Three pairs of ultrasonic anemometers were deployed above a roof top, during summer time, deep within an urban fetch. Each pair was mounted at a heights of 2 and 6 meters above the roof level. The pairs where seven meters apart from each other, thus occupying a third of the roof length. The roof height was roughly 10 meters above the street level, so that in terms of normalized heights the measurments were performed at 1.2 and 1.6. The sampling rates of all anemometers was 10Hz and data were collected on the same card to ensure synchronization. Analysis of turbulent fluxes was performed and compared to its counterpart in an open area.