基于Landsat-8影像数据的北京植被覆盖度时空特征与地形因子的关系

Relationship between temporal and spatial characteristics of vegetation coverage and topographic factors in Beijing based on Landsat-8 image data

以北京市为研究区,通过像元二分法模型,基于Landsat-8影像,反演北京市2014年4月、2021年4月的植被覆盖度;并根据DEM数据,计算研究区的坡度、高程数据,将植被覆盖度与坡度、坡向、高程进行空间叠加分析,研究植被覆盖度时空特征与地形因子的关系。研究结果表明,北京市坡度较小的区域以中低植被覆盖区为主,随着坡度的变大,较高植被覆盖区的面积增加;坡向对于植被覆盖度的影响较小;高程较低的区域植被覆盖度较低,当高程增加到适合植被生长的范围时,植被覆盖度也随之增加。2021年4月北京市植被覆盖度相比2014年4月有了较大提高,表明这7年间生态建设取得明显成效,生态环境得到明显改善。

Based on landsat-8 images,the vegetation coverage of Beijing in April 2014 and April 2021 was retrieved by using the pixel dichotomy model.Data of slope and elevation in the study area were calculated on the basis of DEM data,and spatial superposition analysis of vegetation coverage with slope,aspect and elevation was carried out so as to study the relationship between temporal and spatial characteristics of vegetation coverage and topographic factors.The results show that the area with lower slope is dominated by middle and low vegetation coverage,and the area with higher vegetation coverage increases with the increase of slope.Slope aspect has little effect on vegetation coverage.Areas with lower elevations have lower vegetation coverage,and when elevations are increased to a range suitable for vegetation growth,vegetation coverage also increases.The vegetation coverage in Beijing in April 2021 was significantly higher than that in April 2014,indicating that the ecological construction in Beijing has achieved obvious results and the ecological environment has been significantly improved in the past seven years.