LIGHTNING FLASH DENSITY FROM THUNDER-DAY RECORDS
The lightning flash density, defined as the number of flashes of a specific type occurring on or over unit area in unit time, is commonly used to describe lightning activity. The lightning flash densities are denoted as Ng, Nc and Nt for cloud-to-ground (CG, or simply ground), intra-cloud (IC, or simply cloud) and total (TF = CG + IC) flashes, respectively, and expressed as a number of flashes per square kilometre per year (km-2 yr-1).
See following page for a comprehensive table of Lightning Flash Density (Ng) for South Africa and Namibia.
SOUTH AFRICAN & NAMIBIA LIGHTNING FLASH DENSITY (Ng).
Expressed as a number of flashes per square kilometre per year (km2 yr-1).