水情波动下2006-2011年塔里木河下游植被变化研究

由于开都-孔雀河来水量的减少,塔里木河下游生态输水量自2006年开始锐减,之后连续枯水3a,直至2010年来自上游的输水水头才重新到达塔河下游台特玛湖处。采用2006-2011年Landsat TM卫星遥感影像数据,对塔里木河下游区域进行了植被分类和覆盖度信息提取;在连续植被变化监测数据的基础上,研究了水情波动影响下的塔里木河下游地区植被时空变化格局,探讨了形成植被变化时空差异的主要原因。结果表明,2006-2011年植被覆盖面积总体上呈现先下降再升高的现象,其中灌木林地变化最为显著;2011年研究区植被覆盖度总体高于2006年,大部分区域的植被覆盖度呈缓慢增加趋势,覆盖度显著增加区域面积占2011年植被覆盖面积6.3%;生态输水量的变化是影响塔里木河下游植被生长与恢复的主导因素,大范围的植被恢复的主要原因在于地下水位的显著抬升,而地下水位的升降主要依赖于生态输水量的变化。

Changes of Vegetation Coverage Under Hydrological Fluctuations in Lower Leaches of Tarim River Basin

Due to the reduction of water flow from Kaidu-Kongque River since 2006,the ecological water conveyance in the lower reaches of Tarim River decreased sharply for three years until the waterflow reached into Taitema Lake in 2010.The paper studied on the spatial and temporal changes of vegetation coverage with continuous monitoring of the vegetation changing under hydrological fluctuations during 2006-2011by substracting the data of vegetation information through Landsat TM remote sensing image data in lower reaches of Tarim River Basin and explored the main reasons of the spatial and temporal variances of the vegetation changes.The results indicated that vegetation area decreased during 2006to 2009and then increased with the maximum area increase in shrub land;the overall vegetation coverage of the studied region was higher in 2011than 2006with a slow increasing in most of the area and a significant increased area only accounted 6.3%of the whole area in 2011;the change of water flow in the Tarim River is the dominant factor of vegetation growth and recovery in the area since it raised the groundwater that directly prompted vegetation recovery.