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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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Central Equatorial Pacific Warming and Freshening in the Twentieth Century: Insights From a Coral Ensemble Approach
Abstract The tropical Pacific influences climate patterns across the globe, yet robust constraints on decadal to centennial‐scale climate variations are difficult to extract from sparse instrumental observations in this region. Oxygen isotope (δ18O) records from long‐lived corals enable the quantitative reconstruction of tropical Pacific climate variability and trends over the twentieth century and beyond, but such corals are exceedingly rare. Here, we use multiple short coral δ18O records to create a coral ‘ensemble’ reconstruction of twentieth century climate in the central tropical Pacific. Ten U/Th‐dated fossil coral δ18O records from Kiritimati Island (2°N, 157°W) span 1891 CE to 2006 CE, with the younger samples enabling quantitative comparison to a large ensemble of modern coral records and instrumental sea surface temperature. A composite record constructed of modern and fossil Kiritimati coral δ18O records shows a shift toward warmer and fresher conditions from 1970 CE onward, consistent with previously published records in this region.
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- Award ID(s):
- 2002509
- PAR ID:
- 10385519
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 1
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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