IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
South American Altiplano hydroclimate response to volcanic eruptions over the past 700 years: a first approach using a tree-ring reconstruction
Autor/es:
MARIANO S. MORALES; RICARDO VILLALBA; MATHIAS VUILLE; ERNESTO TEJEDOR; LAIA ANDREU; ROSSANE D'ARRIGO; DUNCAN A. CHRISTIE; EUGENIA FERRERO
Lugar:
Washington DC
Reunión:
Conferencia; AGU fall meeting; 2018
Institución organizadora:
American Geophysical Union
Resumen:
Volcanic eruptions are one of the main perturbations to the Earth?s climate system. During some of these events, large amounts of sulphate aerosols are injected into the stratosphere causing a decrease on the radiative forcing. The effects of such events have been largely studied in Europe and Asia for the last millennia using tree-ring reconstructions, revealing a significant post volcanic cooling that can exceed one degree. In addition, the tree-ring reconstructions also reveal both wetting and drying responses, suggesting large impacts on precipitation on these areas. In South America (SA), hydroclimate responses to volcanic events have been mostly studied through coupled general circulation models (CGCM) in relation to El Niño?Southern Oscillation (ENSO). However, little is known about the hydroclimatic responses to past volcanic eruptions in high-resolution proxies. Here we analyze the South American Altiplano hydrological response to tropical, Southern and Northern hemisphere volcanic events over the past 7 centuries, using a set of global volcanism reconstructions and a high-resolution proxy record of hydrological conditions. We use the longest precipitation reconstruction developed with tree-ring records of Polylepis tarapacana, which is representative for western SA from 15°to 21°South and perform a superposed epoch analysis together with a Monte Carlo model. First results, including the largest volcanic events (Global Volcanic Forcing >6.49 W m-2), suggest a significant (r<0.0064) post volcanic decrease on precipitation in the year of the volcanic events and the year +1. We hypothesize that such a decrease might be related to a shift of the Intertropical Convergence Zone (ITCZ) from the preferentially forced hemisphere as a consequence of adjustments in the Hadley circulation that transports anomalous energy into the cooled hemisphere.