基于地形梯度的哈尔滨市土地利用格局变化分析

Analysis on land use pattern changes in Harbin based on terrain gradient

为揭示土地利用格局变化在地形差异上的演变过程,探讨不同地貌部位自然因素和人文因素在土地利用变化过程中的作用,以1989年、1995年、2001年和2007年Landsat TM/ETM+影像为主要数据源,在RS和GIS支持下获取土地利用数据。基于地学信息图谱分析理论,研究该区域不同时期土地利用空间格局变化进程,揭示土地利用变化成因和机理,并基于DEM(digital elevation model)探究土地利用图谱地形梯度的空间分异和时空演变规律。结果表明:土地利用结构以耕地和林地为主,耕地和未利用地面积持续减少,平均斑块面积分别由20.96km2减少到2.87km2和3.92km2减少到0.09km2,破碎化程度加剧,且未利用地(滩涂地和湿地)→耕地是其主要的转变轨迹,居民工矿用地呈现不平衡的增加态势,耕地是居民工矿用地和林地的主要转化来源,林地的破碎度由0.117个/km2增加到0.532个/km2,破碎化程度日益严重;前期变化型和持续变化型的分布指数在地形位等级2时最大,稳定型和反复变化型的在地形位等级1时最大,之后随着地形位的增加而减小;中间过渡型呈现一定的曲线变化。该文为城市化过程中的土地资源的合理规划和利用提供科学依据。

Rapid land use pattern change has taken place in Songhua River basin of old industry base in Northeast Region of China over the past decades in Harbin Province. To explore evolution process of land use pattern on terrain gradient, data interpreted with RS and GIS technology from remote sensing images （Landsat TM/ETM＋） were collected in 1989, 1995, 2001 and 2007, respectively. Based on the geo-information image analysis theory, the rules of land use spatial pattern changes and structural characteristics were analyzed, reasons and mechanisms of land use change were disclosed. Afterwards, terrain gradient-based spatial differentiation and spatial-temporal evolution process of land usage were studied further based on DEM （digital elevation model）. The results showed during the past 18 years, cropland and forestland were the dominant land use types, areas of cropland and unused land were decreased constantly, the average area of cropland patch were decreased from 20.96 km2 to 3.92 km2,while the average area of unused land patch was decreased from 2.87 km2 to 0.09 km2, which showed that the fragmentation degree of both cropland and unused land aggravated seriously, and at the same time, the estuarine and coastal wetlands were the main transformation trace to cropland for unused land. Areas of cultivated land were increased constantly with an unbalanced station. Compared to the increased land areas of cultivated land, cropland acted as the main source for transforming to the other land use types, the fragmentation of forestland was increased from 0.117 to 0.532 piece /km2, which showed that the fragmentation degree became more and more serious. When the terrain niche grade was 2, the distribution index of the Pre-change Model and the Continuous Change Model reached their top values. However the Stable Model and the Repetitive Change Model became the largest when the terrain niche grade changed to 1. Afterwards, distribution index of these models was decreased with the increase of the terrain niche grade. Distribution of the Intermediate Transition Model matched with the certain curve. This study provides a scientific basis for planning and using land properly in the process of urbanization.