塔里木河流域综合治理生态要素变化的遥感分析

Analysis of Ecological Elements of Comprehensive Harnessing in Tarim River Basin Using Remote Sensing

采用多种类、多时相遥感数据对塔里木河流域综合治理后的耕地变化和干流绿色走廊带的植被、沙质荒漠化和盐碱质荒漠化等主要生态要素进行了动态监测,结果表明:(1)1999-2008年间,流域耕地面积逐步扩大,从167.17万hm2增长到207.51万hm2。其中,塔里木河干流区耕地面积增加最快,叶尔羌河、开都河-孔雀河与和田河三流域稳步增加,而阿克苏河流域耕地面积先增加,后减少。除阿克苏河流域外,塔里木河流域等其他三流域和塔里木河干流,在2004-2008年间的面积增长速度明显大于1999-2002年和2002-2004年两个时段。(2)2002-2004年间,塔里木河干流绿色走廊带生态环境明显改善,主要表现为植被覆盖度的提高、沙质荒漠化土地面积的减小和强度减弱、盐碱质荒漠化土地的强度减弱等。耕地面积的大幅度增加引起的灌溉用水量的增大,对长期采用输水实现塔里木河的生态功能恢复具有长期性制约作用。

The Tarim River Basin,especially the downstream area of it is one of the ecologically fragile areasin China.Based on technologies of multi-type,multi-temporal remote sensing imagery,key ecological elements,that is,cultivated land changes in whole Tarim River Basin,the vegetation,sandy and salinized desertification in the green corridor zone of Tarim River mainstream were monitored from 1999 to 2008,after the implementation of comprehensive harnessing engineering for the whole Tarim River Basin.The investigation results show that the ecological environment in the green corridor zone of Tarim mainstream was conspicuously improved,mainly appearing as the rise of vegetation cover rate,the reduction of sandy desertification land area and the weakening of intensity of sandy and salinized land.On the other hand,the cultivated area in the Tarim River Basin significantly increased from 1999 to 2008,which reached 40.34×10 4 hm 2,for 24.13%.Among the whole basin,the cultivated area of the mainstream area increased most quickly.The growth rate of cultivated area of whole basin from 2004 to 2008 is significantly higher than those of the two periods from 1999 to 2002 and from 2002 to 2004.Moreover,the characteristics of sandy and salinized land in upstream of the main channel showed an increase in area of 2.69×10 4 hm 2 and a reduction in increase rate from 2002 to 2004.And sandy desertification land area decreased 1.20×10 4 hm 2 in the same period in lower reach of the basin.Vegetation cover rate of the whole basin apparently increased,especially the surrounding area of the Taitema Lake.Although the ecological environment presented an somewhat improvement after the implementation of comprehensive harnessing in the whole basin,the ecologically fragile environment need long-term supply of water resource and continuous concern from the whole society.The increase of irrigation water resulting from the substantial increase of cultivated area could undertake a long-term potential restraining effect on the harnessing of ecological functions of the Tarim River.