南美洲的地表水体制图研究

采用Landsat TM遥感影像,辅以MODIS数据产品,应用像元的分类方法,选用水体指数AWEI（Automated Water Extraction Index）提取水体,估算了2011年南美洲陆表水域总面积。同时,在南美洲各大气候带内监测其典型水域的年内季节性面积及其变化。研究表明,南美洲陆表水域总面积为30.5×10⁴ km²,水域率为1.69%,主要集中分布在亚马逊河流域、巴拉那河流域,以及南部巴塔哥尼亚高原。南美洲共计有湖泊9579个,总面积为14.2×10⁴ km²,占水域总面积的46.42%;河渠总面积达15.7×10⁴ km²,占水域总面积的51.56%;水库坑塘总面积达6144.8 km²,占南美洲地表水域总面积的2.01%。从各大气候区看,热带地区的水域面积明显受到旱雨季的影响,其中,热带沙漠气候带内水域的干湿季变化最为明显;温带地区的水域面积变化相对较小,但有明显的四季之分;高原山地气候区由于其独特的气候特征,水域面积变化较小;亚热带季风性湿润气候和地中海气候区内的水域面积季节性波动很小,但是冬夏2个季节变化明显。从南美洲各国家看,水域面积最大的国家为巴西（14.7×10⁴ km²）,占南美洲水域总面积的48.17%,水域率为1.72%;其次为阿根廷（3.4×10⁴ km²）,占南美洲水域总面积的11.24%,水域率为1.23%;委内瑞拉的水域率最大（3.08%）。

Research on South America Surface Water Mapping

As an important land cover type of Earth's surface, the surface water has a huge effect on the water cycle, climate change, environment and human activities. Thus, it is significant to analyze the distribution of the surface water and its change trend in time series. This study focuses on the use of the Automated Water Extraction Index (AWEI) to quantitatively evaluate the total surface water area in South America based on Landsat TM imagery and the MODIS digital product acquired in 2011. Meanwhile, the seasonal area fluctuation of the surface water in each typical climatic zone is monitored and the resultant data is used to analyze why the fluctuation occurred. The known data show that the total area of surface water in South America, mainly concentrated in the Amazon River basin, the Parana River basin and the Patagonia Plateau, is 305,000 km² and the water rate is 1.69%. Based on our study, the number of lakes in South America is 9,579 while the total area is 142,000 km², which takes 46.42% of the total area of surface water; the area of waterways is 157,000 km², which takes 51.56% of the total area of surface water; and the reservoirs and ponds, which takes 2.01% of the total area surface water, is 6144.8 km². From the perspective of climate zones, the area of surface water in the tropical zone of South America was influenced obviously by the change of rainy seasons, and within which the tropical desert climatic zone was the most affected one; in the temperate zone, the area of surface water didn’t change a lot because it has distinct seasons; in the plateau mountain climate zone, the area didn’t change a lot due to its unique climate feature; in both subtropical monsoon wet climate zone and Mediterranean climate zone, the surface water hardly changed with seasons but it exhibited obvious variations in winter and summer seasons. From the perspective of countries in South America, Brazil has the largest area of surface water (147,000 km²) which takes 48.17% of the total area of surface water in South America and its water rate was 1.72%; Argentina has the second largest area (34,000 km²) which takes 11.24% of the total surface water area and its water rate was 1.23%; while, Venezuela has the largest water rate (3.08%). The surface water in each typical climatic zone of South America has seasonal area fluctuation on several levels, which may relate to climate change and human activities. Further studies are needed to explain this issue in future.