重庆市植被指数与高度/坡度的关系研究

On Relationship Between Vegetation Index and Height/Slope in Chongqing

为了明确并量化重庆市植被指数(NDVI)与地形的关系,利用重庆市2010-2013年中分辨率成像光谱仪(Moderate-resolution Imaging Spectroradiometer,以下简称MODIS)250m分辨率的16d合成植被指数产品,并合成月和四季植被指数(植被指数为扩大100倍的结果),将植被指数按高度和坡度分别分成6个高度特征区和5个坡度特征区,分析植被指数与高度、坡度的关系,并建立关系式.结果表明:1植被指数与地形的关系受月份和季节的影响明显.6-9月逐月NDVI及夏季平均(6-8月均值)NDVI随高度的增加持续增大;10-12月逐月NDVI、1-5月逐月NDVI份及春季(3-5月)平均NDVI、秋季(9-11月)平均NDVI、冬季(12月、次年1-2月)平均NDVI,都随高度增加基本呈现出先增后减的趋势,增、减转折点出现的高度在冷的月份/季节降低,在暖的月份/季节会有所升高.植被指数随坡度的变化趋势相对明显和单一,在所有月份和季节里,基本呈现出随坡度增加而增大的趋势.2植被指数随高度/坡度增加呈现出来的增大趋势随高度/坡度增加逐渐减小.3植被指数与高度之间都基本遵循很好的二项式关系,并且大部分通过了p=0.001的相关检验;与坡度之间遵循二项式和幂函数关系,且基本都通过了p=0.001的检验.

In order to clarify and quantify the relationship between NDVI and topography in Chongqing, MODIS-250m 16 days NDVI from 2010s to 2013s has been used to synthesize monthly and seasonal NDVI enlarged 100 times. And then the NDVI has been divided into 6 height districts and 5 slope districts. The relationship between NDVI and height/slope has been analyzed and the equations of NDVI and height/ slope been established. The results show that, 1） Different month and season have obvious effect on the relationship between NDVI and height/slope. The value of NDVI in months 6 - 9 and summer continued to increase with the increase of altitude. While NDVI increased firstly then decreased with the increase of height in months 10 -12 and 1 - 5 , seasons of spring, autumn and winter. The turning height of the NDVI value decreased in cold month/season and increased in warm month/season. The trend was relatively obvi-ous and simple with increase of slope that was the NDVI monotonically increased with slope increasing. 2） The increasing trend of NDVI with height/slope increasing gradually decreases. 3） There was good bino-mial relationship between NDVI and height and most of these passed correlation coefficient test（P〈C0. 001）.There was binomial and exponential relationship between NDVI and slope and most of the equations pas-sed correlation coefficient test（P〈C0. 001）.