基于地表参数变化的南京市热岛效应时空演变特征分析

Spatio-temporal Evolution Characteristics of Nanjing Heat Island Effect Based on Variation of Surface Parameters

针对城市热岛效应引发的一系列生态安全、居民健康等问题,选择传统“火炉城市”南京市为研究区,利用Landsat影像反演地表温度(land surface temperature,LST),进而获得研究区热岛空间分布,分析热岛重心转移情况,最后以空间叠加、回归统计分析方法分析建筑、植被、水体对于LST的影响程度。结果表明:2000—2020年南京市热岛、强热岛斑块随着建成区的扩张而扩张,面积占比由6.48%上升到40.81%,而绿岛、强绿岛区则由37.38%下降到13.39%,地表温度呈现明显城乡梯度差;热岛、强热岛斑块重心转移方向与城镇重心转移方向一致,都呈“先南后西”方向偏移,绿岛、强绿岛转移方向则相反;下垫面覆盖对地表温度的影响分别是建筑>植被>水体。该研究成果可为南京市城市规划以及热岛效应缓解提供一定依据。

Aiming at a series of ecological security,residents’health and other problems caused by urban heat island effect,Nanjing,a traditional“stove city”,is selected as the research area,and the Landsat image is used to retrieve the land surface temperature(LST).It obtains the spatial distribution of heat island in the research area,analyzes the transfer of heat island center of gravity,and finally analyzes the influence degree of buildings,vegetation and water bodies on LST by spatial superposition and regression statistical analysis.The results show that:from 2000 to 2020,Nanjing heat island and strong heat island patches expanded with the expansion of built-up areas,the area proportion increased from 6.48%to 40.81%,while green island and strong green island areas decreased from 37.38%to 13.39%,and surface temperature showed obvious gradient difference between urban and rural areas;the transfer direction of the center of gravity of heat island and strong heat island patches is the same as that of cities and towns,both of which are offset in the direction of“first south and then west”,while the transfer direction of green island and strong green island is opposite;the influence of underlying surface coverage on surface temperature is architecture>vegetation>water body.The research results can provide a certain basis for urban planning and mitigation of heat island effect in Nanjing.