State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; Beijing Key Laboratory of Environmental Remote Sensing and Digital Cities, Beijing Normal University, Beijing 100875, China.
State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; Beijing Key Laboratory of Environmental Remote Sensing and Digital Cities, Beijing Normal University, Beijing 100875, China.
Sci Total Environ. 2020 Jul 20;727:138750. doi: 10.1016/j.scitotenv.2020.138750. Epub 2020 Apr 17.
Water body, as water cool islands (WCIs), is an effective factor of mitigating the urban heat island (UHI) effects through the evaporation and absorption of solar shortwave radiance. In this study, a combination of the range, amplitude, efficiency and capacity of the WCI effect (WCI_R, WCI_A, WCI_E and WCI_C as descriptors) within water buffers, is proposed to evaluate the interannual variation of the seasonal WCI effects within the fifth loop of Beijing from 2000 to 2018, further construct optimal regression models by seven impact factors with the four WCI descriptors through all-subset regression, as well as calculate the independent contribution rate (CR) of these factors by hierarchical partitioning (HP) analysis. The results indicate that (1) In terms of the interannual variation of WCI effects, the most significant trends that rise over fall produced by four descriptors generate in summer after 2009, while relatively stable states exist in spring and winter. (2) As for the impact factors, the water temperature (WT) and the percentage of vegetation (PV) contribute most for WCI_R, WCI_A and WCI_E in reaction to the interannual average, while the water temperature capacity (WTC) maintains significant impact on WCI_C from spring to autumn over 18 years but shares power with water temperature (WA) and WT in winter. (3) Considering the factor changes yearly, the dominance relationships of external ones, mainly the percentage of impervious surface (PI) and PV, gradually surpass that of WA and WTC in four seasons especially after 2009. On this basis, urban designers could propose suitable plans to better exert the cooling effect of water bodies, thereby reducing the UHI effect.
水体作为水体冷却岛 (WCIs)，通过对太阳短波辐射的蒸发和吸收，是缓解城市热岛 (UHI) 效应的有效因素。本研究提出了一种组合方法，即利用水缓冲区中的 WCIs 效应范围 (WCI_R)、幅度 (WCI_A)、效率 (WCI_E) 和容量 (WCI_C) 作为描述符，来评估 2000 年至 2018 年北京五环内季节性 WCIs 效应的年际变化，进一步通过全子集回归，用七个影响因素与四个 WCIs 描述符构建最优回归模型，并通过层次分区 (HP) 分析计算这些因素的独立贡献率 (CR)。结果表明：(1) 就 WCIs 效应的年际变化而言，四个描述符产生的上升趋势大于下降趋势在 2009 年后夏季最为显著，而春季和冬季则存在相对稳定的状态。(2) 就影响因素而言，在年际平均值方面，水温 (WT) 和植被百分比 (PV) 对 WCI_R、WCI_A 和 WCI_E 的贡献最大，而在 18 年的春、秋两季，WTC 对 WCI_C 保持显著影响，但在冬季与水温 (WA) 和 WT 共同作用。(3) 考虑到各年因子的变化，外部因子（主要是不透水面百分比 (PI) 和 PV）的主导关系逐渐超过 WA 和 WTC 在四季中的主导关系，特别是在 2009 年之后。在此基础上，城市设计师可以提出适当的计划，更好地发挥水体的冷却效果，从而减少 UHI 效应。
