Secular variations of the synoptic circulation over the Iberian Peninsula

In this paper the long-term evolution of the synoptic circulation over the Iberian Peninsula is analysed by applying an automated synoptic classification procedure. At the annual scale, the substitution of NE situations by SE situations reflects a replacement of maritime blockings by continental blockings. In summer, the decrease of "Atlantic" types and the correlative increase of easterly and cyclonic days could be related to a strengthening of the subtropical circulation. The synoptic types have also experienced a strong within-type variability due to the influence of large scale circulation patterns, like the North Atlantic Oscillation. The results show that the Polar Front controls not only the frequency of occurrence of each synoptic type, but also the deepening of the lows and the strength of the anticyclones.