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Sensitivity Analysis of the WRF Model in Simulating the Lightning Potential Index (LPI) in Tehran

Document Type : Original Article

Authors
Sakineh Khansalari 1
Maryam Gharaylou 2
1 Research Institute of Meteorology and Atmospheric Science, Tehran, Iran
2 Space Physics, Institute of Geophysics, University of Tehran, Tehran, Iran
10.30467/nivar.2025.531870.1342
Abstract
This study investigates the sensitivity of the Weather Research and Forecasting (WRF) model in simulating lightning activity, with a focus on the Lightning Potential Index (LPI), a commonly used parameter for estimating lightning occurrence. The research was conducted over the Tehran region, where ten well-documented lightning events from 2015 to 2022 were selected based on data from the Earth Networks Total Lightning Network (ENTLN), which provides comprehensive detection of total lightning (both intra-cloud and cloud-to-ground). To evaluate the influence of microphysical parameterizations on lightning simulation, seven distinct model configurations were implemented, including three single-moment and four double-moment cloud microphysics schemes. These configurations were chosen based on their usage in previous studies and their theoretical capabilities in resolving cloud microstructure and electrification processes. The LPI was computed for each simulation to represent lightning potential on a 10-minute temporal resolution. Model outputs were compared against ENTLN observations through both graphical and statistical methods. Boxplot analyses were used to assess the distribution, variability, and median values of simulated LPI across different days and configurations. In addition, four quantitative verification metrics were calculated for each case: Probability of Detection (POD), Success Ratio (SR), Bias, and Critical Success Index (CSI). These metrics enabled an objective assessment of how well each microphysics scheme captured the observed lightning events. The results indicate a substantial sensitivity of LPI simulations to the choice of microphysics scheme. No single configuration consistently outperformed the others across all events. However, Configuration 2, which employs the Goddard microphysics scheme, demonstrated relatively superior performance in several case studies, offering a better balance between detection rate and false alarms. The findings suggest that the microphysical treatment of hydrometeors and charge separation processes can significantly influence lightning prediction skill. Overall, this study highlights the necessity of carefully selecting microphysics schemes tailored to local convective environments. Moreover, it underscores the value of ensemble-based approaches using multiple model configurations to better capture the uncertainty inherent in lightning forecasting.
Keywords
Lightning
WRF model
LPI index
Microphysics
Sensitivity analysis
Tehran
Subjects
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Nivar
Volume 49, 130-131 - Serial Number 130
October 2025
Pages 137-159

  • Receive Date 30 June 2025
  • Revise Date 22 July 2025
  • Accept Date 27 July 2025
  • Publish Date 23 September 2025