Regional droughts in southern South America

From a regional inventory of monthly droughts, which was evaluated in six regions of southern South America, the seasonal occurrence of the phenomenon and its persistence together with the duration of monthly and annual sequences, extreme events, and other statistical estimates of the proposed index have been studied. In a primary analysis, it is possible to observe that regions present different behaviors regarding the duration of dry sequences, with more persistence in the Argentinean continental region. Temporal behaviors of the annual indexes have also been analyzed, in the attempt to determine any aspects of the impact of global warming. Through this analysis, the presence of long favorable tendencies regarding precipitations or the inverse of droughts occurrence are confirmed for the eastern Andes Mountains in Argentina (ARG) with its five sub-regions (Northwest Argentina-NWA, Northeast Argentina-NEA, Humid Pampa-HP, West-Centre Provinces-WC and Patagonia-PAT, and the inverse over the central region of Chile (CHI). Other climatic great-scale changes are interdecadales variations and variances explained according to ENSO.