Impact of urban morphology on microclimate and thermal comfort in northern China Shanshan Tong a,⇑ , Nyuk Hien Wong a , Chun Liang Tan a , Steve Kardinal Jusuf b , Marcel Ignatius a , Erna Tan a a School of Design and Environment, National University of Singapore, 4 Architecture Drive, Singapore 117566, Singapore b Sustainable Infrastructure Engineering, Singapore Institute of Technology, 10 Dover Drive, Singapore 138683, Singapore article info Article history: Received 13 March 2017 Received in revised form 8 June 2017 Accepted 9 June 2017 Keywords: Urban Heat Island (UHI) Temperate climate Microclimate Greenery Outdoor thermal comfort Thermal Sensation Vote (TSV) model abstract This work is an experimental study focusing on the impact of urban morphology on the urban heat island (UHI) intensity, microclimate conditions and thermal comfort in a newly-developed urban area in Tianjin city, China. According to the Köppen–Geiger climate classification system, the studied area is classified as hot summer continental climate, characterized by hot and humid summers as well as cold and dry win- ters. Air temperature, relative humidity (RH) and wind speed at 46 points within an 8-km 2 area are mea- sured during both winter and summer seasons. Based on measured results and climatic mapping, the impacts of urban constituents such as building, pavement, greenery and water area on UHI intensity and microclimate conditions are analyzed. Results show that UHI intensity reaches up to 4.5 °C during daytime and 5.3 °C at night in summer, and 2.6 °C during daytime and 5.0 °C at night in winter. Thermal comfort level at the measurement points is predicted using the Thermal Sensation Vote (TSV) model developed for the local climate. The cooling effect of trees is evident during both daytime and nighttime in summer, but negligible in winter due to the reduction of leaf area and evaporation. The pres- ence of both greenery and water body result in an increase in RH in air. Trees tend to reduce wind speed and improve thermal comfort in winter. Radiant heat dissipated from buildings and roads is the main contributor to nighttime UHI in both summer and winter seasons. Based on research results, urban design recommendations are proposed so as to improve outdoor thermal comfort in urban areas located in tem- perate climate zone during summer and winter. Ó 2017 Elsevier Ltd. All rights reserved. 1. Introduction More than half of the world’s population became urban resi- dents in 2009 and this number is projected to reach 66% by 2050 (Valladares-Rendón and Lo, 2014). Although the urbanization pro- cess brings along rapid economic growth and industrial develop- ment, it also causes a general deterioration of urban environment. Urban Heat Island (UHI) effect is one of the environ- mental problems caused by human modification of land surfaces. UHI refers to a city or metropolitan area which is significantly war- mer than its surrounding rural areas (Oke, 1982). This problem is commonly present in cities of all climate regions. In the context of global warming, the UHI effect has garnered the attention of city planners, building engineers and government policy makers, espe- cially in the tropical or subtropical areas such as Singapore (Wong and Yu, 2009), Hong Kong (Siu and Hart, 2013) and Malaysia (Rajagopalan et al., 2014). Heat islands can be categorized into three types: canopy layer heat island, boundary layer heat island and surface heat island. The first two heat islands refer to the warming of urban atmo- sphere at different vertical scales and can be directly measured using thermometers. The surface heat island refers to the warming of urban surfaces and is often measured by remote sensors mounted on satellites or aircraft (Voogt, 2004). Air temperature in urban canopy layer plays an important role in determining out- door thermal comfort as well as space heating and cooling loads in buildings. Extensive usage of air-conditioning to achieve thermal comfort in summer can intensify the UHI effect due to emission of waste heat (Santamouris and Asimakopoulos, 2001). The increased air temperature could further exacerbates peak electric- ity demand for air-conditioning by 5–10% (Akbari et al., 2001). The UHI effect has a profoundly negative effect on outdoor thermal comfort and could increase health risks of urban residents in sum- mer (Santamouris et al., 2011). Urban air temperature is affected by climatic and urban factors such as solar radiation, wind, precipitation, Sky View Factor (SVF), building density, greenery, albedo and water area (Jusuf and Wong, http://dx.doi.org/10.1016/j.solener.2017.06.027 0038-092X/Ó 2017 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: bdgtong@nus.edu.sg (S. Tong). Solar Energy 155 (2017) 212–223 Contents lists available at ScienceDirect Solar Energy journal homepage: www.elsevier.com/locate/solener