Maximum cloud-to-ground lightning flash densities observed by lightning location systems in the tropical region: A review

A comprehensive review of maximum cloud-to-ground (CG) lightning flash densities observed in the tropical region by different Lightning Location Systems (LLS) is presented. From the observed values, absolute maximum values for a spatial resolution of 1 km × 1 km are estimated, using an empirical curve relating flash density and resolution and correcting the data for differences in the detection efficiency and in the intracloud (IC) contamination of the different LLS. Maximum CG lightning flash densities are compared with total lightning observations by satellite in the same regions, for a spatial resolution of approximately 55 km × 55 km, to infer IC to CG ratios (IC/CG). It was found that absolute maximum CG lightning flash densities in the tropical region vary from 19 to 65 flashes km− 2 year− 1 and IC/CG ratios from 3.9 to 12.6. Absolute maximum CG lightning flash densities and the IC/CG ratios in the tropical region are then compared with similar values in the temperate region. Only the regions corresponding to the highest maximum CG lightning flash densities observed by LLS for each continent in the temperate region are considered. The comparison suggests that higher absolute maximum CG lightning flash densities occur in the tropical region and similar IC/CG ratios occur in both regions, with the exception of Colombia and Venezuela, where this ratio seems to be higher than in any other regions.