Boundary layer development and summer circulation in Southern Portugal

Abstract

The summer circulation in Southwest Iberia is studied with data from a field experiment and numerical simulations by the non-hydrostatic mesoscale model, Meso-NH. The model is initialized and forced by the ARPEGE numerical weather prediction model. Surface fields and parameters were obtained from a number of different sources and validated against observations and long period integrations of the land surface model. The numerical simulations are found to capture most of the features found in surface and upper air observations, indicating the importance of the sea-breeze circulation in the diurnal cycle of the atmospheric boundary layer in regions more than 100 km away from the coast. The 3D nature of the summer atmospheric circulation over South Portugal is examined using results from a real case simulation of two summer typical days. Budget analysis in the 3D model are also shown, and used to clarify the relative importance of turbulent fluxes and horizontal advection in the dynamics of the boundary layer. This article was written in 2001. For various reasons it was never published, even though part of its content is published in Portuguese in the first author's PhD thesis, defended in 2006. The work was performed with an old version of Meso-NH, but we are convinced that their main results are up to date, which justifies its publication in English in an international scientific journal. Meanwhile, one of the authors, Joel Noilhan passed away too soon. The publication of this manuscript is also a small tribute to Joel and his scientific legacy.