TITLE:
Influence of the Quasi-Biennial Oscillation on Summer Precipitation in Eastern and Southern Africa
AUTHORS:
Madundo Albert Marco, Rongjun Wang, Dorah John, Mohamed Bakar, Lipiki Elias, Mhenzi Fredy, Aminu Dalhatu Datti
KEYWORDS:
The QBO, Precipitation Variability, Eastern and Southern Africa, Circulation Analysis
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.13 No.11,
November
4,
2025
ABSTRACT: The Quasi-Biennial Oscillation (QBO) is a vital mode of stratospheric variability with significant influence on tropical and subtropical climate systems. However, its influence on precipitation variability across Eastern and Southern Africa remains insufficiently understood. This study examines the impact of the QBO on summer precipitation and associated circulation anomalies over Eastern and Southern Africa from 1979 to 2021. Using ERA5 and NOAA reanalysis datasets, we applied composite and correlation analyses to assess precipitation responses to westerly (WQBO) and easterly (EQBO) phases. Results show a dipole-like pattern, with WQBO linked to enhanced precipitation in both Eastern and Southern Africa, while EQBO is associated with reduced precipitation. Circulation analysis reveals that WQBO phases promote upper-level divergence, low-level moisture inflow, and vertical ascent, whereas EQBO phases enhance subsidence and upper-level convergence. These findings highlight the QBO role in modulating precipitation through stratosphere-troposphere coupling and its interaction with regional circulation patterns. The quasi-periodic nature of QBO offers substantial potential for enhancing seasonal precipitation predictions when integrated with other regional circulations, such as the Botswana High and the Angola Low.