Spatiotemporal analysis of dry spells for support to agriculture adaptation efforts in the Sudano‑Sahelian region of Nigeria

摘要

Change in rainfall pattern is one of the observed and projected impacts of climate change across the Sudano-Sahelianregion of Nigeria. As a consequence, agricultural practices and water resources would highly be impacted. In this study,38-year (1981–2018) daily rainfall data observed over 13 meteorological stations distributed across the Sudano-Sahelianregion of Nigeria were used to investigate the spatial distribution and long-term trend of dry spells. Four dry spell indicesdefined as frequency of dry spell (FDS), total dry spell (TDS), maximum dry spell (MxDS) and mean dry spell (MDS) wereexamined monthly, focusing on the wet season (May–October). The results revealed a positive gradient in TDS, MxDSand MDS from southwest to northeast. In contrast, FDS revealed a negative southwest to northeast gradient. The highestTDS, MxDS and MDS days are found during wet season onset (May–June) and end of season (September–October),while the lowest days are found at the peak of the rainy season (July–August). Furthermore, an analysis of long-termtrend using the nonparametric Mann–Kendall statistical test revealed a prevailing decline in TDS, MxDS and MDS fromMay to October. This could enhance agricultural activities over the region. However, a significant increase in dry spellis evident in Gombe (May–June) and Kaduna (June). This could pose a great threat to agricultural practices over theseregions if it persists.