Spatio-temporal assessment of streamflow droughts over Southern South America: 1961-2006

RIVERA J.A., PENALBA O.C.

THEORY & APPLICATION CLIMATOLOGY

SPRINGER WIEN

Lugar: Viena; Año: 2018

0177-798X

This paper performed a streamflow drought climatologyconsidering some of the most important rivers ofSouthern South America, a region highly vulnerable to climaticvariations, based on the analysis of monthly streamflowrecords. The standardized hydrological drought index(SHDI) was used in order to depict the main characteristicsof droughts?number of drought events, mean duration, andmean severity?over the period 1961?2006. Firstly, the suitabilityof this index based on the two-parameter gamma distributionwas evaluated, considering that the use of the SHDIhas been limited over the region. The regional aspects ofstreamflow droughts were identified through a clear relationshipbetween drought frequency and its duration, indicatingdifferent temporal variations in streamflow records over thestudy area. Spatial patterns exhibit heterogeneous features interms of streamflow drought severity and can be associated tothe geographical characteristics of the basins. Observed trendsin the SSI are in line with the increases in precipitation totalsover the second half of the twentieth century over much of the study area. Nevertheless, drought conditions are observedmore often in the basins south of 40°S, in line with recenttrends in large-scale climatic oscillations. The streamflowdrought characteristics can provide critical values for differentwater-based activities, as also information to develop strategicplans that are needed for adequatewater resource managementconsidering the different climatic features over SouthernSouth America.