INVESTIGADORES
MORALES Mariano Santos
congresos y reuniones científicas
Título:
Precipitation variability in the Southern Altiplano during the past 700 years: integrating instrumental records, tree-rings and historical archives
Autor/es:
MORALES, M; CHRISTIE, D; VILLALBA, R; ARANEO, D; PRIETO, M.R; GIODA, A; ALVAREZ C; SILVA J
Lugar:
Valdivia
Reunión:
Conferencia; II International Symposium Reconstructing Climate Variations in South America and the Antartic Peninsula over the last 2000 years; 2010
Institución organizadora:
PAGES Past Global changes
Resumen:
Precipitation variations in the Altiplano have direct human and environmental
impacts, often being associated with droughts and loods. Instrumental
records of climate in the tropics are short, fragmentary and heterogeneous. In
this study we present a multi-century perspective of past precipitation variations
in the Altiplano estimated from historical documents and a precipitation
reconstruction based on Polylepis tarapacana tree-rings. The atmospheric
circulation patterns associated with precipitation variations over the region
were also analyzed. Previous dendrochronological studies have demonstrated
the high skill of P. tarapacana as a proxy for precipitation. The radial growth of
this tree species is strongly inluenced by moisture availability, representing
an excellent proxy for past precipitation. 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 signiicant
peaks at interannual, decadal and interdecadal scales which are in agreement
with the main oscillatory modes recorded in instrumental records, and the
Niño3.4 and PDO indices. In agreement with previous studies, analysis of the
main ocean-atmospheric circulation patterns associated with reconstruction
show the strong inluence of the tropical Paciic on determining dry and wet
events across the Altiplano. As water runoff was used to power the silver
mills of Potosi, the Spaniards consistently recorded the occurrence of wet/
dry years during the 1585-1807 period in Bolivia. This valuable past hidroclimatic
archive show a remarkable similarity with the tree-ring reconstruction.
The signiicant relationship between these records adds conidence on both
proxies as reliable sources of precipitation variations across the Bolivian Altiplano
and provides a unique opportunity to better understand climate variability in this region during the past centuries