The Modulating Role of Tropical Atlantic Sea Surface Temperature in Solar-Rainfall Relationships over Lagos, Nigeria

Abstract

The influence of solar activity on tropical rainfall remains uncertain, partly because oceanic variability may modify regional climatic responses. This study investigated the modulating role of Tropical Atlantic sea surface temperature (SST) in solar-rainfall relationships over Lagos, Nigeria, during 1995-2024. Monthly rainfall, F10.7 solar radio flux and NOAA ERSSTv6 data were analysed using interaction regression involving Tropical North Atlantic (TNA), Tropical South Atlantic (TSA), Atlantic Niño (ATL3) and Atlantic Meridional Gradient (AMG) indices. Contemporaneous, 0-6-month lagged and season-specific interactions were evaluated using Newey-West heteroskedasticity- and autocorrelation-consistent inference, joint Wald tests and Benjamini-Hochberg false-discovery-rate correction. The baseline solar-rainfall relationship was insignificant (), while no contemporaneous interaction survived statistical testing. A nominally significant TSA interaction at a two-month lead () became insignificant after correction (q = 0.496). However, seasonal analysis identified a significant joint ATL3 interaction (), with a modest explanatory contribution (). Individual seasonal differences remained insignificant. The study provides preliminary evidence of equatorial Atlantic SST-dependent solar-rainfall associations, demonstrating the importance of seasonal conditioning while highlighting limitations imposed by the relatively short observational record and limited solar-cycle coverage.