中国北方地区植被覆盖度遥感估算及其变化分析

Fractional vegetation cover estimation in northern China and its change analysis

为了分析中国北方地区2000年之后植被覆盖度的时空分布及其变化,利用MODIS光谱反射率数据计算归一化植被指数,采用像元二分模型对中国北方地区2000—2012年植被覆盖度进行定量估算,分析研究区13 a间植被覆盖度的时空变化特征。研究结果表明:植被覆盖度年内变化特征体现在最大植被覆盖度一般出现在7和8月份,与中国北方地区植被的生长季相一致;整个中国北方地区年最大植被覆盖度呈现缓慢增长的趋势,其增长速率为每年0.2%;年最大植被覆盖度变化的空间分布具有较大差异,其中东北、华北和黄土高原等三北防护林工程建设区的年最大植被覆盖度有较明显的增长。

The aim of this study is to analyze the spatial-temporal pattern and change of fractional vegetation cover （FVC） in northern China since 2000. FVC of northern China from 2000 to 2012 was estimated using dimidiate pixel model based on the normalized difference vegetation index （ NDVI） calculated by MODIS spectral reflectance data. The FVC change trends and characteristics of the study area during the 13 years were analyzed. The inner annual FVC change trend in northern China indicated that the maximum FVC generally appeared in July or August, which was consistent with the vegetation growth season. The maximum annual FVC showed a slightly increase trend in the whole study area, and the annual increase rate was 0. 2%. However, the spatial distribution of maximum annual FVC change trend had great differences. The typical regions of the Three-North Shelter Forest Region such as Northeast China, North China and Loess Plateau region had an obviously increase in maximum annual FVC.