以覆盖广州市的4个时相(1990、1995、2000和2005年)的TM遥感影像为数据源,经大气辐射校正,获得植被指数的计算模型,估算广州市域范围内的植被覆盖度,分5个等级研究植被覆盖度等级结构特征及其时空分异。结果表明:1990年至1995年间,广州市植被覆盖度下降幅度较大;植被覆盖等级结构也表明植被状态明显向不利于城市生态环境的方向变化。2000年至2005年间,植被覆盖度有所增加,等级结构也显示植被覆盖度有逆转的趋势。植被覆盖度变化幅度相对较大的是中心城区以外的新区,表明城市向郊区不断扩展。 

Vegetation index model was constructed based on TM image by atmospheric radiation correction in Guangzhou on 1990, 1995, 2000 and 2005, and vegetation fraction of Guangzhou was calculated. The vegetation fraction was divided into five grades. Grading structures and temporal-spatial characteristics of vegetation fraction in Guangzhou were analyzed. The results showed that grading structure of vegetation fraction in Guangzhou and each district occurred disadvantageously changes tourb an ecological environment from 1990 to 1995 due to continuous decrease of vegetation fraction. From 2000 to 2005, grading structure was improved lightly with the slight increase of vegetation fraction in studying area. Result indicated that changing extent of vegetation fraction was less in the centre than that in the suburb of Guangzhou, it also revealed that the city was expanding to suburb.