Zhang et al. (2025) Asymmetry of Tropical Pacific Precipitation Responses to El Niño and La Niña in a Changing CO ₂ Pathway

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

Identification

• Journal: International Journal of Climatology
• Year: 2025
• Date: 2025-10-13
• Authors: Weichen Tao, Ping Huang, Kaiming Hu, Ya Wang, Haosu Tang, Suqin Zhang
• DOI: 10.1002/joc.70155

Research Groups

Not explicitly mentioned in the abstract.

Short Summary

This study constructs an idealised scenario of symmetrical CO2 ramp-up and ramp-down phases to analyse changes in the asymmetric precipitation response to El Niño (EN) and La Niña (LN). It finds that during the CO2 ramp-down phase, both EN and LN precipitation anomalies shift eastward and southward compared to the ramp-up phase, with EN shifts being more pronounced, primarily driven by circulation changes and an EN-like climatological sea surface temperature warming pattern.

Objective

• To analyse the changes in asymmetric precipitation response to El Niño (EN) and La Niña (LN) in the tropical Pacific under an idealised scenario of symmetrical CO2 ramp-up (RU) and ramp-down (RD) phases.

Study Configuration

• Spatial Scale: Tropical Pacific
• Temporal Scale: Idealised CO2 ramp-up and ramp-down climate change scenarios.

Methodology and Data

• Models used: Implied climate model simulations for an idealised CO2 ramp-up/ramp-down scenario; specific model not named.
• Data sources: Model-generated data including precipitation anomalies, sea surface temperature (SST) anomalies, and circulation anomalies from idealised CO2 ramp-up/ramp-down simulations.

Main Results

• During the CO2 ramp-down phase, tropical Pacific precipitation anomalies for both EN and LN shift more eastward and southward compared to the ramp-up phase.
• These shifts are more pronounced in EN than in LN.
• The structural changes in precipitation anomalies are primarily driven by the dynamic component associated with changes in atmospheric circulation anomalies.
• These circulation-driven changes cannot be explained by variations in sea surface temperature (SST) anomalies alone.
• The spatial pattern of climatological SST changes between the CO2 ramp-down and ramp-up phases exhibits an EN-like warming structure, particularly extending southward.
• This climatological warming enhances low-level moisture and weakens atmospheric stability in the region.
• Consequently, precipitation during EN responds more strongly to SST anomalies in this region, leading to its more pronounced eastward and southward shifts.
• La Niña partially offsets the impact of the climatological warming pattern, resulting in less pronounced shifts and contributing to the structural changes in the EN-LN asymmetry of precipitation anomalies.

Contributions

• Provides a novel analysis of the changes in asymmetric precipitation response to EN and LN under symmetrical CO2 ramp-up and ramp-down climate change scenarios.
• Identifies that circulation changes, rather than direct SST anomalies, are the primary drivers of the observed shifts in precipitation anomalies.
• Highlights the role of an EN-like climatological SST warming pattern during CO2 ramp-down in enhancing low-level moisture and weakening atmospheric stability, differentially impacting EN and LN precipitation responses.
• Explains the mechanism behind the more pronounced eastward and southward shifts in EN precipitation anomalies compared to LN during CO2 ramp-down.

Funding

Not mentioned in the abstract.

Citation

@article{Zhang2025Asymmetry,
  author = {Zhang, Wen and Tao, Weichen and Huang, Gang and Huang, Ping and Hu, Kaiming and Wang, Ya and Tang, Haosu and Zhang, Suqin},
  title = {Asymmetry of Tropical Pacific Precipitation Responses to El Niño and La Niña in a Changing <scp> CO <sub>2</sub> </scp> Pathway},
  journal = {International Journal of Climatology},
  year = {2025},
  doi = {10.1002/joc.70155},
  url = {https://doi.org/10.1002/joc.70155}
}