The data collected during a recent campaign conducted on the Eastern coast of Spain are used to study the entrainment process in the Thermal Internal Boundary Layer (TIBL).
The campaign BEMA aimed at determining the contribution of biogenic emissions on tropospheric ozone production was conducted in Burriana (North of Valencia, Spain) on June 1997. The campaign envisaged, other than a wide spread network of surface based measuring sites, the use of airborne instruments for the characterisation of the atmospheric circulation and chemical composition of the region.
In the present study the turbulence measurements collected by the French aircraft ARAT are used to study the structure of the TIBL developing over the area during sea breeze regime. Particular attention is given to the entrainment zone and fluxes. The use of wavelet analysis enables us to identify this portion of the layer and characterise it from the point of view of turbulent length scales. The same analysis is conducted for the bulk of the TIBL thus allowing a comparison of the turbulent transport in the two regions.
An estimate of the entrainment fluxes can be given for different scalars such as heat, moisture and ozone as well as a comparison with the surface flux values. Given the spatial structure of the TIBL developing over the coast and merging with the CBL present further inland, an interesting aspect is represented by the consequent structure of the entrainment zone and the spatial variability of the entrainment process as the TIBL develops.