1982-2013年基于GIMMS-NDVI的新疆植被覆盖时空变化

利用美国国家航天航空局（NASA）全球检测与模型组（Global Inventor Modeling and Mapping Studies，GIMMS）的归一化植被指数数据（NDVI）和英国东英格利亚大学气候研究所（Climate Research Unit，CRU）全球气温降水数据（1982至2013年），研究新疆1982-2013年植被覆盖格局的时空变化。运用一元线性回归法分析近32年来新疆NDVI变化趋势；运用Theil-Sen median与Mann-Kendall检验研究新疆NDVI格局及趋势特征；并将检验的结果和Hurst指数的结果相结合，研究新疆NDVI格局的可持续性特征。研究表明：（1）新疆植被覆盖在空间分布上差异明显，其中北疆优于南疆，西北优于东南；（2）近32年来新疆年NDVI均值在0.10-0.12之间波动，且存阶段变化性；（3）新疆植被改善趋势的区域占总面积的25.89%，轻微退化的区域占总面积的18.00%；（4）从可持续性来看，新疆大部分地区植被变化将保持现在的趋势，但局部地区具有反持续性，持续性改善的面积占全疆总面积的24.39%，持续性轻微退化的区域占15.73%，另外59.88%为严重退化和未来变化趋势无法确定区域。开展NDVI空间格局的变化研究，对于干旱区新疆来说具有重要的理论和实际意义。

Assessment of spatio-temporal variations in vegetation cover in Xinjiang from 1982 to 2013 based on GIMMS-NDVI

The aim of this study was to adopt the Normalized Difference Vegetation Index (NDVI) data provided by the Global Inventor Modeling and Mapping Studies (GIMMS) of NASA and combine them with the global temperature and precipitation data supplied by the Climatic Research Unit of East Anglia University (CRU) in order to study vegetation coverage patterns in Xinjiang from 1982 to 2013. The linear regression method was used to study the trends of the changes in NDVI in Xinjiang over the last 32 years. The Theil-Sen median slope trend analysis and the Mann-Kendall test were also used to study the patterns and trends of NDVI in Xinjiang. The results of these analyses and of the Hurst index to determine the sustainability characteristics of NDVI patterns in Xinjiang show that (1) from the point of view of spatial distribution, the vegetation cover in the North and the South is significantly different. Coverage in the north is better than that in the south, and that in the northwest is superior to that in the southeast; (2) when viewed over time, the annual mean value of NDVI over the last 32 years in Xinjiang is between 0.10 and 0.12. An observable change in phase exists. (3) The vegetation distribution pattern reveals that 25.89% of the total area of Xinjiang shows a trend towards improvement in vegetation cover. Degradation in the area under vegetation accounts for 18.00% of the total area in Xinjiang. Overall, NDVI trends remain relatively stable in Xinjiang. (4) From the point of sustainability, most of the changes in vegetation cover maintained the development trends that are currently observed, with anti-continuity in some areas. Areas showing a robust trend towards improvement accounted for 24.39% of the total area in Xinjiang, and the areas that continue to degenerate account for 15.73%. Additionally, 59.88% of the total area in Xinjiang is affected by serious degradation of vegetation and uncertain development. Research on the changes in NDVI spatial patterns in Xinjiang has theoretical and practical significance for this arid region.