【摘要】 建设用地扩张是城市土地利用变化中最剧烈、最直观的表现。探究其时空演变特征及其驱动力将有助于揭示城市空间扩张机理,促进城市用地调控的科学化。以快速城市化的中型城市——扬州市为例,基于多期Landsat遥感影像(1995、2000、2005、2010和2015年)、社会经济数据等资料,分析建设用地扩张的时空演变特征,进而利用增强回归树(boosted regression tree)方法,探讨城市化进程中地理空间、社会和经济因子对建设用地扩张的影响。研究发现,1995—2015年,建设用地面积从725.4 km~2持续增加到1076.5 km~2。随着城市化的推进,建设用地的空间形态趋于紧凑、形状变得规则,重心也随之转移,表现出市辖区的局部吸引和联动特征。在地理空间、社会和经济因子中,地理空间因子(如海拔、距县市核心区和建成区的距离)对建设用地扩张的影响最大,但其相对影响却从1995—2000年的73.9%逐渐下降到2010—2015年的60.2%;社会和经济因子的相对影响则呈增加的趋势,即1995—2000年的5.2%和20.9%分别增加到2010—2015年的7.9%和31.9%。地理空间因子(如距县市核心区和建成区的距离)对建设用地扩张的影响以抑制作用为主,但不同社会经济因子的作用呈现较大差异,例如,人口密度、人均GDP和财政收入能够促进建设用地的形成,人口数量表现为抑制作用,第二产业则为先抑制后促进的作用。更多还原

【Abstract】 Built-up land sprawl is the most drastic and visual manifestation of urban land-use change. Understanding spatiotemporal change of built-up land sprawl and its driving forces can reveal the inherent laws of urban sprawl,and thus scientifically regulate urban land use. In this study,we used multi-source data( e.g.,30 m resolution Landsat images in 1995,2000,2005,2010,and 2015) and socioeconomic data to analyze spatiotemporal changes of built-up land sprawl in Yangzhou City. Further,we employed the boosted regression tree method to quantify the effects of geographic,social and economic factors on such sprawl. Results showed that the builtup land area gradually increased from 725.4 km~2 in 1995 to 1076.5 km~2 in 2015. With the increasing urbanization,the spatial form of built-up land tended to be compact and regular,and the gravity coordinates also migrated accordingly,showing local attraction and linkage of municipal districts( e.g.,Hanjiang and Guangling). Among geographic,social,and economic factors,geographic factors( e. g.,altitude,the distance from the county core,the distance from built-up land) had the greatest influence on built-up land sprawl,with the relative influence gradually decreasing from 73.9% in 1995-2000 to 60.2% in 2010-2015. The influence of social and economic factors gradually increased from 5.2% and 20.9% in 1995-2000 to 7.9% and 31.9% in2010-2015. Geographic factors( e. g.,the distance from the county core and the distance from built-up land) generally had negative effect on built-up land sprawl,but the effects of social and economic factors were inconsistent. For example,population density,GDP per capita and fiscal revenue promoted built-up land sprawl,gross population inhibited it,and secondary industry first inhibited built-up land sprawl and then promoted it.更多还原