Analysis Method and Three-Dimensional Distribution Characteristics of Cloud-to-Ground Lightning Under Mesoscale Topography

Mesoscale topography (ranging from approximately 100 meters to 5 kilometers in scale) has a significant impact on the spatial distribution of lightning activity, but the quantitative analysis methods for this phenomenon are still not well-developed. This paper proposes a mesoscale analysis method for cloud-to-ground lightning by integrating Gaussian fitting with topographic variation features, and reveals the three-dimensional distribution characteristics of lightning activity under typical mesoscale topography. By analyzing nearly a decade-long lightning location data from a mountainous region, this study reveals a strong positive correlation between cloud-to-ground lightning flash density and elevation under typical mesoscale topography, and proposes a mesoscale terrain boundary delineation method based on the full-range mean approach. The results indicate that in complex mesoscale terrain, the lightning ground flash density in areas with steep slopes (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt;25^{\circ}$</tex>) and high altitudes (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt;700$</tex> meters) is approximately <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$15 \%-30 \%$</tex> higher that that in surrounding areas. This paper provides an important basic data analysis method for studying the distribution of lightning ground flash density and offers valuable insights for lightning protection design in industries such as power systems and electrified railways.