More Like this

1. Measurements of ¹⁸ O ¹⁸ O and ¹⁷ O ¹⁸ O in the atmosphere and the role of isotope-exchange reactions: ¹⁸ O ¹⁸ O AND ¹⁷ O ¹⁸ O IN THE ATMOSPHERE

   https://doi.org/10.1029/2012JD017992  

   Yeung, Laurence Y.; Young, Edward D.; Schauble, Edwin A. (September 2012, Journal of Geophysical Research: Atmospheres)
2. Summer and nonsummer climatic signals in speleothem δ ¹⁸ O revealed by loess microcodium δ ¹⁸ O in East Asia

   https://doi.org/10.1073/pnas.2425565122  

   Zhang, Zeke; Liu, Zhengyu; Li, Gaojun; Cai, Yanjun; Wen, Qin; Cheng, Hai; Lawrence_Edwards, R.; Lei, Jing; Liu, Heng; Jing, Zhaowei; et al (July 2025, Proceedings of the National Academy of Sciences)

   Speleothem δ¹⁸O records from central southern China have long been regarded as a key benchmark for Asian summer monsoon intensity. However, the similar δ¹⁸O minima observed among precession minima and their link to seasonal precipitation mixing remains unclear. Here, we present a 400,000-y record of summer precipitation δ¹⁸O from loess microcodium, which captures distinct precession cycles similar to those seen in speleothem δ¹⁸O records, particularly during glacial periods. Notably, our microcodium δ¹⁸O record reveals very low-δ¹⁸O values during precession minima at peak interglacials, a feature absent in speleothem δ¹⁸O records from central southern China. This discrepancy suggests that the mixed summer and nonsummer climatic signals substantially influence the speleothem δ¹⁸O records from central southern China. Proxy-model comparisons indicate that the lack of very low-δ¹⁸O values in speleothem δ¹⁸O records is due to an attenuated summer signal contribution, resulting from a lower summer-to-annual precipitation ratio in southern China at strong monsoon intervals. Our findings offer a potential explanation for the long-standing puzzle of the absence of 100- and 41-kyr cycles in speleothem δ¹⁸O records and underscore the critical role of seasonality in interpreting paleoclimatic proxies in central southern China. These insights also have broader implications for interpreting speleothem δ¹⁸O records globally, advocating for a more multiseason interpretive framework. 

   more » « less
3. Variability and Controls on δ ¹⁸ O, d‐excess, and ∆′ ¹⁷ O in Southern Peruvian Precipitation

   https://doi.org/10.1029/2020JD034009  

   Aron, Phoebe G.; Poulsen, Christopher J.; Fiorella, Richard P.; Levin, Naomi E.; Acosta, Rene P.; Yanites, Brian J.; Cassel, Elizabeth J. (December 2021, Journal of Geophysical Research: Atmospheres)

   Abstract The isotopic composition of precipitation is used to trace water cycling and climate change, but interpretations of the environmental information recorded in central Andean precipitation isotope ratios are hindered by a lack of multi‐year records, poor spatial distribution of observations, and a predominant focus on Rayleigh distillation. To better understand isotopic variability in central Andean precipitation, we present a three‐year record of semimonthly δ¹⁸O_pand δ²H_pvalues from 15 stations in southern Peru and triple oxygen isotope data, expressed as ∆′¹⁷O_p, from 32 precipitation samples. Consistent with previous work, we find that elevation correlates negatively with δ¹⁸O_pand that seasonal δ¹⁸O_pvariations are related to upstream rainout and local convection. Spatial δ¹⁸O_pvariations and atmospheric back trajectories show that both eastern‐ and western‐derived air masses bring precipitation to southern Peru. Seasonal d‐excess_pcycles record moisture recycling and relative humidity at remote moisture sources, and both d‐excess_pand ∆′¹⁷O_pclearly differentiate evaporated and non‐evaporated samples. These results begin to establish the natural range of unevaporated ∆′¹⁷O_pvalues in the central Andes and set the foundation for future paleoclimate and paleoaltimetry studies in the region. This study highlights the hydrologic understanding that comes from a combination of δ¹⁸O_p, d‐excess_p, and ∆′¹⁷O_pdata and helps identify the evaporation, recycling, and rainout processes that drive water cycling in the central Andes. 

   more » « less
4. Equatorial Undercurrent Influence on Surface Seawater δ ¹⁸ O Values in the Galápagos

   https://doi.org/10.1029/2022GL102074  

   Conroy, Jessica_L; Murray, Nicole_K; Patterson, Gillian_S; Schore, Aiden_I_G; Ikuru, Ima; Cole, Julia_E; Chillagana, David; Echeverria, Fernando (February 2023, Geophysical Research Letters)

   Abstract Stable isotopes of oxygen (δ¹⁸O) in seawater reflect the combined influences of ocean circulation and atmospheric moisture balance. However, it is difficult to disentangle disparate ocean and atmosphere influences on modern seawater δ¹⁸O values, partly because continuous time series of seawater δ¹⁸O are rare. Here we present a nearly nine‐year, continuous record of seawater δ¹⁸O values from the Galápagos. Seawater δ¹⁸O values faithfully track sea surface salinity and salinity along the equator at 50 m depth. Zonal current velocity within the Equatorial Undercurrent (EUC), directly west of the Galápagos, is strongly correlated with Galápagos surface seawater δ¹⁸O values with a 1‐month lag. Reconstructions of Galápagos seawater δ¹⁸O values could thus provide a window into past variations in the strength of the EUC, an important influence on large‐scale tropical Pacific climate. 

   more » « less
5. Branching Ratio Measurements for Vacuum Ultraviolet Photodissociation of ¹² C ¹⁶ O

   https://doi.org/10.1021/jp400412n  

   Gao, Hong; Song, Yu; Chang, Yih-Chung; Shi, Xiaoyu; Yin, Qing-Zhu; Wiens, Roger C.; Jackson, William M.; Ng, C. Y. (July 2013, The Journal of Physical Chemistry A)