Li et al. (2025) Evaluation of the effectiveness of the large turbulent eddies parameterization in typhoon for typhoon intensity forecasting

Identification

• Journal: Atmospheric Research
• Year: 2025
• Date: 2025-12-10
• Authors: Xin Li, Ying Li, Zhiqiu Gao
• DOI: 10.1016/j.atmosres.2025.108690

Research Groups

• Climate and Weather Disasters Collaborative Innovation Center, Key Laboratory for Aerosol-Cloud -Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing, China
• State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

Short Summary

This study evaluates the effectiveness of a large turbulent eddies (LEs) parameterization (LP scheme) in the WRF model for typhoon intensity forecasting, revealing that the original scheme can disrupt inflow and lead to poor simulations, but modifications like adding divergence and Richardson number thresholds significantly improve accuracy for Super Typhoon Lekima (2019).

Objective

• To further investigate the rationality and effectiveness of the Li and Pu (2021) large turbulent eddies (LEs) parameterization (LP scheme) in typhoon intensity forecasting using the WRF model.
• To examine the critical processes within the LP scheme and propose modifications for improved typhoon simulation.

Study Configuration

• Spatial Scale: Typhoon planetary boundary layer, focusing on specific typhoons (Lekima 2019, Hato 2017, Maria 2018).
• Temporal Scale: Simulations of specific typhoon events, including 79 sensitivity simulations for Super Typhoon Lekima (2019).

Methodology and Data

• Models used: WRF model (Weather Research and Forecasting model).
• Data sources: Sensitivity simulations, best-track data (for comparison), and implied observations (for "as observed" and "previous observation verified").

Main Results

• The original LP scheme leads to LEs covering more of the inflow region due to weak convergence flow, causing strong negative momentum flux that disrupts inflow structure and results in poor typhoon simulations (e.g., lower sea-level pressure than best-track due to enhanced wind speed).
• Adding a moderate divergence and Richardson number (Ri) threshold (LED03-RI30) suppresses excessive vertical mixing in the inflow region, ensuring typhoon intensification and leading to an intense typhoon as observed for Lekima (2019).
• Reducing the scale factor of LE intensity in the LP scheme also results in a stronger typhoon but delays its intensification.
• The calculation of Hm (the height of maximum LE intensity) could be improved by using planetary boundary layer height, fixed height, or height scaling.
• Validation simulations for Typhoon Hato (2017) and Maria (2018) showed a weak effect of the LP scheme, attributed to weaker vertical velocity gradients in these typhoons compared to Lekima, suggesting the importance of vertical structure in LE parameterization.

Contributions

• Provides a comprehensive evaluation of the Li and Pu (2021) LE parameterization (LP scheme) within the WRF model for typhoon intensity forecasting.
• Identifies critical flaws in the original LP scheme, specifically concerning excessive vertical mixing and its impact on inflow structure.
• Proposes and validates specific modifications (divergence and Richardson number thresholds) to the LP scheme that significantly improve typhoon intensity simulation for Super Typhoon Lekima (2019).
• Emphasizes the necessity of incorporating the vertical structure and vertical velocity gradients into LE parameterization for accurate typhoon simulations across different events.

Funding

• Not explicitly listed in the provided text.

Citation

@article{Li2025Evaluation,
  author = {Li, Xin and Li, Ying and Gao, Zhiqiu},
  title = {Evaluation of the effectiveness of the large turbulent eddies parameterization in typhoon for typhoon intensity forecasting},
  journal = {Atmospheric Research},
  year = {2025},
  doi = {10.1016/j.atmosres.2025.108690},
  url = {https://doi.org/10.1016/j.atmosres.2025.108690}
}