松花江流域土地利用格局时空变化分析

为了在流域尺度上揭示21世纪最初10年松花江流域的土地利用变化的方向和强度，笔者基于2000年、2005年和2010年3期Landsat ETM卫星遥感数据，对松花江流域土地利用信息进行提取，并通过对比各子流域在不同时间序列上的差异揭示流域土地利用空间格局和时空变化。结果表明：2000—2010年，流域内湿地面积严重萎缩，其中嫩江水系湿地减少的最为明显。建设用地的面积显著增加，且3个子流域的建设用地面积均呈增加的趋势，其中第二松花江增长的速度最快，2010年比2000年增加了11.52%。整个流域的耕地面积稍有增加，但空间差异明显，表现为嫩江子流域耕地面积显著增加，而松花江干流和第二松花江流域耕地面积减少。在流域尺度上，土地利用转化过程中湿地-耕地、耕地-建设用地的转换较为剧烈，林地具有相对较高的保留率。空间上，土地利用转化强度较大的主要是嫩江中下游平原区和松花江干流下游入河口的平原地区，嫩江子流域各地类间的交叉转换频繁，且各1级地类内部的转化也较多，而松花江干流的转化主要在个别地类。

Spatial-temporal Variation of Land-use in Songhua River Basin

In order to uncover the change direction and extent of land use in Songhua River Basin in the first decade of 21th century at larger scale, the author analyzed land-use characteristics in Songhua River Basin using remote sensing (RS) maps of 2000, 2005 and 2010, respectively. Based on RS-derived maps, three change matrices were constructed for detecting land-use change between 2000 and 2005, between 2005 and 2010, 2000 and 2010 through overlay analysis. Three sub-basins were compared during different time periods to analyze spatial pattern and spatial-temporal variation of land use in the basin. The outcomes indicated that wetland greatly decreased slightly from 2000 to 2010, especially in Nen River. In contrast, land for construction greatly increased in the same period, and all three sub-basins present the trend of increasing, especially which of the Second Songhua River, increased by 11.52%. Farmland slightly increased from 2000 to 2010, but significant different were identified among three sub-basins. Farmland in Nen River obviously increased, but decreased in two other sub-basins. The dynamic conversion process of land use was dominated by wetland-cultivated land and cultivated land-construction land. The forestland had relative high retention rates. In spatial scale, the types of land use mainly were changed in the upstream plains of Nen River and downstream plains of Songhua River mainstream. The results also indicated that: the cross conversion in the Nen River frequently occurred among the types of land use, and a large part of internal conversion in the Ⅰ categories of land use had happened. But conversion occurred among only a few the types of land use in the Songhua River mainstream.