基于SPOT数据的海河流域植被覆盖度变化图谱特征

Spectrum characteristics of vegetation coverage change based on SPOT data in Haihe River Basin

为了从时空结合的角度探讨1999—2013年15年间海河流域植被覆盖的变化轨迹和特征,基于SPOT/NDVI数据,运用图谱分析法对海河流域的植被覆盖度变化进行时空分析.结果表明:(1)1999—2004年的植被覆盖度变化图谱以植被覆盖度等级转好的图谱单元为主,其空间分布较集中,而植被覆盖度转差的图谱单元较少且空间分布较分散.(2)2004—2009年植被覆盖度变化的总面积减少;以植被覆盖度转差的图谱单元为主,其空间分布由上一阶段分散变为集中,而植被覆盖度转好的图谱单元在空间上由上一阶段集中变为分散.(3)2009—2013年,植被覆盖度变化的总面积得到回升,空间差异上植被覆盖度的变化与第1阶段相似,与第2阶段相反,皆以植被覆盖度转好的图谱单元类型为主,空间分布较集中,而植被覆盖度转差的图谱单元空间分布较分散.(4)1999—2013年,植被覆盖度变化图谱模式以稳定型主,说明植被覆盖度较稳定,其次是前期转换型和连续转换型,具有明显的时间阶段特征,所有图谱模式以中、高等植被覆盖度相互转换为主.研究结果可以及时准确地反映该流域植被变化状况,为海河流域生态环境保护提供科学指导.

In order to discuss the change trajectories and characteristics of vegetation coverage in Haihe River Basin from1999 to 2013,under temporal and spatial integration aspect. Spatial-temporal distribution characteristics of vegetation coverage change were analyzed combining with the spectrum analysis based on the SPOT/NDVI data. The results indicate that ：（1）In 1999—2004,spectrum units mainly are that vegetation coverage grade are better,its spatial distribution is relatively concentrated,and the spectrum unit of vegetation coverage slip is less and the space distribution is more dispersed.（2）In 2004—2009,the total area of vegetation cover change are decreasing. Spectrum units mainly are that vegetation coverage grade are slip,and the spatial distribution is changed from dispersed to concentrated. However in space the spectrum unit of vegetation coverage better are changed from focused into dispersion.（3） In 2009—2013,the total area of vegetation cover change is picked up,and on the spatial difference vegetation coverage change is similar with vegetation coverage change in 1999 —2004,contrary to the second stage. Spectrum units mainly are that vegetation coverage grade are better,its spatial distribu-tion is relatively concentrated,and the spectrum unit of vegetation coverage slip is less and the space distribution is more dis-persed.（4）For the mode of spectrum change,the stabilization are primary,followed by the conversion of the type and the continuous conversion,and have obvious time phase. The vegetation coverage change spectrum pattern are the middle and high vegetation cover conversion. These findings will help reflect the variety of vegetation coverage in time,and provide scientific guidance for the ecological environment protection and sustainable development of Haihe River basin.