Regional aspects of streamflow droughts in the Andean rivers of Patagonia, Argentina. Links with large-scale climatic oscillations

2. RIVERA J.A., ARANEO D.C., PENALBA O.C., VILLALBA R

HYDROLOGY RESEARCH

I W A PUBLISHING

Año: 2017

0029-1277

Under the current global warming trend, droughts are expected to increase, with serious implicationsfor water resources management. This study analyzed the regional aspects of droughts in terms ofstreamflow deficiencies over the Andean rivers of Patagonia, Argentina. Based on the variablethreshold level method, the main characteristics of streamflow droughts were obtained for thehydrological years 1962/63?2014/15, considering three different severity levels over 11representative basins. Two distinct regional behaviors were identified in terms of temporal variationsof streamflow drought duration and its cumulative deficit volume, dividing the study area into Northand Central Patagonia. The effects of the Southern Annular Mode (SAM), the El Niño?SouthernOscillation (ENSO), and the Pacific Decadal Oscillation (PDO) on the interannual and interdecadalvariability of streamflow droughts were assessed through an empirical decomposition applied to theregional time series. These large-scale climatic oscillations have a distinct regional and temporalbehavior in terms of the modulation of streamflow drought variability. Considering the interannualstreamflow drought variability, the El Niño signal is more consistent and contributes with humidconditions, especially over North Patagonia. The multi-decadal component of the streamflow droughttime series is linked to the upward trend in SAM, particularly over Central Patagonia.