基于Landsat TM 数据的若尔盖县LUCC 时空特征研究

若尔盖县是世界著名若尔盖湿地的主要组成部分, 是青藏高原高寒生态系统的典型代表。基于1989 年、1997 年和2004 年3 期Landsat TM 影像的土地利用ö土地覆被分类结果, 运用地理信息系统空间分析方法和数理统计学方法, 深入分析了四川省若尔盖县近15 年来各土地利用/覆被类型尤其是草地和沼泽的数量和空间变化特征。结果表明: ①研究区主要土地利用与土地覆被类型为草地、沼泽、林地和裸地, 其中草地与沼泽面积逐步减少, 而裸地面积成倍增长。②通过建立研究区LU CC 幅度、LU CC 数量和空间变化模型以及趋势与状态指数模型, 很好的表现了研究区LU CC 的时空特征。从整个区域来看, 前期综合LU CC 趋势和状态指数为0. 37, 处于准平衡状态;后期小于前期, 为0. 23, 处于平衡状态, 整个时段其指数为0. 35, 为准平衡状态, 呈现双向转换态势。③定位分析了研究区LU CC 情况, 发现区域草地和沼泽退化相当严重, 而且前后两期退化区在空间上有所转移。

Spatial-temporal Characteristics of LUCC in Zoige County Using Landsat TM Sensor Data

As the most important part of Zoige wetland, Zoige county is a typical representation of alpine ecosystem in Tibetan Plateau. The LUCC characteristics of Zoige county in the past 15 years are investigated and analysed by using Landsat TM sensor data of 1989, 1997 and 2004 with themethod of geographic information system (GIS) and statistics. Themain results are as follow: ①Themain types of Land use/Land cover in research area are grassland, marsh, woodland and bareland. Since 1989, the area of grassland and marsh has been decreasing with bareland increasing rapidly. ②By establishing mathematical models in the range, quantitative and spatial dynamic change, trend and state index of LUCC, the spatial-temporal characteristics of LUCC can be deeply studied. In the period of 1989-1997, the trend and state index of the whole research area was 0. 37, which means the state was quasi-balanced. In the period of 1997-2004, the index was 0. 23 which is smaller than former period and indicate the state of LUCC was balanced. In the whole period (1989～2004) , the state of the research area LUCC was quasi-balanced with the transitional process in bi-direction. ③Through analyzing Land use/Land cover change spatially ,we found that grassland and marsh of this area degenerated sharply with the degraded area transferred spatially from the two periods.