Heat dissipation from urban surfaces to upper atmosphere is needed to be accelerated because of mitigating temperature rise in urban areas. Air turbulent measurements at three different heights above a flat roof of building were carried out, aiming to grasp the vertical heat flux in the urban canopy layer. In this paper, characteristics of air flow are discussed, because they are largely related to the vertical heat flux. The results show that upwind air flow without influence of a building configuration could be measured at a point of 5.4m distant from the windward edge and 6m high above the roof.
