基于MODIS数据的广西植被覆盖度动态监测

Dynamic Monitoring of fractional vegetation cover change in Guangxi based on MODIS data

以MODIS-NDVI长时间序列数据为基础，利用像元二分模型对广西区内2001—2013年的植被覆盖度进行了估算，并采用转移矩阵的方法，分析了年份间覆盖度高低变化的方向。结果表明：13年间植被覆盖度呈波动式变化，在空间上的分布规律为东西部大于中部，越往中部植被覆盖度越低；区内植被覆盖度处于较高覆被，且总体呈增长趋势；13年间植被覆盖度变化大多处于稳定状态；2001～2007年和2007～2013年，各等级植被覆盖度以较低覆盖度向高一等级覆盖度转移为主，且正向转移大于负向转移。

Fractional vegetation cover （FVC） is a critical indicator for vegetation and the eco-environment. It is frequently as a basic input for hydrology, meteorology and water-soil protection studies at regional or global scales.Continuous 16-days composites of Moderate Resolution Imaging Spectroradiometer （MODIS）-Normalized Difference Vegetation Index （NDVI） images of 250 m spatial resolution were acquired for this study. Fractional vegetation cover of the Guangxi province was estimated using a dimidiate pixel method with its spatial-temporal changes in Guangxi from 2001 to 2013, and its change direction was analyzed by using transfer matrix. The results show that the change trend of vegetation was fluctuant,increased from west and east to center;the vegetation coverage in overall Guangxi was at a higher level in past 13 years, and tendency was increasing ;In terms of vegetation fraction intensity ,the vegetation fraction has been much stable for the past; From 1991 to 1999 and 2005 to 2010,the coverage transferring gradually from lower level to higher level ,and positive transformer was greater than the negative.