Spatial and seasonal patterns of flood change across Brazil

Brazil has some of the largest rivers in the world and has the second greatest flood loss potential among the emergent countries. Despite that, flood studies in this area are still scarce. In this paper, we used flood seasonality and trend analysis at the annual and seasonal scales in order to describe flood regimes and changes across the whole of Brazil in the period 1976–2015. We identified a strong seasonality of floods and a well-defined spatio-temporal pattern for flood occurrence. There are positive trends in the frequency and magnitude of floods in the North, South and parts of Southeast Brazil; and negative trends in the North-east and the remainder of Southeast Brazil. Trends in the magnitude (frequency) were predominant in the winter (summer). Overall, floods are becoming more frequent and intense in Brazilian regions characterized by wet conditions, and less frequent and intense in drier regions.