基于SPOT/NDVI华北地区植被变化动态监测与评价

Monitoring and assessment of vegetation variation in North China based on SPOT/NDVI

利用1998-2011年SPOT NDVI数据反映华北地区植被覆盖变化情况,结合该地区土地覆盖数据以及1982-2011年84个气象站点的气温和降水数据,分别从时间和空间两个方面对其进行植被动态监测与评价,并简要分析其变化原因。结果表明:1)从时间上来看,华北地区NDVI在1998-2011年总体呈增长趋势,表明该地区植被覆盖情况整体上得到改善,其中,森林和农田NDVI增长最快;2)从空间上来看,华北地区地表植被覆盖得到改善的区域比退化区域面积要大,其中,森林和农田的恢复效果最为明显,而灌丛、草地、沙漠退化面积均超过改善面积,表明华北地区水土流失和荒漠化现象依然严峻;3)在华北地区气候长期趋于暖干化的背景下,华北植被变化与降水变化关系比与气温变化关系密切,表明植被覆盖变化受降水影响较大,此外,人类活动也是引起植被覆盖变化的重要驱动因子。

SPOT NDVI data from 1998 to 2011 were adopted to reflect the characteristics of vegetation coverage change in North China.The change was dynamically monitored and assessed from the time and spatial aspects combined with temperature and precipitation data between 1982-2011 of 84 meteorological sites and land cover data.And the change reasons were analyzed in brief.The results showed as follows：（1） In the time dimension,an increase of NDVI was found in the whole North China from 1998 to 2011,which indicated that the vegetation was recovering well in this area.And particularly the NDVI of forest and farmland increased most rapidly.（2） In the spatial dimension,the greening area was larger than the degraded area in the whole North China,and the vegetation of forest and farmland recovered most obviously,while the degrade area of bush,grassland and desert was larger than their greening area,which meant that the degree of water and soil loss and desertification of North China was still serious.（3） There was a positive correlation between NDVI and precipitation under the background of North China whose climate is increasingly warming and drying for a long time.Vegetation change of North China was better correlated with precipitation than temperature,which indicated that the sensitivity of vegetation change to precipitation was higher during these years.Besides climatic factors,human activities were also important factors making the vegetation change.