雄安新区城市热岛效应的空间异质性

Spatial variation of urban heat island effect in Xiong'an New Area

以雄安新区雄县、容城县、安新县2019年9月Landsat-8卫星遥感影像为依据,采用监督分类法将土地利用类型分为5种,分析雄安新区土地利用结构特征;利用辐射传输法反演地表温度,依据均值-标准差法对地表温度进行分级,分析雄安新区地表温度空间变化及热岛强度分级情况;通过信息点(point of information,POI)对城市进行功能分区,分析高温分布影响因素。结果表明:雄安新区5种土地利用类型中耕地和建筑用地面积较大,占比分别达56.19%和31.81%,5种土地利用类型面积占比在三县的分布差异较大。雄安新区地表温度的分布特征总体是北部温度较高,南部温度较低,温度极差约为21℃,且容城县地表温度变异较大。三县的热岛强度等级面积差异较大,中温区面积最大,低温区面积最小,热岛强度等级面积占比较高的城市,其建筑用地面积占比也会较高。热岛强度的不同温区地表温度平均值与POI数量具有显著的线性正相关;不同城市功能区对地表温度具有不同影响,人类活动大的功能区地表温度高,且高温区分布在建筑用地周围,低温区分布在水域周围,中温区分布在耕地和林地。

Based on the Landsat-8 satellite remote sensing images of Xiong'an New Area,including Xiong County,Rongcheng County and Anxin County,in September 2019,the land use types were divided into five types by the supervised classification method and the land use structure characteristics of Xiong'an New Area were analyzed.The radiative transfer method was used to perform land surface temperature inversion,the surface temperature was classified according to the mean standard deviation method,and the spatial change of surface temperature and the classification of heat island intensity in Xiong'an New Area were analyzed.The point of information(POI)data were used to divide the city into functional areas and analyze the influencing factors of high temperature distribution.The results showed that among the five types of land use in Xiong'an New Area,the area of cultivated land and construction land was relatively large,accounting for 56.19%and 31.81%,respectively.The distribution of the area proportion of the five types of land use in the three counties was quite different.The overall distribution characteristics of land surface temperature in Xiong'an New Area was higher in the north and lower in the south,the range of temperature was about 21℃,and the variation of surface temperature in Rongcheng County was large.The area of heat island intensity grade in the three counties was different,with the largest area in medium temperature area and the smallest in low temperature area.Those that had higher proportion of heat island intensity grade area had the higher proportion of building area.The average surface temperature in different temperature areas of heat island intensity had a significant linear positive correlation with the number of POI.Different urban functional areas had different effects on surface temperature,the surface temperature of functional areas with large human activities was high,with the area of higher temperature being around the construction land,the area with lower temperature around water body,and the area with normal temperature being cultivated land and forest land.