Abstract
Abstract. Modeling of extremes dry spells in Northern Tunisia, in order to
detect the severity of the phenomenon, is carried out. Dry events are
considered as a sequence of dry days (below a threshold) separated by
rainfall events from each other. The maximum dry event duration follows the
Generalized Extreme Value distribution. The data series adherence to the
probability distribution was verified by the Anderson-Darling test. The
positive trend and non-stationarity of dry spells was verified respectively
by the Mann–Kendall test and Dickey–Fuller and augmented Dickey–Fuller
tests. The irregular distribution of rainfall in the growing season for Sidi
Abdelbasset station has increased the number of dry spells. The increase of
rainy days in Ghézala dam and Sidi Salem gauge stations resulted in a
decrease of dry spells in this area. Regarding the return period of one year
(wet season), dry events occurred from 14 to 27 d in this region
constitute an agricultural potential risk. The Southern region was the most
vulnerable.