河南省植被覆盖度的时空变化特征

Temporal and Spatial Variation of Vegetation Coverage in Henan Province

利用1990年和2000年两期河南省TM遥感影像数据,通过对数据进行大气校正、辐射校正、图像镶嵌、图像分割等数据预处理工作,然后计算出每期影像的NDVI(归一化植被指数),利用像元二分模型把植被指数转换为植被覆盖度,并对这两个时期的植被覆盖度进行对比分析。结果表明,从植被覆盖度的时间变化上看,10年间极低与低植被覆盖度类型的面积减少,但是中、中高和高植被覆盖度类型的面积明显增加,这说明河南省的植被覆盖总体上是好转的;从植被覆盖度的空间变化上看,豫北濮阳、鹤壁,豫东商丘,豫南驻马店等区域植被覆盖度增长明显,而豫西平顶山、三门峡及商丘南部植被覆盖度减少变化明显。

Based on two TM remote sensing image data of Henan Province in 1990 and 2000, by performing data preprocessing of atmospheric correction, radiometric correction, image mosaic and image segmentation, NDVI（Normalized Difference Vegetation Index） in each image were calculated. The vegetation index was converted to vegetation coverage through dimidiate pixel model, and the two images of vegetation coverage were compared and analyzed. The results showed that, in terms of time variation in vegetation coverage, very low and low vegetation coverage degree type area decreased during the past 10 years, while middle, upper-middle and high vegetation coverage degree type area were significantly increased, indicating that the vegetation coverage in Henan province was generally improved. In terms of time variation in vegetation coverage, Puyang,Hebi, Shangqiu, Zhumadian visibly increased, while Pingdingshan, Sanmenxia and southern Shangqiu obviously reduced.