山地新城市化进程的热岛效应时空演变特性研究

Spatio-temporal characteristics of heat island effect during new urbanization in mountainous areas

为探求山地新开发区城市化进程中的热岛效应及其热景观指数时空演变规律,以重庆市悦来新城为研究对象,利用Landsat卫星遥感影像,反演了研究区2013—2020年3个时期的地表温度,利用景观生态学的方法分析了局地和周边的热岛效应,并探讨了其与蒸散发的关系。结果表明:1)悦来新城在2013—2020年热环境空间格局发生显著变化,高温区集中在中部会展城,区域之间的温差呈逐渐缩小趋势。2)2013年悦来新城及其周边区域热岛效应弱热岛效应不明显,无极强等级区域,2013—2020年有18.45%的无热岛效应等级区域转为了热岛等级区域,极强和很强热岛效应面积增加了7.67%,分布呈中部向南、北区域发展的趋势,其中会展城扩展的区域最大,热岛重心与城市建设用地重心转移方向十分接近;2013—2020年较2013—2017年热岛效应稳定区域减小了18.76%,轻微增强区域增多了13.63%。3)悦来新城热岛效应等级以4级为主,4级热岛效应斑块数最多,相对分散,形状更加多样复杂,混合分布指数最大;5、6级热岛效应斑块数相对较少且集中。4)蒸散发主要呈减小趋势,以显著减少为主;无城市热岛效应和强热岛效应区域蒸散发差异明显,在蒸散发显著减少时,城市热岛效应呈轻微增强趋势。5)在影响研究区热岛效应的几个重要内外因中,其相关关系依次为:居民建筑物面积>人口密度>建筑物高度>气象。利用景观生态学方法分析城市热环境,及其与蒸散发的关系可为有效缓解城市热岛效应提供依据。

In order to investigate the spatial and temporal evolution of heat island effect and thermal landscape index in the urbanization process of new development zones in mountainous areas,the land surface temperature of Yuelai New City in Chongqing from 2013 to 2020 was inverted by using Landsat satellite remote sensing images.The local and surrounding heat island effect was analyzed by landscape ecology method,and the relationship between heat island effect and evapotranspiration was discussed.The results showed that:1)The spatial pattern of thermal environment in Yuelai New City changed significantly from 2013 to 2023,and the high temperature area was concentrated in the central Exhibition City,and the temperature difference between regions showed a decreasing trend.2)In 2013,Yuelai New City and its surrounding areas had weak heat island effect,no obvious heat island effect and no extremely strong grade area.From 2013 to 2020,about 18.45%of the areas without heat island effect level turned into heat island level areas,the areas of extremely strong and extremely strong heat island effect increased by 7.67%.Its distribution showed a trend of developing from the middle to the south and north,among which the expansion area of Convention and Exhibition City was the largest.The center of gravity of heat island was very close to the center of gravity of urban construction land.Compared with the period 2013-2017,the stable area of heat island effect the period 2013-2020 decreased by 18.76%,and the slightly enhanced area increased by 13.63%.3)The grade of Yuelai urban heat island effect was mainly 4,and the number of heat island effect patches in grade 4 was the largest,the patches were relatively dispersed,the shapes were more diverse and complex,and the mixed distribution index was the largest.The number of heat island effect plaques in grade 5 and 6 was relatively small and concentrated.4)The evapotranspiration decreased,mainly significantly decreased;The difference of evapotranspiration between regions with no urban heat island effect and strong heat island effect was obvious.When evapotranspiration decreased significantly,the urban heat island effect increased slightly.5)Among several important internal and external factors affecting the heat island effect,the correlation level from high to low was as follows:residential building area>population density>building height>atmosphere.In conclusion,the application of landscape ecology method to analyze urban thermal environment and its relationship with evapotranspiration could provide the basis for effectively alleviating urban heat island effect.