Résumé
A sample of 92 daily precipitation series was selected in the French Mediterranean region over the period 1945-2004, to study the stationarity of extreme events. The criticized series are used to define seven homogeneous climatic zones. For each one, regional series of daily peaks over threshold records are extracted from the raw data. A new adaptation of the Peak Over Threshold (POT) methodology is proposed for the search of nonstationarity. For that purpose, we suppose that the scale and occurrence parameters of the model are not constant, and linearly depend on time. This approach allows us to study the stationarity of both the occurrence and the intensity of extreme events, at the regional scale. The only statistically significant results concern an increase of the occurrence and intensity of extreme daily rains in the North of the Lozere "department" (France) and the southern part of the Auvergne, as well as an increase of the intensity of extreme rainfalls in Languedoc-Roussillon. Abstract Copyright (2007) Elsevier, B.V.