Rakshit et al. (2025) Unseasonal lightning over the Indian Region: Case study integrating observations and model simulations

Identification

• Journal: Atmospheric Research
• Year: 2025
• Date: 2025-10-15
• Authors: Gargi Rakshit, Ashis Mitra, Soumyajyoti Jana
• DOI: 10.1016/j.atmosres.2025.108575

Research Groups

• India Meteorological Department, Ministry of Earth Sciences, Government of India, New Delhi, India
• Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India

Short Summary

This study investigates an unseasonal extreme lightning event in Gujarat, India, on November 26, 2023, by integrating observations and WRF-ELEC model simulations to characterize the synoptic and microphysical drivers. It reveals that the interaction of a cyclonic circulation with Western Disturbances created an atypically moisture-rich environment, leading to enhanced ice and snow concentrations and inverted dipolar charge centers in clouds.

Objective

• To investigate the synoptic weather patterns and microphysical dynamics underlying a rare unseasonal lightning event that occurred in Gujarat, India, on November 26, 2023.

Study Configuration

• Spatial Scale: Gujarat, India, and the northern Arabian Sea.
• Temporal Scale: November 26, 2023.

Methodology and Data

• Models used: Weather Research and Forecasting (WRF)-ELEC model.
• Data sources: Ground-based lightning sensor network, INSAT 3D (Cloud Top Brightness Temperature), ERA5 reanalysis outputs, GPM 2ADPR product (radar reflectivity profile).

Main Results

• An interaction between a cyclonic circulation over the northern Arabian Sea and Western Disturbances created an atypically moisture-rich environment, triggering unseasonal convective activity in Gujarat.
• Observations confirmed convective precipitation devoid of bright band signatures and elevated cloud liquid and ice water content.
• WRF-ELEC simulations showed enhanced ice and snow concentrations in the upper cloud layers, facilitating cloud electrification.
• The simulations indicated the formation of inverted dipolar charge centers, with the negative charge center positioned above the positive one, under non-inductive charging conditions.
• Analysis of space charge structures revealed that graupel particles predominantly acquired positive charges in the mixed-phase layer, driven by elevated cloud liquid water.

Contributions

• Provides a detailed characterization of an unseasonal extreme lightning event by synthesizing both observational data and advanced model simulations.
• Emphasizes the dual roles of synoptic-scale disturbances (Western Disturbances and cyclonic circulation) and microphysical processes in driving such anomalous events.
• Highlights the critical influence of Western Disturbances in modulating convective anomalies in regions typically dry during late November.
• Underscores the need for advancements in forecasting capabilities and understanding of unseasonal weather phenomena to mitigate future risks.

Funding

• Not explicitly mentioned in the provided text.

Citation

@article{Rakshit2025Unseasonal,
  author = {Rakshit, Gargi and Mitra, Ashis and Jana, Soumyajyoti},
  title = {Unseasonal lightning over the Indian Region: Case study integrating observations and model simulations},
  journal = {Atmospheric Research},
  year = {2025},
  doi = {10.1016/j.atmosres.2025.108575},
  url = {https://doi.org/10.1016/j.atmosres.2025.108575}
}