Distribution of thunderstorms
I was interested in the article by Joan Kenworthy on C E P Brooks in September's Weather (pp. 235–237). Whenever I give a talk or lecture on thunderstorms, I refer to the early work of Brooks (1925) in which he estimated that, worldwide, there were 1800 thunderstorms at any one time. This figure has often been quoted since: he based it on reports of thunderstorms, but assumed that the distribution of storms over the sea was the same as over land. Modern techniques are based on worldwide lightning detection and suggest an hourly rate of around 800 thunderstorms, varying with season and time of day.