Li et al. (2025) Possible increase of tropical cyclone genesis frequency over the Northwest Pacific induced by the Tambora eruption in 1815

Identification

• Journal: Weather and Climate Extremes
• Year: 2025
• Date: 2025-11-21
• Authors: Yue Li, Yang Yang, Jiuwei Zhao, Kun Wu, Shanshan Liu
• DOI: 10.1016/j.wace.2025.100837

Research Groups

• State Key Laboratory of Climate System Prediction and Risk Management/Institute of Climate and Application Research, Nanjing University of Information Science & Technology (NUIST), China
• College of Ecology and Environment, Joint Innovation Center for Modern Forestry Studies, Nanjing Forestry University, China
• School of Marine Science and Engineering, Nanjing Normal University, China

Short Summary

This study investigates the impact of the 1815 Tambora and 1991 Pinatubo tropical volcanic eruptions on tropical cyclone (TC) activity in the western North Pacific (WNP). Using high-resolution simulations and reanalysis data, the authors find that both eruptions significantly increased WNP TC genesis frequency and track density, primarily driven by dynamic factors like equatorial westerly wind anomalies despite general global cooling.

Objective

• To investigate the effects of the 1815 Tambora eruption and the 1991 Pinatubo eruption on tropical cyclone genesis frequency (TCGF) and track density (TCTD) in the western North Pacific (WNP).
• To unravel the underlying dynamic and thermodynamic mechanisms controlling the circulation environment favorable for TC genesis over the WNP following these tropical volcanic eruptions.

Study Configuration

• Spatial Scale: Western North Pacific (WNP), within a tropical belt domain from 5°S to 50°N with 5° buffer zones. Global (90°S-90°N) and tropical (60°S-60°N) averages for skin temperature anomalies.
• Temporal Scale:
  • Preindustrial period: 1815 (Tambora eruption) and 1816–1844 (climatological reference).
  • Present-day period: 1991 (Pinatubo eruption) and 1984–2013 (climatological reference).
  • TC season: June to November.

Methodology and Data

• Models used:
  • Regional Climate Model (RCM) with 0.25° horizontal resolution and 28 vertical levels, incorporating a modified Tiedtke convective parameterization scheme and a Mellor and Yamada boundary scheme, with the dynamic core from the high-resolution TC Model (Wang, 2001).
  • Emanuel and Nolan Genesis Potential Index (ENGPI).
  • Dynamic Genesis Potential Index (DGPI).
• Data sources:
  • Observational TC records: Joint Typhoon Warning Center (JTWC) / International Best Track Archive for Climate Stewardship (IBTrACS) (1984–2013).
  • Reanalysis data:
    • NOAA-20CRv3 (Twentieth Century Reanalysis version 3) (1805–2014) for 6-hourly atmospheric data and daily sea surface temperature (SST) data, used for RCM initial and boundary conditions.
    • NCEP/NCAR Reanalysis version I (NCEP/NCAR v1) for verification (1984–2013).

Main Results

• Both the 1815 Tambora and 1991 Pinatubo tropical volcanic eruptions (TVEs) led to significant increases in Tropical Cyclone Genesis Frequency (TCGF) and Tropical Cyclone Track Density (TCTD) over the Western North Pacific (WNP).
• The simulated WNP TCGF in 1815 was, on average, 5.06 higher than the 1816–1844 climatological mean (31.4 vs 26.35), a statistically significant increase (p < 0.05).
• The simulated WNP TCGF in 1991 was about 1.6 higher than the 1984–2013 climatological mean (23.9 vs 22.3). Observed WNP TCGF in 1991 was 26, which is 3.8 higher than the climatological mean of 22.2.
• The increase in WNP TCGF and TCTD was consistently identified over the southeastern quadrant of the WNP basin for both eruptions.
• The Tambora eruption triggered equatorial central Pacific warming, which induced tropical westerly wind anomalies in the WNP.
• Dynamic factors, including low-level vorticity, enhanced upward motion, and locally reduced vertical wind shear, were the dominant contributors to the increased TC genesis, overcoming generally unfavorable thermodynamic conditions (decreased relative humidity and potential intensity due to global cooling).
• The climatological WNP TCGF in the Preindustrial run (1816–1844) was 4.05 higher than in the Present-day run (1984–2013), suggesting that global warming leads to a decrease in WNP TCGF.

Contributions

• This study provides the first systematic evaluation of the Tambora eruption's impact on WNP TCGF using high-resolution dynamical downscaling, validated by comparison with the well-documented Pinatubo eruption.
• It elucidates the dominant role of dynamic factors (e.g., equatorial westerly wind anomalies, low-level vorticity, vertical motion) in enhancing WNP TC genesis following tropical volcanic eruptions, even when thermodynamic conditions are unfavorable.
• The findings suggest that the cooling effect of TVEs can be considered a transient analog of global warming, providing valuable insights into future TC variability under changing climatic conditions, particularly highlighting an inverse relationship between global temperature and WNP TCGF.
• The research underscores the importance of incorporating volcanic forcing into future climate projections and hazard risk assessments due to its potential to alter regional atmospheric circulation and extreme weather events.

Funding

Not explicitly stated in the provided text.

Citation

@article{Li2025Possible,
  author = {Li, Yue and Yang, Yang and Zhang, Leying and Zhao, Jiuwei and Wu, Kun and Liu, Shanshan},
  title = {Possible increase of tropical cyclone genesis frequency over the Northwest Pacific induced by the Tambora eruption in 1815},
  journal = {Weather and Climate Extremes},
  year = {2025},
  doi = {10.1016/j.wace.2025.100837},
  url = {https://doi.org/10.1016/j.wace.2025.100837}
}