近15年中亚及新疆生态系统水分利用效率时空变化分析

Spatial and temporal variation analysis of ecosystem water use efficiency in Central Asia and Xinjiang in recent 15 years

基于一元线性回归法和Mann-Kendall检验方法,使用2000-2014年遥感数据,分析15年中亚五国及新疆GPP、ET、WUE的空间格局变化及趋势特征,并将参数检验结果相结合进行分类,分析WUE格局变化原因。研究表明:(1)GPP、ET、WUE在时间序列上无显著变化,WUE空间变化显著增加的区域为哈萨克斯坦北部、伊犁河谷和吉尔吉尔斯坦高山区,下降区域为新疆南疆和乌兹别克斯坦灌溉区。(2)WUE变化的主要土地覆盖类型是农田和草地,中密度人口区WUE变化较大。(3)WUE上升因降水增加、退耕导致的GPP增加,干旱胁迫下植被抗逆导致ET下降,WUE下降由于农作物类型转变及灌溉区不合理用水造成。开展中亚WUE空间格局变化研究,可为"一带一路"的顺利推进提供理论依据。

It is a great significance to study the carbon-water cycle which accurately evaluates the temporal and spatial variabilities of ecosystems water use efficiency （WUE）. In this study, the linear regression method and Mann-Kendall test were used to study the variabilities of spatial pattern of GPP, ET and WUE in the five Central Asian countries and Xinjiang from 2000 to 2014, then, the results of parameter tests of GPP, ET and WUE were combined and classified to analyze the causes of changes of WUE. The results showed that： （1） GPP, ET and WUE in the study area had no significant changes in time series. The spatial distribution of WUE had significant increases in the northern part of Kazakhstan, Ili Valley and alpine region in Kyrghyzstan, and had decreases in the south Xinjiang and the irrigated area of Uzbekistan. （2） The main land cover types which led to changes of WUE were farmland and grassland, and area with the medium density population had the great changes of WUE. （3） The increased WUE was resulted from the increased GPP and the decreased ET. The increased GPP was due to the increased precipitation and the Green for Grain Project, and the decreased ET was due to the response of vegetation to drought stress; the decreased WUE was mainly due to the changes of crops planted and unreasonable water use in the irrigated agricultural area in Central Asia and Xinjiang. This study on the basis of the variabilities of spatial pattern of WUE can provide a theoretical basis for the successful implementation of the ＂Belt and Road Initiative＂.