai Lake since 2004 is mainly due to: 1) the decrease in water loss because of the decrease of temperature, sunlight and wind speed; 2) the increase in rainfall resulting from the acceleration of neighborhood glacier melting; and 3) the increase in vegetation coverage because of the limiting human activities policy.