马鞍山市区山森林热场效应及缓解城市热岛的作用

Thermal effect of hill forest and its function in urban heat island mitigation in Maanshan city

应用2010年7月的卫星遥感影像为数据源,运用GIS技术将该影像进行亮温反演和温度分级,以分析研究马鞍山市建成区山林对城市热岛效应的影响。结果表明,马鞍山市建成区热岛效应显著,中温区面积最大,占总面积的56.64%。城市山林均位于中温区,山林斑块的热场效应有一定的辐射范围,其降温效应与据斑块的距离呈负相关关系,其辐射范围与斑块面积、斑块的周边长、拥有的生物总量呈正相关,与斑块的形状无关,相关模型为y=﹣444.961 51-6.148 90 x1+0.058 90 x2+484.280 66 x3+0.013 81 x4,影响程度为生物量>斑块面积>斑块周长。研究区9座山林面积为5.7 km2,其热场效应的辐射距离最大达1 160 m,总面积达30.16 km2,占研究区总面积的45.0%,城市森林斑块缓解城市热岛效应的作用显著。因此,提高城市森林斑块的生物量、增加斑块面积可有效地缓解城市热岛效应。

Based on the data of Maanshan Landsat5 /TM taken in July, 2010, the heat island effect of build-up areas in Maanshan city was analyzed by mean of brightness temperature inversion using GIS technology, and urban heat island mitigation affected by urban hill forest was studied. The study area covered 67 km^2. The results showed that the heat island effect was obvious in the city, and the area classified as middle temperature accountting for that 56.64% of the total area. It was apparent that hill forest patches has obvious effects on lower- ing temperature. The thermal effects of hill forest patches covered a certain area, and had a significant negative relevance to the distance in lowering temperature. The thermal effect range of hill forest was positive related to biomass in a patch, patch area and patch perimeter, but not significantly related to patch shape, as expressed as y=-444.961 51 -6.148 90 x1 ＋ 0.058 90 x2 ＋ 484.280 66 x3 ＋ 0.013 81x4. The 9 hill forest patches only cover 5.7 km^2, but their thermal effects expanded to 30.16 km^2 which accounted for 45.0% of the studied area with the maximum radiation distance of 1 160 m. Therefore, increasing biomass of urban forest patch and patch area are effective ways to mitigate urban heat island effect.