Comparison of Aggregated and Measured Turbulent Fluxes in an Urban Area

Most of the parameters commonly used to describe the turbulence in the atmospheric boundary layer represent conditions of atmospheric turbulence near the ground and therefore have a small footprint. For a mast of 10 meters above ground the footprint is few hundred meters. A 40-50 meter mast looks over some kilometers in upwind direction. The height of the convective boundary layer is typically 1-2 kilometers in middle latitudes and reflects the conditions several tens of kilometers upwind. The footprint of meteorological characteristics is essentially dependant on atmospheric stability and wind speed (Gryning and Batchvarova, 1999; Kljun et al., 2003).