2000-2013年塔里木河流域生长季NDVI时空变化特征及其影响因素分析

受塔里木河流域综合治理工程实施和近期气候变化的影响,流域植被覆被时空分布产生一定的变化,厘清植被覆被与流域气候变化及人类活动的关系可以为塔里木河流域生态维护与治理提供科学参考依据。为此,论文以NDVI为指示因子,运用趋势分析、R/S分析、偏相关分析以及残差分析等方法,分析了2000-2013年综合治理工程期间NDVI的时空变化特征,并探讨及区分降水、气温气候因子以及人类活动对植被覆被变化的影响范围和程度,结果表明：1）2000-2013年,塔里木河流域植被生长季NDVI总体呈现增加趋势,增加速率为0.8%/10 a,平原区增速明显高于山区;且开都河-孔雀河流域山区、塔里木河干流的上、中游部分地区呈现比较明显的退化趋势。与此同时,塔里木河干流下游生长季NDVI持续改善。2）山区植被覆被变化主要受气候变化的影响,其中温度是高山区植被生长的主要限制因子,温度的增加促进植被的生长;中低山区以及出山口平原地区植被生长季NDVI变化是降水和温度共同作用的结果,且主要受降水的影响。降水与植被生长季NDVI变化呈正相关,温度与植被生长季NDVI变化呈负相关。3）平原绿洲区植被生长季NDVI增加主要是绿洲灌区面积不断增加以及塔里木河流域生态治理工程对植被恢复的结果,人类活动是该区域植被生长的主要驱动力。4）塔里木河干流生态闸工程在恢复下游植被的同时,也在一定程度上影响了上、中游地区的用水,尤其是导致中游植被出现退化趋势,退化速率约为0.1%/10 a。相关部门应进一步加强水资源的合理配置,充分发挥生态闸工程的水资源调度调控作用。

Spatial-temporal Variation of Growing-season NDVI and Its Responses to Hydrothermal Condition in theTarim River Basin from 2000 to 2013

The spatial and temporal distribution of vegetation cover has undergone certain changes in the Tarim River Basin due to the impacts of comprehensive treatment project and recent climate change. Clarifying the relationship between the vegetation cover and the climate change as well as human activities can provide a scientific reference for ecological maintenance and management of Tarim River Basin. Hence, by using trend analysis, R/S analysis, partial correlation analysis and residual analysis, this study analyzed the spatial-temporal changes of NDVI in the growing season and distinguished the range and extent of the impacts of precipitation and temperature changes and human activities on vegetation cover change in the Tarim River Basin from 2000 to 2013. The results showed that: 1) The NDVI in the study area has been increasing with an average rate of 0.8%/10 a from 2000 to 2013. The changing rate in plains was significantly higher than that in mountains. The NDVI in growing season in the mountainous areas of Kaidu-Kongque River Basin and parts of the upstream and midstream of the Tarim River Basin presented obvious degradation trend. Meanwhile, NDVI in the downstream of the Tarim River Basin continued going up. 2) The vegetation cover change was mainly affected by climate change in mountain area and the temperature is the main determining factor. The increase of temperature promoted the growth of vegetation. The changes of the vegetation cover in middle-low mountains and the plain area of the mountain pass were the results of the combination of precipitation and temperature, and mainly affected by precipitation. The NDVI showed a positive correlation with precipitation and a negative correlation with temperature. 3) The increasing oasis irrigation area and the comprehensive treatment project for vegetation restoration led to the NDVI increase in the oasis. Human activities are the main driving force for vegetation growth in this area. 4) The ecological brake in the midstream of the Tarim River Basin restored the vegetation in the downstream, but it affected the water usage of the upstream and midstream to some extent. Especially for the midstream, the ecological brake led to the degradation of the vegetation with the rate of 0.1%/10 a. The relevant departments should further strengthen the reasonable allocation of the water resources and give full play to the role of the ecological brake for water resources regulation.