渭干河-库车河三角洲绿洲土地利用/覆被时空变化遥感研究

土地利用/覆被变化(LUCC)是全球变化研究的重要核心问题之一,选择干旱区典型绿洲新疆渭干河—库车河三角洲绿洲为研究靶区,利用1989年、2001年、2006年和2010年的同期遥感影像数据,借助RS和GIS技术,对绿洲土地覆盖变化信息进行定量提取和分析。结果表明:①1989—2001年,各类地物面积呈现五增二减的趋势:耕地、林地、中度盐渍地、水体和其他均有所增加;而轻度盐渍地和重度盐渍地有所减少;2001—2006年,呈现四增三减的趋势:耕地,轻度盐渍地,中度盐渍地和重度盐渍地均有所增加;林地、水体和其他均有所减少;2006—2010年,呈现四增三减的趋势:中度盐渍地,重度盐渍地、水体和其他均有所增加;耕地、林地、轻度盐渍地均有所减少。②随着时间的推移,各类地物的重心均有所偏移。其中水体的重心于1989—2001年间向北迁移的距离最远,为23.12 km;同期重度盐渍地重心迁移距离次之,为22.04 km。林地的重心于1989—2001年间逐年向西南方向迁移,并且迁移的距离逐年增大,中度盐渍地重心总体向西北方向偏移。③21年间,Shannon多样性指数、Shannon均匀度指数均呈稳步增加的趋势,景观的异质性程度呈现上升趋势;聚集度差异不大,集中在78到85之间,说明斑块类型连接程度较高。1989—2006年,分维数增加,研究区的土地利用景观格局愈来愈复杂,人类干扰程度在不断增强;2006—2010年,分维数略有所下降,景观格局略有所改善。总之,21年间渭-库地区各类型土地利用情况变化显著,不仅各土地覆盖类型间面积转换频繁,而且土地利用景观格局发生了很大的变化。该研究确定了土地利用/土地覆被的时空变化规律,分析驱动因子,提出改良建议,研究结果对西部干旱区绿洲的环境演变和可持续发展研究具有现实意义,也是对全球变化研究的重要补充。

Dynamics of land use/cover changes in the Weigan and Kuqa rivers delta oasis based on Remote Sensing

Land use/1and cover change(LUCC)is one of the core issues in global change research. This study takes the typical oasis of Weigan and Kuqa rivers, which are located in the north of the Tarim Basin, using 4 temporal images combined with field survey. With the application of Remote Sensing and Geographic Information Systems, classified statistic and LUCC transform matrix were acquired. The conclusions are as follows: (1)In the period from 1989 to 2001,the areas of farmland,woodland, moderate saline land, water and the other (Gobi, sand and clay, etc.) have increased; slight saline land and heavy saline land has reduced. In the period from 2001 to 2006, the areas of slight saline land, moderate saline land and heavy saline land have increased; the other types of land use/covers have reduced. In the period from 2006 to 2010, the areas of moderate saline land, heavy saline land, water and the other have increased; the other types of land use/covers have reduced. (2)As time went by, the gravity center of every type of land use/covers has changed. The farthest distance is the change of gravity center of water between 1989 and 2001, which is 23.12km. At the same period, The distance of the gravity center of heavy saline land moved to the northwest is smaller than that of water, which is 22.04km. The gravity center of woodland moved to the southwest, and the transferred distances increased year by year. The gravity center of moderately and slightly saline land in essence transferred to northwest during these 21 years.(3)From 1989 to 2010, the Shannon diversity index and the Shannon evenness index are both steadily increasing, which indicates that heterogeneity is on the rise. The Aggregation Index is insignificant, with concentrations between 78 and 85, indicating that the connection is in a higher degree of the same patch types. In the period from 1989 to 2006, fractal dimension indexes have increased, with the increase of human interference degrees; land use landscape pattern has become more complex in the study area. From 2006 to 2010, fractal dimension indexes have decreased, While landscape has shown slight improvement. In short, various types of land use changes have significantly affected the study area over the past 21 years. In all, not only the transition of one type of land into another was frequent, but also the landscape pattern was subjected to many changes. This study identified the land use/cover changes of time and space, analysis the driving factors, In addition, this study makes suggestions for improvement. The results of the Western Oasis's environmental changes and sustainable development research have practical significance and is also an important complement to global change research.