Field measurements of the convective heat transfer coefficients of impervious surfaces in the urban area

In order to understand the effect of urban impervious surface on urban heat islands and to improve the thermal environment in urban area, field measurements of the convective heat transfer characteristics on impervious surfaces in urban area was conducted in this study. The convective heat coefficients on building surfaces, pavement were measured using a novel method - naphthalene sublimation method. The results show that the convective heat transfer coefficients on urban impervious surfaces are linear relationships with the local wind velocities, and the shelter and drag effect of buildings affected the distributions of convective heat transfer coefficients. Compared with the convections on the roof of building, the convections on the vertical surface of building were less sensitive to the wind velocities and directions. On the pave road, compared with the measured points that were a little far from the wall, smaller values of convective heat transfer coefficients existed at the measured points close to the wall of the adjacent building. Certainly, many factors affect the convective heat transfer coefficient on the impervious surface in urban area. To compensate the shortage of field measurement, the numerical study of the convective heat transfer on the impervious surface will be conducted in near future.