Summer daily circulation in the Po Valley, Italy

Abstract

Surface wind data from a network of stations located in the Po Valley, Italy, have been analysed in order to investigate the features of the local circulation during summer, under synoptic conditions of weak pressure gradients. The up-valley wind appears to be closely coupled with the sea-land breeze in the eastern part of the valley. The nocturnal phase winds are almost completely absent in the central part of the valley. An anomalous nocturnal circulation in the northeastern part of the valley is tentatively related to the influence of a low-level jet developing in a near plain. Due to the differential heating of the mountain slopes and the valley floor, the flow is divergent and anticyclonic during the day and convergent and cyclonic at night.