A simple model of summer atmospheric circulation in the Po Valley

Through numerical integration of the primitive equations, we study the summer circulation in the Po Valley, Italy. We investigate separately the mountain slope effect and the sea-breeze effect. The results show that, because of the mountain slope, there is convergence early in the morning and divergence during the day in the lower atmosphere. Further-more, the sea breeze generated by the Adriatic Sea is confined to the eastern side of the Valley. These two phenomena are expected. However, the model suggests that the convergence due to the slope is organized in an area as large as the valley and that, even if the sea breeze is a boundary layer circulation, the perturbation introduced triggers a train of gravity waves as deep as the troposphere. These effects might be very important for the distribution of the summer thunderstorms. Further specific investigations. Experimental and theoretical, are needed.