The thermal environmental effects of changes in urban green space: A mesoscale modelling perspective

IF 4 2区地球科学 Q1 GEOGRAPHY

Applied Geography Pub Date : 2024-07-06 DOI:10.1016/j.apgeog.2024.103338

Xiangwen Deng , Qian Cao , Lunche Wang , Wei Wang , Haiting Li , Shuai Wang

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Abstract

Green space is an important adaptation strategy against urban thermal environmental change. However, the impact of the spatiotemporal changes in green space on urban mesoscale meteorology and human thermal comfort has been understudied. Here, we incorporated gridded urban green fraction (GF) corresponding to 2016 and 2020 in central Wuhan into the Weather Research and Forecasting model to investigate the thermal environmental effects of changes in GF. Results show that a 10% increase in GF produced a nighttime cooling of 0.167 °C and a daytime cooling of 0.075 °C. Meanwhile, it increased atmospheric moisture content by 0.131 g/kg in the daytime and 0.042 g/kg at night. Consequently, the nighttime heat index (HI) was reduced by 0.258 °C but the daytime HI was raised by 0.056 °C. Addition of GF induced a greater magnitude of change in 2-m air temperature and the HI when the GF in a grid cell exceeded 0.6. The reduction in ground heat flux due to the conversion of urban fraction to green fraction, in conjunction with the weak turbulence, contributed to the greater magnitude of cooling in the nighttime than in the daytime. To enhance green space connectivity should be an effective pathway to thermal adaptation in high-density built environments like Wuhan.

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城市绿地变化的热环境效应：中尺度建模视角

绿地是应对城市热环境变化的重要适应策略。然而，绿地时空变化对城市中尺度气象学和人类热舒适度的影响研究不足。在此，我们将武汉中心城区 2016 年和 2020 年的网格化城市绿量（GF）纳入天气研究与预报模型，研究 GF 变化的热环境效应。结果表明，GF 增加 10%，夜间降温 0.167 ℃，白天降温 0.075 ℃。同时，白天大气含水量增加了 0.131 克/千克，夜间增加了 0.042 克/千克。因此，夜间热指数（HI）降低了 0.258 °C，但白天热指数升高了 0.056 °C。当网格单元中的 GF 超过 0.6 时，加入 GF 会导致 2 米气温和 HI 发生更大的变化。城市部分转化为绿地部分导致地面热通量减少，再加上湍流较弱，导致夜间降温幅度大于白天。在武汉这样的高密度建筑环境中，加强绿地的连通性应是热适应的有效途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Geography GEOGRAPHY-

CiteScore

8.00

自引率

2.00%

发文量

134

期刊介绍： Applied Geography is a journal devoted to the publication of research which utilizes geographic approaches (human, physical, nature-society and GIScience) to resolve human problems that have a spatial dimension. These problems may be related to the assessment, management and allocation of the world physical and/or human resources. The underlying rationale of the journal is that only through a clear understanding of the relevant societal, physical, and coupled natural-humans systems can we resolve such problems. Papers are invited on any theme involving the application of geographical theory and methodology in the resolution of human problems.