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An investigation into the role of synoptic conditions on Central African precipitation variability

  • Research Article - Atmospheric & Space Sciences
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Abstract

The synoptic precipitation variability over Central Africa (CA) in the March-to-May (MAM) and September-to-November (SON) seasons is investigated in this study. The composite analysis is used to highlight the evolution of synoptic precipitation, related convection, and dynamic fields. Composite analysis findings show that synoptic precipitation anomalies increase/fade with an increase/decrease in convection, with the largest amplitude over 5° S–10° N and 2.5–20° E in MAM and 5° N–7.5° N and 5–15° E in SON. Precipitation anomalies and convection associated with the synoptic variability progress eastward preceded (followed) by eastward (westward) low-level wind. This synoptic sequence is associated with a downward motion and an inflow, indicating the storm’s presence, which contributes significantly to precipitation initiation over CA. The empirical orthogonal function for precipitation during the SON season is lower than that observed during the MAM season in the context of the size and spatial pattern. During these precipitation occurrences, the zonal moisture component contributes the most to the moisture initiation over the region. The findings of this study show that the observed convergence/divergence position remains unchanged in intensity irrespective of the positive/negative precipitation events. Overall, the synoptic-scale conditions in MAM contribute around 58% of the total variability in precipitation.

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Availability of data and material

The datasets supporting the conclusions of this article are available in the following website: GPCP data, NCEP and OLR were obtained from (http://www.esrl.noaa.gov); ERA interim data were obtained from the ECMWF (http://www.ecmwf.int/).

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Acknowledgements

The authors would like to thank NOAA (http://www.cdc.noaa.gov) for GPCP, OLR and NCEP datasets. This research work is partly supported by the DST CoE in Climate Modeling. The authors are thankful to the ECMWF for providing Era-Interim products available. The authors are also grateful to the two  anonymous reviewers for their constructive and helpful suggestions which  contributed to improve the manuscript.

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No funding was received to assist with the preparation of this manuscript.

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Authors and Affiliations

  1. Department of Physics Faculty of Science, University of Yaounde I, P.O. BOX 812, Yaounde, Cameroon

    Sinclaire Zebaze, A. J. Komkoua Mbienda, Wilfried Pokam Mba & Derbetini Appolinaire Vondou

  2. Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India

    Raju Pathak, Popat Salunke, Abhishek Anand & Saroj Kanta Mishra

  3. Department of Physics, Faculty of Science, University of Dschang, Dschang, Cameroon

    A. J. Komkoua Mbienda

  4. Higher Teacher Training College, University of Yaounde I, Yaounde, Cameroon

    Wilfried Pokam Mba

  5. Department of Physics, Faculty of Science, University of Douala, Douala, Cameroon

    André Lenouo

  6. Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia

    Raju Pathak

  7. Earth System Physics Section, Abdus Salam ICTP, Trieste, Italy

    A. J. Komkoua Mbienda

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  1. Sinclaire Zebaze
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  2. Raju Pathak
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Correspondence to Sinclaire Zebaze.

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Edited by Prof. Ioannis Pytharoulis (ASSOCIATE EDITOR) / Prof. Theodore Karacostas (CO-EDITOR-IN-CHIEF).

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Zebaze, S., Pathak, R., Komkoua Mbienda, A.J. et al. An investigation into the role of synoptic conditions on Central African precipitation variability. Acta Geophys. 70, 943–962 (2022). https://doi.org/10.1007/s11600-022-00754-2

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