Energy Calculation And Temperature Prediction Of Non-greening Surfaces In Southern Community

Urban heat island(UHI)has a bearing on inhabitants'comfort and health and urban energy.The change of urban underlying surfaces and its resulting increased surface temperature are one of the main causes of UHI.The urban surface temperature is usually calculated based on energy balance,and the applicability of the calculation methods for energy balance sub-items is therefore worth of study.Community is an organic unit of a city.Taking Guangzhou as a representative city in Southern China,this study investigated the design characteristics of the typical southern communities through a survey of 107 Guangzhou commnities,determined the typical aligned and encloused communities,as well as the hard pavement,permeable ground and landscape water body as objects,and conducted field tests in summer sunny days and data analysis based on the urban energy balance.The results show that:1)the impact of reflections on incident solar radiation is small for the southern community ground,and the root mean squre error and index of agreement are 55-68W/m~2 and close to 1 for the calculation method without considering reflections(with accurate boundary conditions);2)the commonly used four models are not applicable,and the convection heat transfer coefficient of the hard pavement is a good power function of the wind speed at 0.13m above surface;3)the performances of the Penman-Monteith and Bowen ratio methods on predicting latent heat of permeable ground are better than that of the water vapor pressure difference method,and the Bowen ratio method is most accurate;4)the water temperature prediction model established based on the energy balance and surface enerey calculation methods can be used to well predicte the time change of water surface temperature in southern community.