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Abstract Tropical South American climate is influenced by the South American Summer Monsoon and the El Niño Southern Oscillation. However, assessing natural hydroclimate variability in the region is hindered by the scarcity of long-term instrumental records. Here we present a tree-ringδ18O-based precipitation reconstruction for the South American Altiplano for 1700–2013 C.E., derived fromPolylepis tarapacanatree rings. This record explains 56% of December–March instrumental precipitation variability in the Altiplano. The tree-ringδ18O chronology shows interannual (2–5 years) and decadal (~11 years) oscillations that are remarkably consistent with periodicities observed in Altiplano precipitation, central tropical Pacific sea surface temperatures, southern-tropical Andean ice coreδ18O and tropical Pacific coralδ18O archives. These results demonstrate the value of annual-resolution tree-ringδ18O records to capture hydroclimate teleconnections and generate robust tropical climate reconstructions. This work contributes to a better understanding of global oxygen-isotope patterns, as well as atmospheric and oceanic processes across the tropics.
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Volcanic Eruption Signatures in the Isotope‐Enabled Last Millennium Ensemble
Abstract Explosive volcanic eruptions are one of the largest natural climate perturbations, but few observational constraints exist on either the climate responses to eruptions or the properties (size, hemispheric aerosol distribution, etc.) of the eruptions themselves. Paleoclimate records are thus important sources of information on past eruptions, often through the measurement of oxygen isotopic ratios (δ18O) in natural archives. However, since many processes affectδ18O, the dynamical interpretation of these records can be quite complex. Here we present results from new, isotope‐enabled members of the Community Earth System Model Last Millennium Ensemble, documenting eruption‐inducedδ18O variations throughout the climate system. Eruptions create significant perturbations in theδ18O of precipitation and soil moisture in central/eastern North America, via excitation of the Atlantic Multidecadal Oscillation. Monsoon Asia and Australia also exhibit strong precipitation and soilδ18O anomalies; in these cases,δ18O may reflect changes to El Niño‐Southern Oscillation phase following eruptions. Salinity and seawaterδ18O patterns demonstrate the importance of both local hydrologic shifts and the phasing of the El Niño‐Southern Oscillation response, both along the equator and in the subtropics. In all cases, the responses are highly sensitive to eruption latitude, which points to the utility of isotopic records in constraining aerosol distribution patterns associated with past eruptions. This is most effective using precipitationδ18O; all Southern eruptions and the majority (66%) of Northern eruptions can be correctly identified. This work thus serves as a starting point for new, quantitative uses of isotopic records for understanding volcanic impacts on climate.
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- Award ID(s):
- 1805143
- PAR ID:
- 10459181
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Paleoceanography and Paleoclimatology
- Volume:
- 34
- Issue:
- 8
- ISSN:
- 2572-4517
- Page Range / eLocation ID:
- p. 1534-1552
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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