The paradoxical increase of Mediterranean extreme daily rainfall in spite of decrease in total values

TLDR

Earlier reports indicated that some isolated regions exhibit a paradoxical increase of extreme rainfall despite a decrease in total precipitation. Here, we conduct a coherent study of daily rainfall categories across the Mediterranean to assess whether this paradoxical behavior is real and its extent. The study examines daily rainfall categories across the Mediterranean to evaluate the paradoxical increase in extreme rainfall. Italy’s torrential rainfall (>128 mm/d) rose fourfold (1951–1995) with pronounced El Niño peaks, Spain’s extreme light and heavy categories also increased, while Israel and Cyprus showed no significant trends, highlighting a redistribution of rainfall intensity that has implications for water management, soil erosion, and flash flood risk in semi‑arid subtropical regions.

Abstract

Earlier reports indicated some specific isolated regions exhibiting a paradoxical increase of extreme rainfall in spite of decrease in the totals. Here, we conduct a coherent study of the full‐scale of daily rainfall categories over a relatively large subtropical region‐ the Mediterranean‐ in order to assess whether this paradoxical behavior is real and its extent. We show that the torrential rainfall in Italy exceeding 128 mm/d has increased percentage‐wise by a factor of 4 during 1951–1995 with strong peaks in El‐Nino years. In Spain, extreme categories at both tails of the distribution (light: 0‐4 mm/d and heavy/torrential: 64 mm/d and up) increased significantly. No significant trends were found in Israel and Cyprus. The consequent redistribution of the daily rainfall categories ‐torrential/heavy against the moderate/light intensities ‐ is of utmost interest particularly in the semi‐arid sub‐tropical regions for purposes of water management, soil erosion and flash floods impacts.