密云水库流域2000-2005年植被覆盖度变化监测

植被是生态系统最重要的组成部分,而植被覆盖度是衡量地表植被状况的一个最重要的指标,是生态系统健康评价的前提和必要的基础。文章利用2000和2005年2个时相的Landsat 7 ETM+遥感影像为数据源,以BP神经网络法为植被覆盖度估算模型,计算了密云水库流域内不同时期的植被覆盖度,生成了该流域2个时相内的植被覆盖度图,以此分析密云水库流域植被覆盖度的时空变化。结果表明,从2000-2005年,密云水库流域内除无植被覆盖类型外(即水域部分),其余土地利用类型的植被覆盖度都呈增加趋势,其中以沙质地和耕地最为明显,分别增长了29.5%和27.3%,并且密云水库流域的平均植被覆盖度不高,尤其西部地区植被覆盖度较差,水土流失和土地沙化情况比较严重。

Dynamic Analysis of Vegetation Coverage Change in Miyun Reservoir Basin from 2000 to 2005 Based on Remote Sensing

Vegetation includes all plant communities that cover the earth surface.Vegetation fraction is the most important index to scale the status of the vegetation of the region so the vegetation is the composition and the function body of ecological system.Vegetation coverage in different land use types of Miyun Reservoir Basin were calculated based on remote sensing images(Landsat 7 ETM+ images) in 2000 and 2005 by employing BP Neural Network method,and the vegetation coverage maps of different periods were generated to analysis the temporal change of vegetation coverage of Miyun Reservoir Basin.The results showed that,from 2000 to 2005,the vegetation coverage of every land use types were increased except the water area,and especially for the sand land and arable land,the growth were 29.5% and 27.3%,respectively.And the average vegetation coverage is not high in the Miyun Reservoir Basin,especially in the western region,the vegetation coverage is poor,and the soil erosion and land desertification situation is more serious.