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Temporal variability and persistence of dry spells during the rainy season at Lubumbashi (Congo-Kinshasa) Volume 10, issue 1, Mars 1999

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  • Page(s) : 45
  • Published in: 1999

Temporal variations in dry spells during the rainy season at Lubumbashi during the 20th century can be characterized by the following three periods: – the first period is marked by the number of dry days higher than the mean of the series. This period started before 1921 and ended around 1950 ; – the second period involved a reduction of around 23.5% in the number of dry days. It ended about 1980 ; – the current period in which there has been an increase in the number of dry days, i.e. there has been an increase of 36.2% over the last 15 years. In terms of persistence, these dry spells can remain constant for 4 consecutive days, and this pattern is best expressed logarithmically. The variability and persistence of dry spells depends on the frequency of the Mascareigne trade winds in the lower troposphere during the rainy season. This frequency is affected by variations in the force and latitudinal movement of the Mascareigne anticyclone during relatively short periods.