University of Oulu

Aron, P. G., Li, S., Brooks, J. R., Welker, J. M., & Levin, N. E. (2023). Seasonal variations in triple oxygen isotope ratios of precipitation in the western and central United States. Paleoceanography and Paleoclimatology, 38, e2022PA004458.

Seasonal variations in triple oxygen isotope ratios of precipitation in the western and central United States

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Author: Aron, P. G.1,2; Li, S.3; Brooks, J. R.4;
Organizations: 1Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
2Now at Hazen and Sawyer, Baltimore, MD, USA
3School of Earth and Space Sciences, Institute of Geochemistry, Peking University, Beijing, China
4Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Corvallis, OR, USA
5Department of Biological Sciences, University of Alaska, Anchorage, AK, USA
6Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
7University of the Arctic (UArctic), Rovaniemi, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.1 MB)
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Language: English
Published: American Geophysical Union, 2023
Publish Date: 2023-09-29


Triple oxygen isotope ratios (∆′17O) offer new opportunities to improve reconstructions of past climate by quantifying evaporation, relative humidity, and diagenesis in geologic archives. However, the utility of ∆′17O in paleoclimate applications is hampered by a limited understanding of how precipitation ∆′17O values vary across time and space. To improve applications of ∆′17O, we present δ18O, d-excess, and ∆′17O data from 26 precipitation sites in the western and central United States and three streams from the Willamette River Basin in western Oregon. In this data set, we find that precipitation ∆′17O tracks evaporation but appears insensitive to many controls that govern variation in δ18O, including Rayleigh distillation, elevation, latitude, longitude, and local precipitation amount. Seasonality has a large effect on ∆′17O variation in the data set and we observe higher seasonally amount-weighted average precipitation ∆′17O values in the winter (40 ± 15 per meg [± standard deviation]) than in the summer (18 ± 18 per meg). This seasonal precipitation ∆′17O variability likely arises from a combination of sub-cloud evaporation, atmospheric mixing, moisture recycling, sublimation, and/or relative humidity, but the data set is not well suited to quantitatively assess isotopic variability associated with each of these processes. The seasonal ∆′17O pattern, which is absent in d-excess and opposite in sign from δ18O, appears in other data sets globally; it showcases the influence of seasonality on ∆′17O values of precipitation and highlights the need for further systematic studies to understand variation in ∆′17O values of precipitation.

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Series: Paleoceanography and paleoclimatology
ISSN: 2572-4517
ISSN-E: 2572-4525
ISSN-L: 2572-4517
Volume: 38
Issue: 4
Article number: e2022PA004458
DOI: 10.1029/2022PA004458
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: Acknowledgment is made to the donors of the American Chemical Society Petroleum Research Fund for partial support of this research (ACS PRF# 52642-DNI2), in addition to funding support from Johns Hopkins University. Phoebe Aron received support from Chris Poulsen at the University of Michigan and funding from the Heising-Simons Foundation. Funding from NSF MRI to JMW (# 0953271) supported the USNIP sample analysis at the University of Alaska Anchorage.
Dataset Reference: All isotope data from this study are available on the University of Utah Water Isotope Database under Project ID 00388 (Aron et al., 2023), 00011 (Brooks et al., 2012b), and 00016 (Brooks, 2017).
Copyright information: © 2023. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.