Tree-ring studies in the subtropical Andes of Argentina (22‒30°S) with emphasis in hydroclimatic reconstructions

FERRERO, M.E.; VILLALBA, R.

Manaos

Workshop; Tree rings, isotopes and recent climate change in the Amazon basin; 2016

INPA (Brazil), ULeeds (UK)

Precipitationand runoff from the subtropical Andes is the main source offreshwater and rivers in northwestern Argentina and continues to beused for consumption and irrigation of agricultural fields. Theseactivities may be affected by climate variability, since analysis ofinstrumental records for the past 60 years indicate enhancedinter-annual and inter-decadal variations.Thesubtropical montane forests in northwestern Argentina display a widerange of environments along which tree growth responds differentiallyto climate. Tree-ring chronologies allow to identify the spatial andtemporal patterns of radial growth and the major climatic factorscontrolling interannual variability. In this contribution we alsopresent a long-term perspective of streamflow for the Bermejo River,a major river in the subtropical region of Argentina. The streamflowreconstruction covers the period 1680-2001 and was performed usingprincipal component regression models based on sensitive tree-ringwidth series. Composite tree-ring chronologies from Juglansaustralis, Cedrela lilloi andSchinopsislorentziiwere used to reconstruct streamflow variations. We examined thefrequency, intensity and duration of pluvials and droughts, as wellas the large-scale climate influences in our study area, indicatingthat the South American monsoon system is the main climatic source ofregional precipitation and the discharge of rivers in northernArgentina.The development of long-termreconstructions provide new information on hydroclimatic variablesfor the subtropical Andes and contribute to understanding the relatedlarge-scale atmospheric features that drive these variations.