Flash flood reconstruction in the Eastern Mediterranean: Regional tree ring-based chronology and assessment of climate triggers on the island of Crete

摘要

The past geomorphic activity of flash floods in the Eastern Mediterranean has been poorly understood. Despite the general increase in mean annual temperature and decrease in annual precipitation totals, intense rainfall during strong cyclogenesis is still expected under a changing climate. The aim of this study was to identify past flash flood events on the island of Crete (Greece) to (i) create a regional chronology of flash floods using dendrogeomorphic dating and (ii) describe climate triggers responsible for the most distinct events. The sampling of 398 trees and shrubs from eight catchments enabled the reconstruction of 76 flash flood events over 43 different years. The length of the chronologies ranged from 27 to 125 years, and the most distinct events were recorded in the 1993-94, 2000-01, and 2006-07. Significant differences (p < 0.00001) in the ages of sampled trees and the bark thickness among the catchments resulted in different lengths of chronologies and numbers of identified events. Records from selected rain gauges were used to identify precipitation patterns associated with flash floods. The low propagation velocities of cyclones originating south and west of Crete characterised the most distinct flash flood events, based on synoptic scale analyses.