新疆车尔臣河绿色走廊河湖湿地变化及原因分析

Change and Causes of the River-lake Marshes along the Green Corridor at the Lower Reaches of the Qarqan River

沙漠中的湖泊湿地是环境变化的敏感区域。利用2000-2010年北京一号小卫星、环境星、中巴资源卫星和Landsat TM数据,车尔臣河绿色走廊河湖湿地进行了连续的动态监测。结果表明:从2000年以来,车尔臣河绿色走廊河湖湿地面积呈现出先增加后减少再增加的特点,其中2005年和2010年为峰值年份,河湖湿地面积分别为141 km2和393 km2;空间上呈现出不规则的区域变化特点。结合气象、水文和经济统计等数据,定性和定量分析了影响河湖湿地变化的主要原因,其中气温、降水量是导致河湖湿地增加的最主要的原因,而耕地扩张、经济的发展等人类活动起到消极的作用,但从整体趋势看影响较小。

River green corridor is a narrow barrier region along an inland river in arid region,it has two remarkable characteristics,one is that the soil moisture content in the corridor is higher than that in surrounding desert,and the other is that the landscape types are quite different from those in around environment.As an important landscape type in river green corridor in arid region in northwest China,marsh plays an important role in climatic regulation,water conservation and purification,maintenance of biological diversity,etc.The Qarqan River has the highest annual runoff volume in the southeast Tarim Basin and maintains the entironment of the green corridors in the east Taklimakan Desert and along the Tarim River.Because of its dramatic change,the river-lake marsh change in the green corridor along the Qarqan River attracts more and more attentions in recent years.So we monitored the dynamic change of the river-lake marshes using multispectral RS images from different satellites,such as Beijing-1,HJ,CBERS-2 and Landsat TM during the period from 2000 to 2010.The results show that the area of the river-lake marshes was enlarged at first,then it was reduced and followed by enlargement again since the year of 2000,and the monthly variation was also distinct in 2010.The monitoring area was 141 km2 in the year of 2005,and it was enlarged to 393 km2 in the year of 2010.Moreover,the meteorological,social and economic data,such as annual temperature,annual precipitation,annual cultivated land area and annual GDP in Ruoqiang County and Qiemo County in recent 50 years,were analyzed,and the correlations among the annual runoff volume of the Qarqan River and these factors were computed using quantitative analysis.The quantitative analysis was combined with the statistic data of glacier change in the Muztag Mountain during the period from 2000 to 2010 after analyzing the RS data and the water conservancy policy of Xinjiang government at all levels.The main causes resulting in the river-lake marsh change could be summarized as follows： Climate change was the key factor bringing about the river-lake marsh increase and the entironment maintenance in the green corridor of the Qarqan River,and temperature increase resulted in the glacier melting and the increase of annual precipitation and water resources supply.The increasing human activities,such as the expansion of cultivated land and economic development,require more water resources but result in the reduction of river-lake marshes.However,the implementation of the projects of water conveyance for saving the ecology and the water conservancy policy reduced these negative impacts.