嘉陵江流域植被覆盖时空变化特征

TEMPORAL AND SPATIAL VARIATION OF VEGETATION IN JIALING RIVER BASIN

归一化植被指数(Normal Difference Vegetation Index,NDVI)能够反映植被的繁茂程度,可用来揭示环境的演化,并且能在全球变化研究中起到"指示器"的作用。目前利用NDVI研究植被变化多集中于陕西、甘肃、新疆等地区,对嘉陵江流域的植被变化趋势及其影响因素研究很少。利用线性相关分析方法分析GIMMS NDVI数据,借助于地理信息系统软件,分析嘉陵江流域植被覆盖的时空变化规律。研究结果如下:(1)嘉陵江流域在1982～2006年植被覆盖呈微弱上升趋势,与我国其它地区一致,但增长速率大小不一样;(2)嘉陵江流域植被覆盖明显优于黄土高原、西北地区,存在明显的空间差异,南部地区小于北部地区;(3)植被变化也存在空间差异,南部地区多呈增加趋势,而北部地区多呈减少趋势;(4)嘉陵江流域植被覆盖及其变化与气候变化和人类活动均有密切关系。基于分析,发现嘉陵江流域在人类活动和气候变化的双重影响下,环境向有利的方向发展。

Normal Difference Vegetation Index（NDVI） can represent the ground vegetation to some extent,which reflects the change of environment and global change.Currently,studies on vegetation change are mainly distributed in Shannxi Province,Gansu Province,Xinjiang Province etc.However,there are relatively few studies on temporal and spatial variation of vegetation and its impact factors in Jialing River Basin.Thus,with the support of GIS software,this study was to explore the temporal and spatial variation of vegetation and analyze the impact factors in Jialing River Basin using the GIMMS NDVI data and the linear correlation analysis method.The results are as follows：（1） In 1982～2006,the average NDVI in the whole basin gradually increased year by year.This was same with the other area,but their slope of linear regression equation was different.（2） The vegetation in Jialing River Basin was better than Loess Plateau and Northwest China.Spatial difference of vegetation was significant and NDVI in the southern district was less than northern district.（3） Spatial difference of vegetation variation was also significant.But slope of linear regression equation in the southern district was greater than northern district.（4） Spatial distribution of NDVI and its change in 1982～2006 was related to human activities and climate change.Based on these analyses,the results indicate that human activities such as soil and water conservation measures in the upper reach of the Yangtze River and climate change makes vegetation and environment better.