| 张一驰,于静洁,乔茂云,杨宏伟.黑河流域生态输水对下游植被变化影响研究[J].水利学报,2011,42(7): |
| 黑河流域生态输水对下游植被变化影响研究 |
| Effects of eco-water transfer on changes of vegetation in the lower Heihe River basin |
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| DOI： |
| 中文关键词: 额济纳 生态输水 植被变化 归一化植被指数 （NDVI） |
| 英文关键词: Ejina basin environmental flow control vegetation changes Normalized Difference Vegatation Index（NDVI） |
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| 中文摘要: |
| 通过对2000—2009年的MODIS/NDVI序列分析，研究了黑河下游额济纳地区实施生态输水后该地区的植被时空变化格局。基于不同时空分辨率的遥感影像和实地考察资料，分析了形成植被变化空间差异的主要原因。研究结果表明： （1） 研究区内80.4 %的绿洲区植被和91.5 %的荒漠区植被呈恢复趋势。绿洲区内季节累积植被指数序列趋势度大于0.14a-1的区域都存在农田开垦或弃耕地复播现象；荒漠植被的显著恢复主要发生在西河中、下游和东河下游地区。（2） 研究区内19.6 %的绿洲区植被和5.1 %的荒漠区植被进一步退化，退化区主要分布在衬砌渠系两侧和一些干涸或径流减少的自然河流两岸，植被退化主要是乔木林的退化。（3） 大范围的植被恢复主要原因在于地下水环境的整体好转，以及生态保护措施的实施；地下水环境的整体好转取决于黑河中游来水量的增加和下游输水方案的实施。（4） 研究区内植被退化的直接原因在于目前输水方案实施后引起的局部地表水环境恶化。因此基于植被动态监测和局部植被对全局生态的重要性评价，确定合理的输水方案，对于区域生态环境演变进入
良性循环意义重大。 |
| 英文摘要: |
| The ecological water transfer has been implemented in the Heihe River basin since 2001 in order to restore the degraded ecosystem，especially in its lower reach，Ejina basin. In this study，the temporal-spatial pattern of vegetation change in Ejina basin was investigated through the trend analysis of MODIS NDVI time series from 2000 to 2009，and its causes were discussed based on the multi-scale remote sensing images and field investigations. The results show that：（1） The vegetation in 80.4% of oasis regions and 91.5% of desert regions presented an increasing or recovery trend with increasing magnitude larger than 0.14a-1mainly resulted from cultivated lands reclamation and the recovery of desert vegetation largely took place in the middle and lower reaches of the Ejina basin. （2） The vegetation in 19.6% of oasis and 5.1% of desert regions showed a decreasing or degrading trend，mainly in the area where water reduced or rivers diminished and along artificial concrete canals with degradation largely occurred in forest regions. （3） The vege-tation recovery mainly resulted from the regional improvements of groundwater environment and adoption of vegetation protection counter-measures and the improvements of groundwater environment were due to the increasing of river stream from the middle reach of Heihe river and current water-transfer strategy. （4） The vegetation degradation directly resulted from the deterioration of local surface water environment caused by current water-transfer strategy. It is conclucled that a rational water-transfer scheme based on the monitoring of vegetation dynamics and the assessment of the effect of local vegetation on regional ecological environment should be made to improve the ecological environment recovery. |
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