Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan, 430074, China.
Remote Sensing Centre of Hunan Province, Changsha, 410007, China.
Environ Sci Pollut Res Int. 2019 Oct;26(30):30808-30825. doi: 10.1007/s11356-019-06273-w. Epub 2019 Aug 23.
Rapid urbanization significantly changes vegetation coverage and heat distribution, which threatens the sustainable development and the quality of life. As the largest developing city in Central China, Wuhan was chosen as the experimental region. This study investigated the urbanization process of Wuhan from 1989 to 2917 based on Landsat data. Combined with MODIS EVI (Enhanced Vegetation Index) and LST (Land Surface Temperature) data, vegetation disturbance and surface urban heat island (SUHI) caused by urbanization were discussed for 2001-2017. Furthermore, correlation between ∆EVI (urban EVI minus rural EVI) and ∆LST (urban LST minus rural LST) was also conducted. The results were as follows: (1) Wuhan experienced a strong urbanization over the past 29 years, with an increasing urban expansion rate and the altered dominant urban expansion pattern (edge expansion and infilling). After the enhanced vegetation functions and urban increased structures, the urbanization finally caused the fragmented patches and irregular urban shapes. (2) Urbanization had a positive effect on LST but a negative effect on EVI. From 2001 to 2017, the highest increasing rate of ∆LST for the old urban area (OUA) and urbanized area (UA) was both observed in summer daytime (OUA, 0.106 °C/a; UA, 0.207 °C/a). The decreasing rate of ∆EVI reached the highest value in summer (OUA, 0.00697/a; UA, 0.00298/a). (3) There was a strong negative correlation (except spring and winter for OUA) between ∆EVI and ∆LST in daytime, which proved that the activity of vegetation in daytime could relieve LST to a certain extent. This study clarifies the dynamic urbanization process of Wuhan and discusses its impacts on vegetation change and SUHI. Efficiently investigating urbanization process and quantifying its impacts on urban environment are critical for regional ecological conservation.
快速的城市化进程显著改变了植被覆盖和热量分布，这对可持续发展和生活质量构成了威胁。作为华中地区最大的发展中城市，武汉被选为实验区。本研究基于 Landsat 数据，对 1989 年至 2017 年武汉的城市化进程进行了研究。结合 MODIS EVI（增强型植被指数）和 LST（地表温度）数据，讨论了 2001 年至 2017 年城市化引起的植被干扰和城市热岛效应（SUHI）。此外，还进行了城市 EVI（urban EVI）与农村 EVI（rural EVI）之间的差值（∆EVI）与城市 LST（urban LST）与农村 LST（rural LST）之间的差值（∆LST）之间的相关性。结果如下：（1）在过去的 29 年里，武汉经历了强烈的城市化进程，城市扩张率不断增加，主导的城市扩张模式发生了变化（边缘扩张和填充）。经过增强的植被功能和城市增加的结构后，城市化最终导致了破碎的斑块和不规则的城市形状。（2）城市化对 LST 有正效应，但对 EVI 有负效应。从 2001 年到 2017 年，老城区（OUA）和城市建成区（UA）的 ∆LST 增长率最高的均为夏季白天（OUA，0.106°C/a；UA，0.207°C/a）。夏季 ∆EVI 的下降率达到最高值（OUA，0.00697/a；UA，0.00298/a）。（3）在白天，∆EVI 与 ∆LST 之间存在很强的负相关关系（OUA 的春季和冬季除外），这证明了植被在白天的活动可以在一定程度上缓解 LST。本研究阐明了武汉的动态城市化进程，并讨论了其对植被变化和城市热岛效应的影响。有效调查城市化进程并量化其对城市环境的影响对于区域生态保护至关重要。
