黑河流域植被叶面积指数时空变化特征

Spatio-temporal Changes of Vegetation Leaf Area Index in Heihe River Basin from 2001 to 2016

基于MODIS LAI、MODIS土地覆盖类型、平均气温、降水量、DEM数据,利用Slope趋势分析、相关分析法分析2001年~2016年黑河流域LAI的时空变化及其与气温、降水的相关性。结果表明,近16年,黑河流域LAI总体呈上升趋势,升幅为20.51%,LAI增大的区域主要集中分布在上游寒区试验区和中游人工绿洲试验区;16年间黑河流域中上游不同土地覆盖类型的植被状况逐渐改善,但下游地区呈退化趋势;黑河流域LAI与气温和降水的相关性几乎一致,但空间差异明显,中上游主要呈正相关关系,下游主要呈负相关关系。可见,2001年~2016年黑河流域植被LAI总体呈上升趋势,流域中上游植被状况不断改善,但下游植被逐渐退化。

Based on MODIS LAI,MODIS land cover type,average temperature,precipitation and DEM data,the slope trend analysis and correlation analysis method are used to analyze the temporal and spatial changes of leaf area index(LAI)in Heihe River Basin from 2001 to 2016 and its correlation with temperature and precipitation.The results show that,(a)in the 16 years the LAI of the Heihe River Basin has shown an overall upward trend with an increase of 20.51%,the areas where the LAI has increased are mainly distributed in the upper cold area test area and the middle reaches of the artificial oasis test area;(b)the middle and upper reaches of Heihe River Basin have different land coverage and the vegetation status of different types are gradually improved in the 16 years,but the lower reaches shows a trend of degradation;and(c)the correlations between the LAI and the temperature and precipitation in Heihe River Basin are almost the same,but the spatial difference is obvious,in which,the middle and upper reaches are mainly positively correlated and the lower reaches is mainly negatively correlated.It can be seen that the overall LAI of vegetation in Heihe River Basin shows an upward trend from 2001 to 2016.The vegetation conditions in the middle and upper reaches of the basin are continuously improved,but the vegetation in the lower reaches is gradually degraded.