景观格局对城市热环境的影响——以南昌市为例

Influence of landscape pattern on urban thermal environment:a case from Nanchang

基于1989、2001、2011和2017年Landsat遥感影像反演地表温度和提取地表覆盖信息,利用Uniform tiles和单因素线性回归方法,研究了1989—2017年南昌市景观格局的变化对热环境的影响,分析了城市发展过程中景观格局对地表温度的影响机制及影响因素。结果表明:1)1989—2017年,不透水表面景观面积增加了195.57 km^(2),城市热岛区域面积扩大了217.74 km^(2),2017年热岛区域面积已高达432.76 km^(2)。2)热环境区域的景观类型主要为不透水表面,占比每增加10%,温度上升0.62℃;而绿地、水体景观占比每增加10%,温度则下降0.79℃。3)不透水表面景观空间分布越集中,斑块越紧凑,密度越大,将导致地表温度升高,热岛效应进一步增强;绿地、水体景观则相反。景观格局是影响城市热岛效应的决定性因素,在城市化进程中,合理规划城区景观格局将有效缓解城市热环境现象。

The impact of landscape pattern changes on thermal environment of Nanchang is examined from 1989 to 2017.The impact of landscape pattern on surface temperature is obvious during urban development.Based on Landsat images from Nanchang,land surface temperature inversion and surface coverage information extraction were performed.Uniform tiles and single-factor regression analysis method were used to analyze the spatial evolution characteristic of urban thermal environment and its influencing factors.It is found that the impervious area increased 195.57 km^(2),and the urban heat island area expanded 217.74 km^(2)from 1989 to 2017.In 2017,the urban heat island area reached 432.76 km^(2).The landscape type in the thermal environment area is mainly the impervious surface,with the temperature increase 0.62℃for every 10%in the proportion.If the proportion of green space and water landscape increased 10%,the temperature will decrease 0.79℃.The more concentrated the pattern distribution of the impervious surface is,the more compact the patch is and the greater the density is,resulting in the land surface temperature rise and further heat island effect.Green space of water landscape is opposite.Landscape pattern is the decisive factor affecting urban heat effect.In the process of urbanization,rational planning of urban landscape pattern will effectively reduce urban thermal environment phenomenon.