Field measurements on energy balance of an urban canyon in the summer season

Field measurements on the energy balance of an east-west oriented urban canyon were performed continuously for several days in the summer season, as preliminary research of the heat transfer in the urban atmospheric boundary layer. The urban canyon consisted of concrete buildings, 16 m high and partially covered with windows, standing face to face across an asphalt road 17 m wide. The energy balance of the urban canyon is represented by the balance at the imaginary surface named "the top surface". The top surface is a plane above the canyon at the same level as the roof surface of the buildings. In the daytime, the energy budget into the top surface is much larger than that into the roof surface. At nighttime, there is no significant difference in the energy balance between the roof surface and the top surface.