面向城市规划的热环境与风环境评估研究与应用——以济南中心城为例

Research and Application of Heat and Ventilation Environment Assessment for City Planning——A Case Study of Jinan Central Urban Area

在城市尺度规划中如何定量评估规划方案对热环境与通风环境的影响是一个技术难题。基于遥感和GIS技术,建立了一套面向城市规划的热环境与通风环境评估指标和技术方法,其中热环境可采用遥感估算的地表热岛强度(SUHI)、热岛比例指数(UHPI)以及生态冷源等级进行评估;通风环境评估则包括背景风环境和地表通风潜力两方面,前者可通过气象观测统计或数值模拟得到,后者可根据下垫面动力粗糙度长度(RL)和天空开阔度(SVF)进行估算。基于城市形态学模型,RL可以由建筑密度和建筑高度进行估算,SVF可由高分辨率数字建筑高程模型进行估算。在此基础上进行通风潜力等级划分,并采用通风潜力指数(VPI)定量评估一个地区的总体通风状况。应用上述指标和方法,利用2015年济南6月12日Landsat 8卫星资料、2013年1∶2 000基础地理信息资料和2020年城市规划资料,对济南中心城区规划前后热环境与风环境进行了定量评估,并基于生态冷源、热岛强度、地表通风潜力和背景风初步开展了济南中心城通风廊道规划应用,同时给出了相关规划策略和建议。研究结果显示:(1)文章建立的热环境与风环境评估指标和技术方法可有效应用于城市规划前后变化评估中;(2)热岛强度、地表通风潜力的高低与城市分区功能定位和土地利用类型有直接关系,规划后(2020年)热岛比例指数(UHPI)从0.31增加到0.38(均为"较轻"等级),通风潜力指数(VPI)从0.89("好"等级)降至0.74("较好"等级);(3)初步构建的3条一级廊道和10条二级廊道规划方案,将有利于缓解济南中心城区热岛效应和增强城市空气流动性。

This article proposes a method of heat and ventilation environment assessment for city planning based on remote sensingand GIS technology owing to the difficulty in quantitatively evaluating the influence of city planning scheme on heat and ventilationenvironment. The heat environment can be evaluated by the indexes such as surface heat island intensity （SUHI）, heat islandproportion index （UHPI） and ecological cold source grades. The ventilation environment of a city is dependent on the backgroundwind environment and ventilation potential. The background wind environment can be assessed through meteorological statisticalanalyses or numerical simulations, whereas the ventilation potential can be estimated using the underlying surface dynamicroughness length （RL） and the surrounding sky view factor （SVF）. Based on the principle of morphology, the RL an urban area ismainly defined by the building area coverage and building height. The SVF can be estimated according to high-resolution digitalraster elevation data. Based on the combination of the RL and SVF, the ventilation potential is graded and the ventilation potentialindex （VPI） is defined and used to quantitatively assess the ventilation capacity. Using these methods and Landsat8 satellite datafrom June 12, 2015, Jinan basic geographical data at 1∶2 000 from 2013, and city planning data from 2020, this paper quantitativelyevaluates the heat and ventilation conditions before and after the construction of Jinan central city. And the assessment result isapplied in the ventilated corridors planning. According to changes in the heat island and ventilation capacity, relevant policysuggestions for urban buildings and design factors for ventilated corridors are postulated. The results show that the method is able toevaluate effectively the change of heat and wind environment before and after city planning. The heat island intensity and ventilationpotential capacity are largely depended on the functional localization of different urban zones and land utilization types. Theindustrial land for main urban area has the largest SUHI with 7.2 ℃, followed by the commercial land for main urban area with6.1 ℃ and the industrial land for eastern urban area with 5.2 ℃. The heat island intensity increases slightly and the ventilationpotential decreases after city planning. The UHPI increases from 0.31 to 0.38 and the assessment grades all are level 2 （normal） from2015 to 2020. The VPI decreases from 0.89 to 0.74 and the assessment grades are level 5 （good） and level 4 （relatively good） from2013 to 2020, separately, which can meet well the future development. The preliminary ventilated corridors planning scheme with 3first-class ventilated corridors and 10 second-class ventilated corridors for Jinan central city are constructed based on evaluation ofecological cold source grades, SUHI, surface ventilation potential and background wind field, which can effectively mitigate the heatisland effect and add the air circulation.