基于空间自相关的城市热岛时空格局变化

Spatiotemporal Pattern Changes of Urban Heat Island Based on Spatial Autocorrelation

[目的]明确空间自相关分析方法运用于揭示城市热岛时空变化规律的有效性和可行性。[方法]利用Landsat热红外波段进行地表温度反演,采用空间自相关局部指标G系数进行城市热岛范围的界定,并进行1996—2016年福州城市热岛的时空格局研究。[结果]1996—2016年城市热岛范围持续扩展,热岛状况的恶化速度大于缓解速度,热岛问题日益严重,但在热岛内部,强度却有所缓解,福州热岛效应的威胁主要来源于城市扩展形成的新热岛区。[结论]空间自相关局部指标G系数能同时兼顾地表温度的高低及其空间相关关系,不仅能从统计学意义上有效地界定城市热岛范围,还能从可视化角度揭示其时空变化规律,从而为城市热岛定量研究提供新思路。

Objective] To find the effectiveness and feasibility of applying Spatial Autocorrelation Analysis Method in revealing spatiotemporal change law of urban heat island.[Method] Landsat thermal infrared band was used to define the spatial autocorrelation local index G coefficient within the range of urban heat island.Spatiotemporal pattern of urban heat island in Fuzhou was researched from 1996 to 2016.[Result] Within 1996-2016,heat island problem deteriorated,featuring continuous expansion of heat islands and higher rate of deterioration than that of mitiga-tion.But the intensity of heat was mitigated inside the heat islands.This showed that the threat of heat island in the city was mainly from the new heat island areas developed in the process of urbanization.[Conclusion] Spatial autocorrelation local index G coefficient reflects both the level of land surface temperature and its spatial correlation.It helps to define the scope of urban heat island statistically and to visualize the spatiotemporal dynamics.This research provides a new way of research on urban heat island.