摘要
热岛效应是快速城市化进程中最具代表性的生态环境问题之一。以绿地和水体为主体的城市公园所形成的"城市冷岛"是缓解城市热岛效应和改善城市热环境的有效途径。研究选取北京市城区24个公园为研究对象,利用landsat-5 TM遥感影像反演城市地表温度,探讨城市公园内部景观构成、斑块形态和空间布局这3个方面的空间结构特征与其内部温度(Ta)、对周边环境降温的影响范围(Lmax)及降温幅度(ΔTmax)的关系。研究表明:从景观构成来看,Ta、Lmax、ΔTmax与水体面积均呈现显著相关性,是影响公园内外热环境的关键因子;Ta及ΔTmax与公园内绿地面积无显著相关性,而主要受三维绿量和硬质地表比例的影响;与此相反,Lmax与绿量相关性并不显著,但与林地面积呈显著正相关。因此,综合考虑公园内外整体降温效应,应在保证绿地面积达到一定规模的同时,尽量丰富绿地内部空间结构,增大三维绿量;从斑块形态来看,绿地斑块形状越复杂,公园内部温度越低,影响范围越远,而公园外围边界形状与内部温度呈较显著正相关,但对周边热环境的影响并不明显;从空间布局来看,硬质地表分布与Ta、Lmax、ΔTmax均显著相关,其布局越分散,内部温度越低,对周边的影响范围及降温幅度越大;此外,公园林地布局越分散,内部温度越低,影响范围越大,但对ΔTmax影响不明显。在城市公园规划设计中,从缓解城市热岛效应出发,应将公园景观内部的空间结构特征作为重要的考虑因素之一。
Urban Heat Island（ UHI） is one of the major problems in the 21stcentury posing to human beings as a result of urbanization and industrialization. It is primarily triggered by the dense built environment（ i. e.,replacement of the natural landscape） as well as anthropogenic heat in cities,and has led to huge negative impacts on human life. Urban parks,which are known as ＂Urban Cool-island＂,have been considered as an effective measure in alleviating UHI effects and improving urban thermal environment. Nevertheless,as urban land use is of high tension,it has become a serious issue during the planning and designing process of city parks that how to maximize the ecological functions of the park landscape,and to make it effective in improving the urban ecology and urban climate. In this study,24 city parks in the urban area of Beijing were selected to explore the effects of spatial characteristics of city parks（ including the landscape composition,the patch morphology and the spatial distribution） on internal and external thermal environment,including the temperatureinside the parks（ Ta）,sphere of influence on the surrounding environment（ Lmax） and the maximum cooling range（ ΔTmax）. Temperature distribution was inversed from Landsat-5 TM remote sensing data. The results showed that from the perspective of the landscape composition,Ta,Lmaxand ΔTmaxwere positively correlated with water areas at a significant level,which was considered as the key factor affecting the thermal environment both inside and outside the parks. TaandΔTmaxrepresented no significant correlation with the forest and lawn areas. Comparatively,they were closely related with the greenness and the proportion of impermeable surface. Conversely,Lmaxhad no obvious correlation with the greenness,but was substantially positively correlated with the forest area. Hence,in order to maximize the cooling effects both inside and outside the parks,it would be of necessity to enrich the inner spatial structure of green space and increase the threedimensional greenness to the greatest extent under the premise of ensuring a certain size of the green space area. With respect of the patch morphology,the more complex the geometric shape of green patch was,the lower the internal temperature and the further the sphere of influence would be. The boundary shape of the park displayed a certain correlation with the internal temperature,but had no distinct impacts on the surrounding thermal environment. In terms of the spatial distribution,Ta,Lmax,and ΔTmaxwere all remarkably associated with the distribution of impermeable surface. That is,the more dispersed the impermeable surface arrangement was,the lower the internal temperature and the larger sphere of influence and cooling range would be. In addition,the parks with more dispersed forest distribution would bring about the lower internal temperature and the larger sphere of influence. While the forest distribution of the parks had no apparent impacts on ΔTmax. In conclusion, from the perspective of the urban heat island mitigation, the spatial landscape characteristics of parks should be taken as important considerations in the city park planning and design.
出处
《生态学报》
CAS
CSCD
北大核心
2014年第12期3179-3187,共9页
Acta Ecologica Sinica
基金
国家科技支撑计划(216029)
国家基金委创新研究群体科学基金(51121003)
关键词
热岛效应
城市公园
空间景观特征
影响范围
降温幅度
urban heat island
city park
spatial landscape characteristic
sphere of influence
cooling range
