Relationship between winter rainfall amount and teleconnection patterns in Southern Italy

Rainfall amounts, directly responsible for the availability of water resources in a specified area, are closely linked to the climate system. To highlight this relationship, the most important teleconnection indexes, based on the difference in sea level pressure between two geographic areas, tagged centres of climatic action, have been taken into account. In this study, the relationship between winter precipitation, registered in Calabria (Southern Italy), and atmospheric circulation was examined using a correlation analysis with several teleconnection indexes to find useful predictors. In particular, the Spearman's rank correlation test was applied as a measure of the strength of the association between the variables and the Student's t-test was used to evaluate the significance of this analysis. The results show significant and good correlations in particular with the Mediterranean Oscillation (MO), with a correlation coefficient higher than 0.6, with the North Atlantic Oscillation (NAO) and the Scandinavian (SCAND) indexes, with a correlation coefficient between 0.5 and 0.6, and with the East Atlantic West Russia (EA/WR), with a correlation coefficient between 0.4 and 0.5. The correlation is low or not significant for other teleconnection patterns. Moreover, a more detailed investigation was carried out considering five Rainfall Zones of the study area, characterised by different climatic conditions, and the correlations between the above mentioned teleconnection indexes and different Precipitation Categories. The results are interesting because they show that some indexes are closely related to low precipitation while others are linked to severe rainfall.