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

Copernicus Publications

Año: 2018 vol. 22 p. 3155 - 3174

This study examines the joint variability of precipitation, river streamflow and temperature over northeastern Argentina; advances the understanding of their links with global SST forcing; and discusses their impacts on water resources, agriculture and human settlements. The leading patterns of variability, their nonlinear trends, and cycles are identified by means of a Principal Component Analysis (PCA) complemented with a Singular Spectrum Analysis (SSA). Interannual hydroclimatic variability centres on two broad frequency bands: one of 2.5-6.5 years corresponding to El Niño Southern Oscillation (ENSO) periodicities and the second of about 9 years. The higher frequencies of the precipitation variability (2.5-4 years) favoured extreme events after 2000, even during moderate extreme phases of the ENSO. Minimum temperature is correlated with ENSO with a main frequency close to 3 years. Maximum temperature time series correlates well with SST variability over the Southern Atlantic, Indian and Pacific Oceans with a 9-year frequency. Interdecadal variability is characterized by low-frequency trends and multidecadal oscillations that have induced a transition from dryer and cooler climate to wetter and warmer decades starting in the mid-twentieth century. The Paraná River streamflow is influenced by North and South Atlantic SSTs with bi-decadal periodicities.The hydroclimate variability at all time scales had significant sectoral impacts. Frequent wet events between 1970 and 2005 favoured floods that affected agricultural and livestock productivity and forced population displacements. On the other hand, agricultural droughts resulted in soil moisture deficits that affected crops at critical growth stages. Hydrological droughts affected surface water resources causing water and food scarcity and stressed the capacity for hydropower generation. Lastly, increases in minimum temperature reduced wheat and barley yields.