Wan et al. (2026) Stable Isotope Record of Precipitation Dynamics in the Semi‐Arid Subtropics

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Journal of Geophysical Research Atmospheres
• Year: 2026
• Date: 2026-03-25
• Authors: Chengwei Wan, Shawan Dogramaci, Jennifer Gleeson, Paul Hedley, Pauline F. Grierson, J. J. Gibson, Grzegorz Skrzypek
• DOI: 10.1029/2025jd044431

Research Groups

[Information not available in the provided abstract.]

Short Summary

This study investigated rainfall stable isotope variability in subtropical northwest Australia over 10 years to understand precipitation mechanisms and moisture sources, identifying a significant "amount effect," substantial sub-cloud evaporation, and significant land evapotranspiration recycling.

Objective

• To examine the variability in rainfall stable hydrogen and oxygen isotope compositions (δ¹⁸O and δ²H) at five locations in subtropical northwest Australia over 10 years (2015–2024) to better understand the mechanisms driving precipitation and to identify moisture sources.

Study Configuration

• Spatial Scale: Five locations in subtropical northwest Australia
• Temporal Scale: 10 years (2015–2024)

Methodology and Data

• Models used: Back trajectory analysis
• Data sources: In-situ measurements of rainfall stable hydrogen and oxygen isotope compositions (δ¹⁸O and δ²H)

Main Results

• Precipitation with low δ²H and δ¹⁸O was predominantly observed during months with high rainfall, confirming a significant "amount effect" at most sites.
• δ²H and δ¹⁸O were positively correlated with the stratiform fraction of total precipitation, indicating the importance of sub-cloud evaporation losses during stratiform events.
• The mean sub-cloud evaporated fraction was estimated at approximately 30%.
• Back trajectory analysis revealed that up to 47% of rain moisture during the wet season was recycled from land evapotranspiration.
• Differences between arithmetic and volume-weighted monthly mean stable isotope compositions highlight the seasonal significance of small-volume rainfall events for monthly means.
• A new "cut-off" approach was proposed to eliminate the disproportionate influence of a high proportion of low-volume rainfall on the stable isotope composition of monthly precipitation and Local Meteoric Water Lines.

Contributions

• Provided a decade-long dataset and analysis of rainfall stable isotopes in subtropical northwest Australia, a region sensitive to climate change.
• Quantified the impact of the "amount effect," sub-cloud evaporation, and land evapotranspiration recycling on precipitation isotope compositions in the study region.
• Highlighted the methodological challenge of small-volume rainfall events on monthly mean isotope calculations.
• Proposed a novel "cut-off" approach to improve the accuracy of stable isotope analysis for monthly precipitation and Local Meteoric Water Lines.

Funding

[Information not available in the provided abstract.]

Citation

@article{Wan2026Stable,
  author = {Wan, Chengwei and Dogramaci, Shawan and Gleeson, Jennifer and Hedley, Paul and Grierson, Pauline F. and Gibson, J. J. and Skrzypek, Grzegorz},
  title = {Stable Isotope Record of Precipitation Dynamics in the Semi‐Arid Subtropics},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2026},
  doi = {10.1029/2025jd044431},
  url = {https://doi.org/10.1029/2025jd044431}
}