INVESTIGADORES
MORALES Mariano Santos
congresos y reuniones científicas
Título:
A tree-ring based reconstruction of the Southern Bolivian Altiplano precipitation since A.D. 1300
Autor/es:
MORALES, M; CHRISTIE, D; VILLALBA R; ARGOLLO J; LARA A; PACAJES J; SOLIZ C
Lugar:
FOZ DO IGUAZU
Reunión:
Congreso; THE MEETING OF THE AMERICAS; 2010
Resumen:
Instrumental
records of climate in the tropics are short, fragmentary and heterogeneous.
Longer records are needed to understand the nature of climate variations, and
how the interannual modes of tropical climate variability (such as ENSO) have
evolved under changes in long-term background conditions. Polylepis tarapacana (Rosaceae) is a small- to medium-size tree
growing on the slopes of the Andean tropical volcanoes in Bolivia and adjacent areas of Peru, Chile
and Argentina
(1723°S) between 3900 and 5200
m elevation. Previous dendrochronological studies
indicate that the radial growth of P.
tarapacana is influenced by precipitation during the summer preceding the
ring formation. Based on extensive collections of Polylepis samples across its
range of distribution, more than 15 ring width chronologies have recently been
developed. Some of these records extend for more than 700 years. Ring-width
variations from Polylepis were used as predictors of regional records of summer
precipitation across the Southern Altiplano (Fig.1). The model used for the reconstruction captures c.a.
54% of the total annual precipitation variance. The reconstruction covers the
past 700 years and captures interannual to decadal scales of variability in annual
precipitation. Several persistent droughts were observed throughout the last
700 years, as well as a negative trend in precipitation during the last 150
years.
This record represents the first dendrochronological
precipitation reconstruction for the outer tropics in South
America and demonstrates the highly significant skill of P.
tarapacana as a precipitation proxy.