Multi-decadal changes and Pan-American coherence of precipitation sensitive tree-ringchronologies from the eastern Amazon
Multi-decadal changes and Pan-American coherence of precipitation sensitive tree-ringchronologies from the eastern Amazon
Thursday, 3 December 2020: 07:19
Abstract:
The development of two new climate proxies from tropical tree-ring chronologies of Cedrela odorata in the eastern Amazon has been recently reported and used to reconstruct the past 258-years of wet season precipitation in the Amazon basin. The annual resolution of these tree-ring chronologies is indicated by the strong crossdating among trees at two collection sites near the Rio Paru. This is supported by the significant correlation between the numerical ring-width chronologies for each site, the significant correlations with regional precipitation totals, and the Amazon-wide pattern of above and below average wet season precipitation during high and low growth extremes in both chronologies. The longest reconstruction extends from 1759-2016 and exhibits significant multi-decadal variance with a period of approximately 35-years. Cedrela low
growth and low wet season precipitation extremes are linked with significant positive anomalies in sea surface temperatures in the eastern tropical Pacific typical of El Niño conditions. Pan-American precipitation extremes of opposite sign are detected when the Cedrela chronologies
from the eastern Amazon are compared with moisture-sensitive tree-ring chronologies from midlatitude North and South America. Inter-hemispheric coherence of precipitation and tree growth appears to be stronger during El Niño events, and several consecutive reconstructed drought
extremes in the eastern Amazon are associated with prolonged El Niño events. The multi-decadal rainfall regimes appear to reflect a low-frequency component of natural variability capable of modulating the ENSO forcing of Pan-American precipitation anomalies.
growth and low wet season precipitation extremes are linked with significant positive anomalies in sea surface temperatures in the eastern tropical Pacific typical of El Niño conditions. Pan-American precipitation extremes of opposite sign are detected when the Cedrela chronologies
from the eastern Amazon are compared with moisture-sensitive tree-ring chronologies from midlatitude North and South America. Inter-hemispheric coherence of precipitation and tree growth appears to be stronger during El Niño events, and several consecutive reconstructed drought
extremes in the eastern Amazon are associated with prolonged El Niño events. The multi-decadal rainfall regimes appear to reflect a low-frequency component of natural variability capable of modulating the ENSO forcing of Pan-American precipitation anomalies.