A Framework for Assessment of the Influence of China’s Urban Underground Space Developments on the Urban Microclimate

The paper aims to establish the framework for linking underground space projects and the urban microclimate, in order to construct an interdisciplinary research framework. Based on the combination of underground space, urban form and the urban microclimate, the impacts of underground space on urban microclimate factors above ground and underground are summarized and the internal mechanism is investigated. The above ground factor refers to the impact of a new urban form induced by the underground space planning on the urban microclimate. The underground factor refers to the impact of the control of the internal environment of underground space on the ground environment. This study mainly addresses two aspects. Firstly, to identify the influencing factors of urban underground space microclimate and define the research entry point and classify the indicator of the external space environment; secondly, to address the key issues of the research areas and their influence on the urban underground space project and the urban microclimate in the current phase and establish the direction of future research. The microclimate case of the Nanjing underground planning is provided to preliminarily analyze how underground space development improves the urban microclimate. By the comparative analysis of microclimate parameters, air quality parameters, and outdoor thermal environment parameters (Mean Radiant Temperature, MRT), the influences and benefits of underground space projects on the urban microclimate is quantitatively explored.