Tree-ring based reconstruction of the southern Patagonian Andes precipitation since AD 1735

LAVERGNE, A; RICARDO VILLALBA; SRUR A. M.

Tucson

Conferencia; Second American Dendrochronology Conference; 2013

Tree-rings provide high-resolution records of past climate variations. Five regional tree-ring chronologies from Nothofagus pumilio, the dominant subalpine species in Southern Patagonia, were developed in Santa Cruz, Argentina. Sampling sites were located between 47° and 53°S along both elevation (600-1200 m) and precipitation gradients (west-to-east; 4000 to 1000 mm). In this study, we focus on determining the influence of precipitation on tree growth as a tool for potentially extending the limited instrumental precipitation records in the region. Rainfall records were used to develop a regional precipitation record. The relationships between Nothofagus pumilio growth and monthly precipitation were determined over the period 1945-2001 (56 years). Based on these relationships, a transfer function was used to reconstruct seasonal precipitation variations (October to January) over the last 275 years (AD 1735-2000). The precipitation reconstruction is dominated by interannual variability with a dry interval centered at 1920, 1950 and the end of the 20th century.