近50年来柴达木盆地湿地变迁及其气候背景分析

Changes of Wetland in Qaidam Basin in the Past 50 Years and Analysis of Climatic Background

在RS/GIS技术的支持下,以1956年航片绘制的1∶10万地形图、1990年前后TM遥感图像及2000年前后ETM遥感图像为主要数据源,结合柴达木盆地8个气象测站温度、降水资料,研究了柴达木盆地湿地的分布特点、近50年来的面积变化和相关气候背景。研究结果表明:柴达木盆地年均温度和降水总体呈上升趋势,而增温更为强烈,年均降水量微弱增加,1990～2000年为明显的暖干时期;柴达木盆地湿地在1956～2000年特别是1990～2000年间总体萎缩趋势严重,盆地边缘区和较大河流附近湿地呈现波动变化,区域气候变化和人类活动应为研究区内湿地变化的主要因素,盆地中西部湿地萎缩主要受到温度升高、人类活动加剧等因素影响,盆地边缘湿地面积少量增加主要受到降水量增加的影响。

Based on the 1 ： 100 000 topographic maps of Qaidam Basin on 1956＇s aerial photographs, remote sensing images of Landsat TM in 1990 and Landsat ETM in 2000,and the temperature and precipitation data of eight weather stations in Qaidam Basin,the distribution patterns of wetland, changes of wetland and background of climate factors were studied by using RS and GIS techniques. During 1956 and 2000,the average annual temperature and average precipitation in Qaidam Basin show an increasing trend, with the former rising significantly, with warm-dry period from 1990 to 2000. The trend of wetland degradation in Qaidam Basin is serious during 1956~2000 especially in 1990s. In the edge area of Qaidam Basin and along large rivers, there was a fluctuation trend of wetland, caused by climatic changes and human activities, i. e. , the degradation of wetland in central and western basin is caused by temperature rise and human activities, while the slight increasing of wetland in edge area of the basin is caused by average annual precipitation change.