STUDY OF THE EVOLUTION OF THE RAINFALL EXTREMES AND TEMPERATURE EXTREMES IN DAVO RIVER BASIN (SOUTH-WESTERN OF COTE D’IVOIRE) FROM SOME INDICES OF THE SOFTWARE RCLIMDEX

Davo river basin, located at the western-south of Cote d’Ivoire, covers a zone whose the main economic activity is based on agriculture. However, the crop yields of this agriculture dependent on the climate, is influenced by the variation and the climate change. The objective of this work is to study the evolution of the rainfall extremes and temperatures extremes on three synoptic rainfall stations (stations of Daloa, Gagnoa and Sassandra) in Davo river basin. The calculation of the rainfall indices and temperatures indices was performed with the software RclimDex. This study experienced, at the stations of Daloa and Gagnoa, an increase of seven (6) rainfall indices calculated on a total of ten (7). Namely, those indices are: the maximum rainfall of one day height (Rx1day), the days very rainy (R95), the extremely rainy days (R99p) and consecutive wet days (CWD). One of the indices in rise at Daloa relates to the consecutive dry days (CDD) while at Gagnoa it is the maximum total rainfall of 5 days (Rx5day).While the total annual rainfall (PRCPTOT) declined at Daloa and Sassandra but stationary at Gagnoa. Concerning the temperature indices, the diurnal thermal range (DTR) and the warm sequence duration indicator (WSDI) also experienced an increase at the three studied stations while the cool sequence duration indicator is declining at these same stations. Generally, Davo river basin is experiencing a decline in rainfall and therefore an increase in the dry spells during the rainy seasons.