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What drives interannual variation in tree ring oxygen isotopes in the Amazon?
Author(s) -
Baker J. C. A.,
Gloor M.,
Spracklen D. V.,
Arnold S. R.,
Tindall J. C.,
Clerici S. J.,
Leng M. J.,
Brienen R. J. W.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071507
Subject(s) - amazon rainforest , precipitation , environmental science , structural basin , paleoclimatology , amazon basin , isotopes of oxygen , stable isotope ratio , climatology , atmospheric sciences , atmospheric circulation , geology , climate change , geography , meteorology , oceanography , geomorphology , ecology , physics , biology , geochemistry , quantum mechanics
Abstract Oxygen isotope ratios in tree rings (δ 18 O TR ) from northern Bolivia record local precipitation δ 18 O and correlate strongly with Amazon basin‐wide rainfall. While this is encouraging evidence that δ 18 O TR can be used for paleoclimate reconstructions, it remains unclear whether variation in δ 18 O TR is truly driven by within‐basin processes, thus recording Amazon climate directly, or if the isotope signal may already be imprinted on incoming vapor, perhaps reflecting a pan‐tropical climate signal. We use atmospheric back trajectories combined with satellite observations of precipitation, together with water vapor transport analysis to show that δ 18 O TR in Bolivia are indeed controlled by basin‐intrinsic processes, with rainout over the basin the most important factor. Furthermore, interannual variation in basin‐wide precipitation and atmospheric circulation are both shown to affect δ 18 O TR . These findings suggest δ 18 O TR can be reliably used to reconstruct Amazon precipitation and have implications for the interpretation of other paleoproxy records from the Amazon basin.