T. Littmann, An empirical classification of weather types in the Mediterranean Basin and their interrelation with rainfall, THEOR APP C, 66(3-4), 2000, pp. 161-171
This paper presents: a classification of weather types in the Mediterranean
Basin based on cluster analysis of the daily occurrences of several surfac
e pressure centers and the subjective identification of 500hPa trough axis
positions (1992-1996). The procedure results in 20 types that explain 69% o
f overall pressure center variance and which are consistent with the season
al succession of regional circulation. The development of weather types in
winter is primarily controlled by the eastward propagation of barotropic wa
ves while departures from the zonal Row pattern in summer tend to be linked
to blocked stationary pools. H1-types with anticyclonic circulation in the
Western Mediterranean and cyclonic flow in the eastern part are well inter
related with zonal and anticyclonic general weather types in Central Europe
. H2-types featuring a weak Azores Anticyclone interrelate with a variety o
f meridional circulation types after the Hess and Brezowski (1969) classifi
cation. The 20 types explain rainfall variance in the core Mediterranean re
gions las defined by principal components) to a high degree while rainfall
variance in marginal regions is influenced by circulation patterns not bein
g typical fur the Mediterranean Basin.