摘要:
深入分析城市扩张的热岛效应对解决城市热环境问题具有重要意义。以南京市为研究区,基于2000年、2010年和2020年Landsat遥感影像,应用辐射传输方程反演南京市地表温度、生物量组分指数(biophysical composition index,BCI)提取不透水面信息,运用标准差椭圆和景观指数法分析2000—2020年间南京市城市扩张的方向和类型,并基于统计学分析方法探究城市扩张类型对热环境的影响。结果表明: ①研究期内南京市地表温度从29 ℃增加至30 ℃,热岛面积由2 248 km2增加到3 051 km2,2000—2010年间城市热岛向南扩张,2010—2020年向四周扩张; ②南京市城市用地以向南为主从中心向外扩张,其中边缘式扩张类型占比最大,填充式次之,飞地式占比最小,2000—2010年间边缘式扩张模式略高于2010—2020年; ③城市扩张与城市热岛扩张方向一致,边缘式的热效应最强,其次为飞地式,填充式最小。本研究可为南京市从城市扩张类型和方向优化热环境研究提供科学依据。
Abstract:
Delving into the urban heat island effects caused by urban expansion holds crucial significance for addressing urban thermal environment challenges. Based on the Landsat remote sensing images of Nanjing in 2000, 2010, and 2020, this study obtained Nanjing’s surface temperatures through inversion using the radiative transfer equation and extracted the impervious surface information using the biophysical composition index (BCI). It analyzed the urban expansion directions and types of Nanjing from 2000 to 2020 by employing the standard deviation ellipse and the landscape expansion index. Moreover, it investigated the effects of urban expansion types on the thermal environment through statistical analysis. The results are as follows: ① From 2000 to 2020, Nanjing experienced an increase in surface temperatures from 29 ℃ to 30 ℃ and an expansion of the heat island area from 2 248 km2 to 3 051 km2. The urban heat island expanded towards the south between 2000 and 2010 and spread to the surrounding areas between 2010 and 2020; ② The urban land of Nanjing expanded outwards from its center, mainly towards the south. The expansion types were dominated by edge expansion, succeeded by infilling and exclave expansions. The proportion of edge expansion between 2000 and 2010 was slightly higher than that between 2010 and 2020; ③ The urban expansion exhibited the same direction as the urban heat island expansion, and edge expansion resulted in the most intense urban heat island effects, followed by exclave and infilling expansions. This study can provide a scientific basis for ameliorating Nanjing’s thermal environment based on the urban expansion types and directions.
下载: