2000-2014年塔里木河干流的植被覆盖与蒸散发时空变化及其关系

Spatial-Temporal Variations in Vegetation Cover and Evapotranspiration and Their Relationship in Tarim River During 2000-2014

[目的]掌握塔里木河生态恢复的耗水规律,为生态水的合理规划和配置提供相应参考。[方法]利用MODIS的蒸散发(ET)和NDVI数据,及Mann-Kendall检验与Theil-Sen median趋势分析方法,选择阿拉尔—大西海子段作为代表区域,对塔里木河干流植被覆盖和蒸散发(ET)时空变化及其关系进行分析。[结果](1)塔里木河干流阿拉尔—大西海子段,NDVI及ET多年平均值分别为0.33,118.41 mm,ET及NDVI空间分异总体一致,ET分布受植被覆盖控制,总体表现为上段(阿拉尔—十四团)>下段(恰拉—大西海子)>中段(十四团—恰拉)。(2)年际变化上,NDVI与ET年时空变化差异明显,两者总体变化趋势相反,NDVI显著增加(ZC>1.96),ET非显著下降(-1.96<ZC<0);空间上,全区48.83%区域的NDVI发生降低,主要集中在中段,而ET的该比例则高达70.57%,广泛分布于中段及下段。(3)相对于NDVI,径流及水汽压,ET的年际变化与气温和降水相关性更好。[结论]塔里木河干流ET空间分布虽受植被覆盖所控制,但两者时空变化却差异明显。

[Objective]To understand the water consumption law in the ecological restoration of Tarim River,in order to provide references for the rational planning and allocation of ecological water.[Methods]Data including MODIS NDVI and evapotranspiration（ET）was collected in subsection of Alar-Daxixaizi in Tarim River from 2000 to 2014.Mann-Kendall method and Theil-Sen median trend analysis was used to investigate the spatiotemporal variations and the relationships between vegetation cover and ET.[Results]（1） In the Alar-Daxixaizi section of the Tarim River,the average value of NDVI and ET years was 0.33 and 118.41 mm,respectively.The spatial variation of the NDVI and ET was highly consistent,both were characterized as：upper reach（Alar—14 th regiment）〉down reach（Charla—Daxixaizi）〉middle reach（14 th regiment—Charla）.The spatial distribution of ET was controlled by vegetation cover.（2） For the inter-annual variability,the difference between the spatial variations of NDVI and ET was obvious,and the change trends of themwere generally reversed.NDVI increased significantly（ZC〉1.96）,while ET decreased（-1.96〈ZC〈0）.NDVI in 48.83% of the whole area decreased,which mainly located at the middle reach.The proportion of ET with decreasing trend accounted for 70.57% of the whole area,which was widely distributed in the middle and down reach.（3） Compared to NDVI,runoff and water vapor pressure,the annual variation of ET was more closely related to temperature and precipitation.[Conclusion]Although the spatial distribution of the ET in Tarim River was controlled by the vegetation cover,the spatiotemporal variations between them was distinct.