6种城市下垫面热环境效应对比研究

选择6种具有代表性的城市下垫面(沥青路面、水泥路面、荷兰砖地面、草地、嵌草砖地面、大理石地面)作为观测对象,基于热红外成像技术对其地表温度特征进行观测,系统分析不同城市下垫面地表温度的日变化以及季节变化特征,并利用不同下垫面温度的时间标准差、空间标准差及时空数据标准差定量揭示城市不同下垫面地表温度的时空变化特征,对比研究不同下垫面的热环境效应,结果如下。1)不同下垫面地表温度的日变化一般呈先上升后下降的单峰形态,草地地表温度在不同季节的日变化波动差异较大。沥青的地表温度在全年均为最高,对热环境的影响较大;嵌草砖和大理石在全年的温度均较低,对热环境具有较好的缓解作用,且缓解作用在夏季最显著。2)不同下垫面地表日均温度全年均高于大气温度,表明城市下垫面对大气在一年中都有加热作用。3)气温、太阳辐射以及空气相对湿度对下垫面地表温度的影响均较为显著;气温和太阳辐射与下垫面地表温度之间呈正相关关系,对下垫面以增温作用为主;空气相对湿度与下垫面地表温度之间呈负相关关系,对下垫面增温起抑制作用。4)嵌草砖的热环境稳定性较草地和大理石要好;沥青路面的温度变化特征最能代表本研究观测区域下垫面地表温度的时空变化特征。研究结果对了解城市不同下垫面热环境具有一定参考意义,可为缓解城市热环境提供科学依据。

Comparative Study on the Thermal Environment Effect of Six Urban Underlying Surfaces

Surface temperature characteristics of six typical underlying surfaces, namely, asphalt pavement, cement pavement, grass, marble pavement, pavement bricks and grass-planting bricks, were observed with thermal infrared imaging technology. The diurnal and seasonal variations of surface temperature of different underlying surfaces were systematically analyzed. By means of the standard deviation (SD), the temporal and spatial microclimatic dynamic characteristics of different underlying surface temperature were revealed. The results are as following. 1) Diurnal variation of surface temperature of different underlying surfaces present unimodal pattern, diurnal variation of grass surface temperature changes greatly from season to season. Asphalt surface temperature is highest among the whole year, having a great effect on thermal environment while temperatures of grass-planting bricks and marble pavement are the lowest, having a relief effect on thermal environment, especially in summer. 2) The daily average temperature of different underlying surfaces are higher than air temperature, showing that underlying surface keeps heating the air throughout the year. 3) The underlying surface temperature is strongly affected by air temperature, relative humidity and solar radiation. Air temperature and solar radiation are positively related with surface temperature, showing that air temperature and solar radiation play a role in warming the land surface. On the contrary, relative humidity is negatively correlated with surface temperature, turning out that relative humidity plays a role in cooling the land surface. 4) Grass-planting bricks have a more stable thermal environment than grass and marble bricks. Temperature changing characteristic of asphalt pavement best represents the spatial and temporal variation characteristics regarding the temperature of underlying surface. The results have certain reference significance for knowing thermal environment of different urban underlying surfaces, while providing scientific evidence for alleviating urban thermal environment.