INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Tree-ring based reconstruction of Río Bermejo streamflow in subtropical South America
MARÍA EUGENIA FERRERO; RICARDO VILLALBA; MÓNICA DE MEMBIELA; LIDIA FERRI HIDALGO
JOURNAL OF HYDROLOGY
ELSEVIER SCIENCE BV
Lugar: Amsterdam; Año: 2015 vol. 525 p. 572 - 572
Precipitation on the subtropical Andes in northwestern Argentina is the main source of freshwater to rivers,which provide water for consumption, hydroelectric generation and irrigation of agricultural fields.Regional streamflow records for the past 60 years indicate a period of enhanced inter-annual andinter-decadal variability during recent decades. Here we present a long-term perspective of streamflowvariations for Río Bermejo, a major river in the subtropics of Argentina?Bolivia. This streamflow reconstructioncovers the period 1680?2001 and was performed using principal component regression modelsbased on precipitation sensitive tree-ring width series. Composite tree-ring chronologies from Juglansaustralis, Cedrela lilloi and Schinopsis lorentzii were used as predictors to reconstruct the May?October(dry season) streamflow variations. Monthly instrumental streamflow records were used to assess thetemporal relationship between climatic data and tree-ring records. The regression model explains 52%of the variance of May?October Bermejo discharge (R2 adj = 0.499) over the period 1941?1992.Analyses of the frequency, intensity and duration of pluvials and droughts indicates a sustained increasein streamflow since the 1960s, which is exceptional since 1680. Pearson?s correlation coefficientsbetween Río Bermejo records against gridded interpolated precipitation and outgoing longwave radiationindicate that the South American monsoon is the main source of regional precipitation and the consequentdischarge of subtropical rivers in northern Argentina. Long-term streamflow reconstructions insubtropical South America contribute to our understanding of past and present climate variations andthe related large-scale atmospheric features that drive these variations.