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Climatic Change

, Volume 126, Issue 1–2, pp 263–272 | Cite as

Satellite-based rainfall data reveal a recent drying trend in central equatorial Africa

  • Jeremy E. DiemEmail author
  • Sadie J. Ryan
  • Joel Hartter
  • Michael W. Palace
Letter

Abstract

West-central Uganda, a biodiversity hotspot on the eastern edge of central equatorial Africa (CEA), is a region coping with balancing food security needs of a rapidly growing human population dependent on subsistence agriculture with the conservation of critically endangered species. Documenting and understanding rainfall trends is thus of critical importance in west-central Uganda, but sparse information exists on rainfall trends in CEA during the past several decades. The recently created African Rainfall Climatology version 2 (ARC2) dataset has been shown to perform satisfactorily at identifying rainfall days and estimating seasonal rainfall totals in west-central Uganda. Therefore, we use ARC2 data to assess rainfall trends in west-central Uganda and other parts of equatorial Africa from 1983–2012. The core variables examined were three-month rainfall variables for west-central Uganda, and annual rainfall variables and seasonal rainfall totals for a transect that extended from northwestern Democratic Republic of the Congo to southern Somalia. Significant decreases in rainfall in west-central Uganda occurred for multiple three-month periods centered on boreal summer, and rainfall associated with the two growing seasons decreased by 20 % from 1983–2012. The drying trend in west-central Uganda extended westward into the Congo rainforest. Rainfall in CEA was significantly correlated with the Atlantic Multidecadal Oscillation (AMO) at the annual scale and during boreal summer and autumn. Two other possible causes of the decreasing rainfall in CEA besides North Atlantic Ocean sea-surface temperatures (e.g., AMO), are the warming of the Indian Ocean and increasing concentrations of carbonaceous aerosols over tropical Africa from biomass burning.

Keywords

Indian Ocean Dipole Boreal Summer Rainfall Trend Carbonaceous Aerosol Atlantic Multidecadal Oscillation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

This research was supported by a National Science Foundation Coupled Natural-Human Systems Exploratory grant (NSF-EX: 1114977). We are grateful to the three anonymous reviewers for their comments that greatly improved the article.

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Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Jeremy E. Diem
    • 1
    Email author
  • Sadie J. Ryan
    • 2
    • 3
  • Joel Hartter
    • 4
  • Michael W. Palace
    • 5
  1. 1.Department of GeosciencesGeorgia State UniversityAtlantaUSA
  2. 2.Department of GeographyUniversity of FloridaGainesvilleUSA
  3. 3.Emerging Pathogens InstituteUniversity of FloridaGainesvilleUSA
  4. 4.Environmental Studies ProgramUniversity of ColoradoBoulderUSA
  5. 5.Earth Systems Research Center, Institute for the Study of Earth, Oceans, and SpaceUniversity of New HampshireDurhamUSA

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