Three tropical "chimney" centers (Africa, the Americas, Asia)

Global lightning activity is not distributed evenly. It is concentrated in three tropical regions, often called "chimneys" after the powerful updrafts of deep convection:

• Africa — the strongest of the three centers,
• South and Central America (especially the Amazon basin),
• Southeast Asia / Maritime Continent (the Indonesian archipelago).

Each center has its diurnal maximum, tied to the afternoon heating of the land. Expressed in Universal Time (UT), the maxima occur approximately as follows: Asia around 08-10 UT, Africa around 14-16 UT and the Americas around 20-22 UT Williams 1992Satori 2024.

This gradual "passing of the baton" between continents creates the characteristic diurnal curve of the SR. Because the individual centers lie at different geographic longitudes, their alternation can be distinguished in the SR signal and used to reconstruct where and when lightning activity is most intense Satori 2024.