福州主城区绿色空间演化的热环境效应差异

The differences of thermal environment effect of urban green space evolution: A case study of Fuzhou

以福州主城区为研究对象,从时间和空间尺度两方面,基于Landsat遥感数据提取了土地利用类型,并在此基础上反演了地表温度,分析了城市化进程中城市绿色空间演化所引起的地表热环境效应特征。结果表明:1993—2013年,福州市的土地利用/覆盖发生显著变化,城市绿色空间(林/草地、水体和湿地)面积减少,建设用地面积大幅度增加;不同土地利用类型的地表温度具有显著差异,建设用地和裸地对研究区的地表增温有正贡献,绿色空间表现为负贡献;不同绿色空间类型的降温差异明显,表现为水体>湿地>林/草地;不同绿色空间的演化过程产生了多样化的温度效应格局,绿色空间损失区引起的温差最为显著,交换区和扩张区引起的温差略高于不变区域;通过温度植被指数的模型构建,定量评估了不同绿色空间类型的演化方向与演化效应的关系。研究结果可加深对不同绿色空间类型对城市热岛效应缓解作用的认识,为河流沿岸城市不同的绿色空间保育提供有益借鉴。

We quantified the land surface thermal environment during urbanization of the main urban area of Fuzhou by extracting the land use/land cover( LULC) based on Landsat series remote sensing data and retrieving the land surface temperature( LST). The results showed that there were dramatic changes in LULC of Fuzhou from 1993 to 2013,with the reduction of urban green space( UGS) including forest/grass,water and wetland and the significant increase of built-up land. The LST of different LULC had significant differences. The build-up land and bare land had positive contribution to the LST,while the UGS had negative effect on LST,with the order of water > wetland > forest/grass. During the evolution process of different types of UGS,there was a diversified temperature pattern. The ΔLST caused by UGS loss was the most obvious,followed by the UGS exchange and the UGS extension regions. The relationship between evolution direction of different UGS types and temperature effect was quantified by TVX. Our results might help understand the mitigation effect of different UGS types on urban heat island effect and provide useful reference to the conservation of green space in coastal cities.