西北典型山地城市绿色空间时空演化特征——以兰州市为例

Spatial-temporal evolution characteristics of urban green space in typical mountainous cities of Northwest China: A case study in Lanzhou

城市绿色空间对实现城市可持续发展至关重要,然而当前研究对西北干旱地区城市绿色空间的时空演化特征关注相对较少。因此,文中基于归一化植被指数、土地利用转移矩阵以及景观指数等方法,以西北典型山地城市兰州为例,重点刻画了2000-2020年兰州中心城区和兰州新区的绿色空间时空演化特征。结果表明:1)2000-2020年研究区内建成区扩张迅速,边缘扩张明显。兰州中心城区和兰州新区绿色空间均呈现先减后增的“V”型总体变化趋势:2000-2010年绿色空间率分别下降20.6%和0.13%,2010-2020年绿色空间率分别增加31.51%和27.8%。2)城市建设模式和政策差异导致2000-2020年兰州新区绿色空间变化强度(1.65)显著高于中心城区(1.16),二者绿色空间变化特征差异明显。3)2000-2020年研究区内绿色空间破碎化现象显著且普遍,并呈现出两种不同的演化模式。

Urban green space is crucial for achieving sustainable urban development.However,current studies rarely focus on the spatial and temporal evolution characteristics of urban green space in the northwest arid region.taking Lanzhou,a typical mountainous city in Northwest China,as an example,based on the normalized vegetation index,land use transfer matrix and landscape index,the spatial-temporal evolution characteristics of green space in Lanzhou central city and new district from 2000 to 2020 were carved.The results show that:1)The built-up areas in the study area expanded rapidly and the edges expanded significantly from 2000 to 2020.The green space in the central urban area of Lanzhou and new district in Lanzhou both showed a"V"-shaped trend of decreasing and then increasing,the green space rate decreased by 20.6%and 0.13%from 2000 to 2010,and increased by 31%from 2010 to 2020,respectively.From 2000 to 2010,the green space rate decreases by 20.6%and 0.13%,and from 2010 to 2020,the green space rate increased by 31.51%and 27.8%,respectively.2)Differences in urban construction models and policies led to the significantly higher intensity of green space change in new district of Lanzhou(1.65),which is significantly higher than that in the central city(1.16)from 2000 to 2020,and the difference in green space change characteristics between the two region is obvious.3)The fragmentation of green space in the study area from 2000 to 2020 was significant and widespread,and showed two different evolutionary patterns.