热浪环境下大连城市公园景观特征对冷岛效应的影响

Influence of Landscape Characteristics on Cold Island Effect in Dalian City Park under Heat Wave

为阐述不同景观特征下城市公园冷岛效应缓解热浪和的影响机制,基于Landsat 8遥感影像反演地表温度,探究了大连24个城市公园对热浪环境的响应变化。结果表明:热浪对地表温度有显著影响;热浪环境下,公园降温范围变化(ΔC)介于-68.38~92.67 m,冷岛强度变化(ΔP)介于-1.532~0.783℃,不同公园对热浪的响应存在差异,且同一公园ΔC、ΔP的趋势并不完全一致;影响ΔC的重要景观参数依次为林地面积比、草地面积比和草地聚合度,影响ΔP的重要景观参数依次为地表面积比、水体面积比和草地面积比。应对热浪环境时,抵抗型公园(ΔC>0且ΔP>0)可以更好地缓解热浪,通常其林地面积比大于48.5%,地表面积比小于11%,水体面积比大于29%,草地面积比小于41%,草地聚合度小于97.8%。

In order to explain the influence mechanism of the cold island effect in urban parks to alleviate the heat wave under different landscape characteristics, this study explored the response changes of 24 urban parks in Dalian to heat wave environment based on land surface temperature data retrieved by Landsat 8 thermal infrared band. The result showed that heat wave had a significant impact on the land surface temperature. Under the heat wave environment, the change in cooling range(ΔC) of parks ranged from-68.38 to 92.67 m, and the change in cold island intensity(ΔP)ranged from-1.532 to 0.783°C. Different parks had different responses to heat waves. And the changing trends of ΔC and ΔP in the same park were not completely consistent. The important landscape parameters affecting ΔC were forest area ratio, grassland area ratio, and grassland aggregation degree. The important landscape parameters affecting ΔP were surface area ratio, water area ratio, and grassland area ratio. When dealing with the heat wave environment, the urban parks with the resistance type(ΔC>0 and ΔP>0) can better mitigate heat waves, and the forest area ratio was usually more than 48.5%, land surface area ratio was less than 11%, water area ratio was greater than 29%, grassland area ratio was less than 41%, and grassland aggregation degree was less than 97.8%.