Cao et al. (2025) Increasing Frequency of Very Severe Cyclonic Storms Over the Northern Indian Ocean Driven by Anthropogenic Greenhouse Gas Forcing

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

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-11-18
• Authors: Xi Cao, Renguang Wu, Xianling Jiang, Changgui Lin, Yifeng Dai, Pengfei Wang, Ping Huang, Xiaoqing Lan, Shangfeng Chen, Liang Wu, Zheng Wang, Qihua Li, Xiao Xiao
• DOI: 10.1029/2025gl119299

Research Groups

Not specified in abstract.

Short Summary

This study identifies a significant increasing trend in the frequency of very severe cyclonic storms over the northern Indian Ocean since 1979, attributing this trend primarily to greenhouse gas emissions, with anthropogenic aerosols having a dampening effect.

Objective

• To identify trends in cyclonic storm frequency over the northern Indian Ocean and attribute the underlying causes, particularly focusing on the role of greenhouse gas emissions and anthropogenic aerosols.

Study Configuration

• Spatial Scale: Northern Indian Ocean (NIO).
• Temporal Scale: Since 1979.

Methodology and Data

• Models used: Detection and Attribution Model Intercomparison Project (DAMIP) experiments (specific model names not detailed).
• Data sources: Model output from DAMIP experiments; implied observational/reanalysis data for observed trends.

Main Results

• A significant increasing trend in the frequency of cyclonic storms (maximum sustained winds exceeding 17.5 m/s) over the northern Indian Ocean has been observed since 1979.
• This trend is primarily driven by a pronounced rise in the number of very severe cyclonic storms (maximum sustained wind speed exceeding 32.9 m/s).
• The increased frequency of very severe cyclonic storms is associated with enhanced lower-middle tropospheric relative humidity due to vertical moisture advection.
• Strengthened upward motion, contributing to these conditions, is primarily caused by anomalous positive vorticity advection by mean westerly flows.
• Analysis of DAMIP experiments demonstrates that the mid-level cyclonic circulation trend is predominantly forced by greenhouse gas emissions, while anthropogenic aerosols exert a dampening effect.

Contributions

• Provides robust evidence for an increasing trend in very severe cyclonic storms in the northern Indian Ocean.
• Offers a physical explanation for the observed increase, linking it to atmospheric moisture and circulation changes.
• Quantifies the distinct roles of greenhouse gas emissions (forcing) and anthropogenic aerosols (dampening) in driving the observed cyclonic circulation trends, thereby attributing the changes to specific anthropogenic factors.
• Highlights the escalating risk of stronger cyclones for densely populated coastal nations in the region under continued climate change.

Funding

Not specified in abstract.

Citation

@article{Cao2025Increasing,
  author = {Cao, Xi and Wu, Renguang and Jiang, Xianling and Lin, Changgui and Dai, Yifeng and Wang, Pengfei and Huang, Ping and Lan, Xiaoqing and Chen, Shangfeng and Wu, Liang and Wang, Zheng and Li, Qihua and Xiao, Xiao},
  title = {Increasing Frequency of Very Severe Cyclonic Storms Over the Northern Indian Ocean Driven by Anthropogenic Greenhouse Gas Forcing},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl119299},
  url = {https://doi.org/10.1029/2025gl119299}
}