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<p>The processes underlying the anomalous intense rainfall recorded over western equatorial Africa during the September–October-November (SON) season of 2023, are investigated using heat balance, wet enthalpy and potential vorticity anomalies. Diagnosis of the heat balance reveals that diabatic and adiabatic heating advection induced by vertical velocity anomalies were the dominant contributors, especially in the middle and upper troposphere. In contrast, the meridional temperature advection induced by temperature anomalies, zonal temperature advection driven by zonal wind anomalies, and adiabatic heating from potential temperature anomalies were weak throughout the tropospheric column. Additionally, the SON 2023 season was characterised by increased atmospheric specific humidity over western equatorial Africa. Analysis of enthalpy advection indicated that wet enthalpy anomalies transported by the mean zonal wind largely contributed to vertical motion instability, especially in the middle troposphere. The decomposition of moist enthalpy into dry enthalpy and latent heat revealed that the zonal advection of latent heat anomalies around 750&#xa0;hPa was notably stronger than that of dry enthalpy anomalies during this period. Diagnosing potential vorticity anomalies demonstrated that vertical shear influenced updrafts over western equatorial Africa during the anomalous rainfall period, driven by strong positive advection in the zonal component of potential vorticity anomalies. These findings underscore the importance of considering thermodynamic effects in anticipating extreme events. Understanding the associated processes can enhance forecast accuracy, improve projections, and strengthen the region’s capacity to safeguard its population against such extreme weather events.</p>

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Analysis of air temperature anomalies during abnormal rainfall events in Western Central Africa from September to November 2023

  • 期刊论文

  • 发表日期：

    2025年5月7日

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  • Brice C. Tchana,
  • Zéphirin Y. Djomou,
  • Kevin Kenfack,
  • Alain T. Tamoffo,
  • Fernand L. Mouassom,
  • Lucie A. Djiotang Tchotchou,
  • Derbetini A. Vondou,
  • César B. Mbane

摘要

The processes underlying the anomalous intense rainfall recorded over western equatorial Africa during the September–October-November (SON) season of 2023, are investigated using heat balance, wet enthalpy and potential vorticity anomalies. Diagnosis of the heat balance reveals that diabatic and adiabatic heating advection induced by vertical velocity anomalies were the dominant contributors, especially in the middle and upper troposphere. In contrast, the meridional temperature advection induced by temperature anomalies, zonal temperature advection driven by zonal wind anomalies, and adiabatic heating from potential temperature anomalies were weak throughout the tropospheric column. Additionally, the SON 2023 season was characterised by increased atmospheric specific humidity over western equatorial Africa. Analysis of enthalpy advection indicated that wet enthalpy anomalies transported by the mean zonal wind largely contributed to vertical motion instability, especially in the middle troposphere. The decomposition of moist enthalpy into dry enthalpy and latent heat revealed that the zonal advection of latent heat anomalies around 750 hPa was notably stronger than that of dry enthalpy anomalies during this period. Diagnosing potential vorticity anomalies demonstrated that vertical shear influenced updrafts over western equatorial Africa during the anomalous rainfall period, driven by strong positive advection in the zonal component of potential vorticity anomalies. These findings underscore the importance of considering thermodynamic effects in anticipating extreme events. Understanding the associated processes can enhance forecast accuracy, improve projections, and strengthen the region’s capacity to safeguard its population against such extreme weather events.