山区河流宽谷段坝区土地利用动态变化及其与河道关系——以南汀河下游坝区为例

采用ISODATA非监督分类方法,结合目视判读,对南汀河下游坝区1988年、1996年、2002年和2009年4期Landsat TM/ETM+遥感影像进行分类,以揭示研究区几十年来土地利用变化时空格局。基于遥感分类结果,运用单一土地利用动态度、综合土地利用动态度、土地利用转移率等指标,进一步分析了研究区土地利用变化强度与速率,以及土地利用变化强度与河道的关系。研究结果表明,南汀河下游坝区土地利用类型以园地为主,耕地次之,未利用土地、水域和建设用地所占比例均较小;近年来研究区土地利用变化有所加剧,1988～1996年、1996～2002年和2002～2009年3个时期综合土地利用动态度分别为1.83%、2.89%和3.05%,其中建设用地、未利用土地(主要为河滩裸地)、耕地的变动幅度较大;研究时段内,未利用土地面积由32.60 km2减小到9.68km2,而同期建设用地面积持续大幅增加,耕地先增后减,园地则先减后增;在距河岸1.5 km范围内,综合土地利用动态度随离河岸距离的增加而变小。

LAND USE CHANGE IN THE WIDE AND FLAT VALLY SEGMENT OF MOUNTAIN RIVER AND ITS RELATIONSHIP WITH RIVER CHANNEL -A CASE STUDY OF THE LOWER NANTING RIVER BASIN

Using ISODATA unsupervised classification and visual interpretation, four Landsat TM/ETM ＋ remote sense images acquired from 1988 to 2009 were used to analyze temporal and spatial change in land use and their relationships to the river channel dynamics in the wide and flat river valley of the lower Nanting River basin. Based on remote sensing classification results, the single dynamic degree, integrated dynamic degree, trans- fer rate of land use and other indices are calculated and then used to further analyze their relationships with the riv- er channel. The results showed that garden land and farmland were two major land use types, whereas unused land, water and building land had smaller percents. In recent years, land use change has intensified. The integrated dynamic degrees during the three periods （1988 - 1996, 1996 - 2002 and 2002 - 2009 ） are 1.83%, 2. 89%, 3.05%, respectively. In the study period, the area of unused land decreased from 32.60 km2 to 9.68 km2, while building land increased greatly. Within 1.5 km distance from the river bank, the changing rate of land uses presents a negative trend with the distance from the river bank.