Characterization of hydro-meteorological droughts based on dynamic future scenarios and effective rainfall over Central Malawi

This study explored the most apparent CMIP6 climate scenario experiments to characterize hydro-meteorological droughts in Kasungu Agricultural Development Division (ADD). This study focused on predicting droughts for the years 2020-2029, 2030-2039, and 2040-2049 in light of varying climatic conditions in the central region with an agricultural economy. The future Standard Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index, and Palmer Drought Severity Index. The delta method outperformed other bias correction methods as it indicated lower RMSE (4.67) and MAE (1.08) values, higher R (0.97) values, and positive NSE (0.94) values. The results indicated that moderate (- 1.5 < SPI < - 1.0) and mild droughts (- 1.0 < SPI < 0) are likely to be more common from the mid-term of the 2020-2029 period in the region. All three meteorological droughts indicated remarkably increasing dry conditions in the study area. The findings showed that under SSP1-2.6 and SSP5-8.5, rainfall in the ADD will decrease by 1.8% and 4.3%, respectively, with more extremely dry conditions under SSP5-8.5. Furthermore, the frequency of dry regimes will increase for all stations under SSP5-8.5. The findings have also revealed significant decreases in the effective rainfall and an increase in evapotranspiration that would increase irrigation requirements in the region. According to the findings, the normal rainfall seasons will shift from mid-October to late November, irrigation water requirements will increase, and drought severity will increase in the region. This study, therefore, recommends robust water management plans, crop diversification, and rainwater harvesting plans as disaster risk management plans in mitigating future droughts.