Case Studies of the Wintertime Convective Boundary-Layer Structure in the Urban Area of Milan, Italy

The paper describes some aspects of the convective boundary-layer structure based on simultaneous sodar and tethersonde measurements during a field experiment in the urban area of Milan in the period 8 to 20 February, 1993. During this period, fog episodes and strong low-level elevated inversions (with lower boundaries < 400 m) were observed most of the time. A close agreement in the mixing height values, derived from the sodar and tethersonde profiles, has been achieved under these conditions. The validity of the similarity relationships, which have been originally derived to describe the vertical velocity variance and heat flux profiles over horizontally homogeneous terrain under quasi-stationary conditions, was evaluated when applied to the urban boundary layer.