Anomalies Of Isobaric Fields In The Southwestern Indian Ocean During El Nino Climatic Events

Abstract

Fanja Tahina RALINIRINA

The el Nino climate event has produced upheavals in the global climate. Among many others is the prolonged drought in the Sahel. In fact, these upheavals are the direct consequences of changes in the centers of action. Therefore, we are interested in knowing their configuration in the South-West Indian Ocean basin, SWOI, both on the ground and at altitude during the two seasons, summer and winter in the southern hemisphere. It has been observed that there are negative pressure anomalies in the western part of the SWOI and positive ones in its eastern part; moreover the geopotential levels 700hPa and 500hPa include positive anomalies in the north and negative anomalies in the south. These mid-altitude results continue at high altitude, with the tropopause experiencing low anomalies on the equator side and high anomalies on the south pole side. As a result on the other hand, the southern winter experiences more moisture than normal. The significance of the images showing isobaric field anomalies was tested by the Student t-test.

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