Observational studies of turbulent transfer processes across the urban canopy

The role of the urban canopy on the turbulent transfer of heat and momentum in the urban boundary layer is studied. Measurements are collected over a morphologically ideal street canyon using a displaced-beam small-aperture scintillometer. The measurements are complemented with those from thirteen sonic anemometers placed strategically over rooftops and in the street canyon. Data were collected over a period of several weeks during the spring of 2010. Comparisons between sonic (in-situ) and scintillometer (path-averaged) observations show how different sections of the canopy contribute to the integral heat and momentum transfer between the urban canopy and boundary layer above. The influence of wind direction and atmospheric stability on the transfer processes is also investigated. Considering future applications on the improvement of the parameterization of urban areas in mesoscale models, the study also opens the possibility to develop expressions for the estimation of the integral effects of the urban canopy on turbulent transfer processes under different conditions when only point measurements are available.