In the frame of the Basel Urban Boundary Layer Experiment (BUBBLE) flux measurements are carried out in the city of Basel (Switzerland) over one year to increase the understanding of exchange processes over urban surfaces. Details of the project (scientific goals, instrumentation and participants) can be found in Rotach (2002, same conference). The measurements will last to Sep 2002 with a continuously operated flux measurement network. This presentation focuses on latent and sensible heat flux measurements from selected sites including suburban and European downtown. The sites are equipped with at least one level of fast hygrometers. Sensible flux is calculated from sonic data. All measurements are carried out at approximately two times the building height, where also a net radiation sensor is installed. First results discuss the partitioning of turbulent energy over the different surfaces.