Statistical Analysis of Heavy Rains and Floods around the French Mediterranean Basin over One Half a Century of Observations

Abstract

The French region adjacent to the Mediterranean basin is vulnerable to hydrological risks generated by convective precipitation in the form of heavy rainfall and conditioned by the configuration of the relief. These risks are driven by the increase in sea water temperature over the last half century, which itself has been more pronounced since 1990. The statistical analysis on the frequency of rainfall intensity in a 24 to 48 h interval, correlated with the NAO, WMOI and SSTMED indices shows a recrudescence of rainfall amounting to more than 100 mm, which leads to the genesis of floods and flash floods. Furthermore, there has been a higher frequency of floods and disasters in this period. The intensity of material and human damage recorded following such local Cévennes-type phenomena is also due to urban development and population growth.