Spatio-temporal Assessment of Heat Waves in different Climate Zones of Nigeria

Abstract

This study examines spatial and temporal heat wave characteristics in Nigeria using the Köppen climate classification system (KCCS). It analyzes the Heat Wave Duration Index (HWDI) and Heat Wave per Time (HWPT) for six major KCCS: Af (Tropical rainforest climate), Am (Tropical monsoon climate), Aw (Tropical savanna climate), Bsh (Hot semi-arid climate), Bwh (Hot desert climate), and Csh (Cold semi-arid climate). The data from 2010 to 2022 was obtained from the European Center for Medium Range Weather Forecast version-5 Reanalysis (ERA5) data sets. The results reveal distinct variations in HWDI/HWPT values across climate categories. The Af, Am, Aw and Csh classes exhibit positive regression coefficients, indicating a rising trend in HWDI/HWPT per year. In contrast, the Bsh and Bwh classes have negative regression coefficients, suggesting a decreasing trend in HWDI. The monthly distribution of HWDI and HWPT shows varying patterns across climate classes. Higher values of HWDI and HWPT are observed in specific months (especially dry season months), reflecting the seasonal variability of heat waves. The spatial distribution analysis highlights areas with high HWDI/HWPT values, such as Bauchi, Borno, Kano, Jigawa, and Katsina from November to May. The study also investigates the impact of land cover types on heat wave characteristics, with different land cover classes contributing varied percentages of heat wave occurrence, with barelands having the highest heat wave occurrence. The findings emphasize the importance of considering KCCS when assessing heat waves and provide valuable insights for developing targeted adaptation strategies to mitigate the impacts of heat waves in specific regions.