南京江北新区城市规划对区域热环境影响的WRF模拟研究

区域热环境问题是影响城市生态环境的重要因素之一,如何通过合理的城市规划从而最大限度降低热环境问题带来的负面影响,是城市规划需要解决的关键问题之一。以南京江北新区为研究对象,基于城市规划下垫面类型数据,利用WRF模式(Weather Research and Forecasting model,WRF)来模拟近地表气温变化,进而分析研究区域热环境对城市规划的响应。研究表明:(1)高时空分辨率土地利用数据的输入能够显著提高WRF模式模拟的近地表气温精度,在此基础上耦合城市冠层模式,可以更准确地反映城市内部气温变化情况;(2)区域热环境受城市规划中土地利用类型变化的影响显著,城镇用地增加区域的气温变化幅度在不同时段有差异,其中气温升高幅度最大为1. 8℃,出现在20∶00～22∶00时段;相比于自然地表,城镇用地呈现出升温快和降温慢的特点;(3)与2013年相比,2030年研究区热岛范围扩大,热岛强度增强。因此,初步建议在城市规划时,除有效控制城镇用地增长外,需考虑该用地的分散布局,将其对热环境造成的影响降到最低,更有利于江北新区生态规划建设。

Study on the Effect of Urban Planning on Urban Thermal Environment in the Jiangbei New Area of Nanjing City Based on WRF Model

Thermal environment is one of the important factors affecting urban ecological environment. How to minimize the negative impact of thermal environmental problems through rational urban planning is one of the key issues to be solved in urban planning. Based on the change of land use in urban planning, this study used WRF model (Weather Research and Forecasting model, WRF) to simulate near-surface air temperature of Jiangbei New Area in Nanjing city, thereby analyzed the response of the thermal environment to urban planning. The obtaining results were as follows: (1) The use of land use data with high spatiotemporal resolution could significantly improve the accuracy of near-surface air temperature simulated by WRF model. On this basis, the coupled urban canopy model could simulate the near-surface air temperature change more accurately. (2) Thermal environment was significantly affected by the land use change in urban planning. The magnitude of temperature change in the urban land expansion varied over different periods of time, with the maximum increase amplitude of 1.8℃ in the period of 20∶00-22∶00. Compared with natural surface, the urban land was characterized by rapid-warming and slow-cooling. (3) Compared with 2013, the urban heat island in the study region expanded and the urban heat island intensity increased in 2030. Therefore, it is suggested that in addition to controlling the growth of urban land effectively, it is necessary to consider the decentralized layout of urban land in urban planning. It is more beneficial to minimize its impact on thermal environment, which is more conductive to the ecological planning and construction of Jiangbei New area.