重庆市2000~2015年土地利用变化时空特征分析

研究区域土地利用变化及其时空特征，可以为将来的区域土地利用规划和管理提供基础。基于2000年、2005年、2010年和2015年4期土地利用遥感影像解译数据，结合GIS空间分析方法，从土地利用变化速度、转移方向、利用程度3个方面定量分析了重庆市2000~2015年土地利用变化的时空特征。结果表明：（1）研究期内，耕地、草地和未利用土地持续减少，且耕地减少速度呈增大趋势，主要减少区域分布在主城及周边区县；林地、水域和城乡建设用地面积增加。（2）区县之间各类土地利用变化的相对速率差异较大，其中草地的相对变化率相差最大，其次为水域、耕地和林地。耕地变化最大的区域主要集中在主城区，城乡建设用地在各区县均有较大变化；水域发生较大变化的区县均与大型水利工程的修建有关。（3）重庆市在2000~2005年土地利用变化最剧烈，随后朝着越来越稳定的方向发展；区县间土地利用变化剧烈程度差异明显，但这种差异朝着缩小的方向发展。（4）渝东北、东南区域耕地、林地、草地之间转换活跃，但活跃度随时间后移递减；耕地一直是其他地类最主要的转入来源之一，城乡建设用地越来越成为其他地类的主要转出方向。（5）重庆市土地利用水平总体上处于发展期，土地利用程度的区域分布格局基本上保持不变，但差异明显，越往东北、东南区域，土地利用程度越低；全市土地利用程度变化量的分布格局呈现为以渝中区为核心从内到外依次为“弱变化——剧烈变化——较强变化——较弱变化”的圈层扩展形态。

Spatio-temporal Characteristics of Land Use Changes in Chongqing during 2000-2015

It is important for regional land use planning and management to study the characteristics of land use change. Based on GIS spatial analysis techniques and land-use data of Chongqing in 2000, 2005, 2010 and 2015 which were interpreted by remote sensing images, this study analyzed the spatio-temporal characteristics of land use changes in Chongqing during 2000-2015 from three sides including the rate of land use change, the direction of land use transformation and the degree of land use. The results showed as follows: (1) Cultivated land, grassland and unused land decreased continuously while forest land, water area and construction land increased in Chongqing from 2000 to 2015.（2) The relative change rate of each land use type in different districts and counties was quite different, and the relative change rate of grassland is the biggest, followed by water, farmland and woodland. Districts with the most obvious change of cultivated land were concentrated in the main urban area of Chongqing city while construction land had a great change almost in all districts and counties. Great changes in water area are related to the construction of large-scale water conservancy projects. (3) The most dramatic change of land use occurred during 2000-2005 and then the intensity of change gradually weakened. There was significant differences in the intensity of land use change among different districts and counties, but this difference was developing in the direction of narrowing. （4) The conversion among cultivated land, woodland and grassland in the northeast and southeast Chongqing was frequent, but the frequency reduced with time. Arable land was one of the most important sources of other types of land use all the time while construction land became the main exit of other types of land gradually. (5) The degree of land use in Chongqing was generally in the period of development. The regional distribution pattern of the degree of land use remained almost the same from 2000 to 2015 while the regional difference of land use degree was obvious—the degree of land use was becoming more and more low in the direction of southeast and northeast. The distribution pattern of the variation of land use degree in Chongqing could be characterized as loop expansion: the “Yuzhong District” as the core, from inside to outside was “weak change, intense change, strong change, weak change” in order.