Precipitation variability in the southern Altiplano during the past 700 years: integrating instrumental records, tree rings and historical archives

MORALES, MS; CHRISTIE, DA; VILLALBA, R; PRIETO, MR; ARGOLLO, J; ALVAREZ, C; SILVA, J; PACAJES, J

Tilcara

Encuentro; Documenting, understanding and projecting changes in the hydrological cycle in the American Cordillera. IAI Collaborative Research Network 2047; 2011

Interamerican Institute for Global Change research IAI

We present a multicentury perspective of past precipitation variations in the Altiplano estimated from historical documents and a precipitation reconstruction based on Polylepis tarapacana tree-rings. The tree-ring reconstruction covers the past 700 years, and captures 54% of the instrumental precipitation variance. Spectral analysis of the tree-ring reconstruction reveals significant peaks at interannual, decadal and interdecadal periods which are in agreement with the main oscillatory modes of the instrumental records, and the Niño3.4 and PDO indices. During the 1585-1807 period the Spaniards consistently recorded the occurrence of wet/dry years because of water runoff was used to power the silver mills of Potosi, Bolivia. This past hidroclimate archive shows a remarkable similarity with the tree-ring reconstruction. The relationship between these records adds confidence on both proxies as reliable sources of precipitation variations across the Altiplano and represent a unique opportunity to better understand climate variability in this region during the past centuries.