Theoretical and Applied Climatology

, Volume 128, Issue 1–2, pp 421–437 | Cite as

Interannual variability of rainfall characteristics over southwestern Madagascar

  • T. S. M. Randriamahefasoa
  • C. J. C. ReasonEmail author
Original Paper


The interannual variability of daily frequency of rainfall [>1 mm/day] and heavy rainfall [>30 mm/day] is studied for the southwestern region of Madagascar, which is relatively arid compared to the rest of the island. Attention is focused on the summer rainy season from December to March at four stations (Morondava, Ranohira, Toliara and Taolagnaro), whose daily rainfall data covering the period 1970–2000 were obtained from the Madagascar Meteorological Service. El Niño Southern Oscillation (ENSO) was found to have a relatively strong correlation with wet day frequency at each station and, particularly, for Toliara in the extreme southwest. In terms of seasonal rainfall totals, most El Niño (La Niña) summers receive below (above) average amounts. An ENSO connection with heavy rainfall events was less clear. However, for heavy rainfall events, the associated atmospheric circulation displays a Southern Annular Mode-like pattern throughout the hemisphere. For ENSO years and the neutral seasons 1979/80, 1981/82 which had large anomalies in wet day frequency, regional atmospheric circulation patterns consisted of strong anomalies in low-level moisture convergence and uplift over and near southwestern Madagascar that made conditions correspondingly more or less favourable for rainfall. Dry (wet) summers in southern Madagascar were also associated with an equatorward (poleward) displacement of the ITCZ in the region.


Indian Ocean Tropical Cyclone Southern Annular Mode South West Indian Ocean Cloud Band 
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.



The first author is grateful to Carnegie WIO-RISE for the funding of her MSc research from which this manuscript is written.


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Copyright information

© Springer-Verlag Wien 2016

Authors and Affiliations

  • T. S. M. Randriamahefasoa
    • 1
  • C. J. C. Reason
    • 1
    Email author
  1. 1.Deparment of OceanographyUniversity of Cape TownCape TownSouth Africa

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