基于MODIS/EVI的额尔古纳河流域植被变化分析

Assessment of vegetation cover change in the Argun basin based on MODIS/EVI

选取额尔古纳河流域2000—2009年的5—9月间的共80个时相的MODIS-EVI数据,以每年EVI最大值和平均值为指标对额尔古纳河流域研究区的植被变化趋势进行分析。分析结果表明:整个区域的植被指数总体呈下降的趋势,其中显著下降的面积约15 197km2(10.05%);显著增加的面积约为2 733km2(1.81%)。根据区域土地利用分类数据以及DEM数据的分析发现,植被呈显著减小趋势的区域主要分布在海拔较低的湿地和海拔较高的林地,林地EVI指数呈显著下降意味着其发生了大面积的退化,结合1979—2008年4—9月的径流分析发现,由于近年来流域径流量的明显减小所以湿地EVI指数呈显著下降也意味着它也发生了大面积的退化。额尔古纳河流域气温逐年升高、降水量减少、蒸发量增加等气候条件的变化,是该区域植被指数下降的主要原因。

This paper selected 80 periods of MODIS-EVI data of May to September of each year from 2000 and 2009 in the Argun Basin.The maximum and average of EVI of each year were chosen as indicators to analyze vegetation changing trends.Three types of trend were observed-null,positive and negative.Over the study area the negative area reached 15 197km2（10.05%） and the positive area was 2 733km2（1.81%）.Based on a land cover map and DEM data,the analysis has shown that the negative areas are mainly located at low elevation wetland and high elevation forest.The forest and wetland negative trend suggests a vegetation cover degradation.Increase in the temperature and evaporation and decrease in precipitation of the Argun Basin are regarded as the main reasons of the negative trend.