Spatio-temporal dynamics of Lagos flooding: comparative multi-parameter analysis of 2011 and 2021 events

This study examines changes in flooding characteristics in Lagos, Nigeria, through comparative analysis of major flooding events in July 2011 and July 2021. Satellite data from NASA’s IMERG and MODIS platforms were used to analyse precipitation patterns, aerosol concentrations, and land surface temperatures through spatial autocorrelation and regression analysis. The comparison reveals substantial changes in flood characteristics over this decade of rapid urban development. Maximum flood intensity decreased from 1,053 mm to 760 mm, while flood-prone areas shifted from western urban to eastern coastal regions. Surface temperatures reduced from 43 °C to 39 °C in established urban areas. Notably, the aerosol-precipitation relationship changed from negative spatial correlation (ρ = -0.21) in 2011 to positive correlation (ρ = 0.47) in 2021, suggesting modified atmospheric processes. Spatial clustering patterns weakened (Moran’s I: 0.92 to 0.86), indicating changing spatial organization of flood parameters. Built-up areas increased by 37% with impervious surface coverage expanding from 48 to 68%, while flood duration increased by 5 h despite lower peak intensities. These observed changes occurred alongside regional climate modifications, including a 1 °C increase in sea surface temperatures and 8% rise in atmospheric moisture content. The findings suggest that flood vulnerability in rapidly growing coastal cities may evolve substantially over decadal timescales, requiring adaptive management strategies that can respond to changing urban-climate interactions. While these observations are specific to Lagos, they provide insights that may be relevant for other rapidly developing coastal megacities experiencing similar urbanization and climate pressures.