Interannual-to-multidecadal Hydroclimate Variability and its Sectoral Impacts in northeastern Argentina

LOVINO, MIGUEL A.; MÜLLER, OMAR V.; MÜLLER, GABRIELA V.; SGROI, LEANDRO C.; BAETHGEN, WALTER E.

Hydrology and Earth System Sciences Discussions

Copernicus

Año: 2018 vol. 22 p. 3155 - 3174

This study examines the joint variability of precipitation, riverstreamflow and temperature over northeastern Argentina; advances theunderstanding of their links with global SST forcing; and discussestheir impacts on water resources, agriculture and human settlements.The leading patterns of variability, and their nonlinear trends andcycles are identified by means of a principal component analysis(PCA) complemented with a singular spectrum analysis (SSA).Interannual hydroclimatic variability centers on two broad frequencybands: one of 2.5?6.5 years corresponding to El Niño SouthernOscillation (ENSO) periodicities and the second of about 9 years. Thehigher frequencies of the precipitation variability (2.5?4 years)favored extreme events after 2000, even during moderate extremephases of the ENSO. Minimum temperature is correlated with ENSO witha main frequency close to 3 years. Maximum temperature time seriescorrelate well with SST variability over the South Atlantic, Indianand Pacific oceans with a 9-year frequency. Interdecadal variabilityis characterized by low-frequency trends and multidecadaloscillations that have induced a transition from dryer and coolerclimate to wetter and warmer decades starting in the mid-twentiethcentury. The Paraná River streamflow is influenced by North andSouth Atlantic SSTs with bidecadal periodicities. The hydroclimate variability at all timescales had significant sectoralimpacts. Frequent wet events between 1970 and 2005 favored floodsthat affected agricultural and livestock productivity and forcedpopulation displacements. On the other hand, agricultural droughtsresulted in soil moisture deficits that affected crops at criticalgrowth stages. Hydrological droughts affected surface waterresources, causing water and food scarcity and stressing the capacityfor hydropower generation. Lastly, increases in minimum temerature reduced wheat and barley yields.