The separate contributions of line squalls, thunderstorms and the monsoon to the total rainfall in nigeria

Abstract Using thunderstorm and rainfall information from five Nigerian stations for a five year period, the separate contributions of line squalls, thunderstorms and ordinary monsoons to the total rainfall and their variations with latitude are investigated. Total and thunderstorm rainfall decreases with increasing latitude but monsoon precipitation decreases exponentially while line squall rainfall is at a maximum around 9°N. Rainfall from thunderstorms shows a single annual peak in July/August at stations north of about 8°N whereas line squall precipitation exhibits a double maximum for all stations south of 12°N. It is also shown that, in the mean, line squalls are the most important rain producing systems, giving 47‐6 per cent of the mean total annual precipitation compared with 39 per cent and 13‐4 per cent from thunderstorms and ordinary monsoon rain, respectively.