CR 74:15-30 (2017)  -  DOI: https://doi.org/10.3354/cr01487

ABSTRACT: The climatic characteristics of convective available potential energy (CAPE) over the Mediterranean region are studied. The data used are daily grid point (1° × 1°) values of CAPE for the period 1979-2015, obtained from the ERA-Interim data base. The main modes of the intra-annual variation and the spatial distribution of CAPE are revealed using a multivariate data reduction technique. Four main modes of intra-annual variation are found, which correspond to specific Mediterranean sub-regions: (1) the continental areas north of the Mediterranean Sea, presenting a maximum in summer and a minimum in winter; (2) the southern Mediterranean Sea and NW Africa, showing a maximum in early autumn; (3) the northern Egyptian coasts, showing a maximum in October; and (4) the continental areas of Asia Minor, characterized by maxima in late spring and early autumn and minima in winter and summer. Four main modes of spatial distribution are found, one for each season: (i) the autumn pattern presents a maximum over the southern Mediterranean Sea; (ii) the winter pattern is characterized by highest CAPE values over the NE Mediterranean Sea; (iii) the spring pattern presents maxima over the inland areas north of the Mediterranean Sea, Asia Minor and the Atlas mountains; and (iv) the summer pattern is characterized by a maximum over the Adriatic Sea. Finally, the linear trends of CAPE during the period 1979-2015 show a significant increase in many parts of the Eastern Mediterranean region, especially in the warm period.

KEY WORDS: Convective available potential energy · CAPE · Mediterranean Sea · Seasonal variability · Spatial variability · Trends