遥感方法研究珠江口近二十多年来土地覆盖的变化

土地覆盖变化是全球变化研究的重点之一，尤其是河口地区，对环境变迁十分敏感。对珠江口东部地区1979年的Landsat MMS、1990年Landsat TM和2000年Landsat ETM影像的土地覆盖分类，并进行对比研究表明，此间，总体水域面积和绿地（包括森林和耕地）面积减少，建筑区和裸露地面积增加。但不同区域土地覆盖类型变化有明显的区别，西部主要是由于沉积作用和围海造地，造成水域面积减少，且20世纪90年代围海造地速率比80年代要大得多。东部海域沉积作用不是主要因素，局部海岸可能还存在侵蚀作用。交椅湾区水域面积变化不大，岸线位置也基本稳定，而且80年代的水域面积有所增多，是由于陆地人工水塘增多的结果。蛇口区主要是由于港口码头等建设，导致水域面积减少，码头向海域延伸的结果，90年代明显加大了码头建设的规模和速度。

The Research of Land Cover Change in Recent Decades in the Pearl River Estuary by Remote Sensing Methods

Land cover change is one of the key content for research of global changes, especially in the estuary which is very sensitive for environmental changes. Three images of Landsat MMS in 1979, Landsat TM in 1990 and Landsat ETM in 2000 in the Pearl River Estuary, southern China, were classified for land cover in ERDAS IMAGINE, and the result were checked by referenced to higher resolution images of SPOT and IKONOS and topographic maps. It is suggested that water area and green area were shrinking in 1980s and 1990s, but construction and bare land area were increasing in the same periods. The change rate was increasing from 1980s to 1990s. The main changes in the eastern region were the water area shrinking mainly due to the sedimentation and reclamation. But sedimentation was not the main reason for shoreline changes in the eastern region. The water area in Jiaoyi Bay region was increase from 1979 to 1990, mainly due to the increase of fish-pond in the land area or some erosion in coast. The main changes of shoreline in Shekou region were its extension by the construction of harbours and other infrastructure in the coast, and the changes rate was higher in 1990s than in 1980s.