In this research we have studied the roles and effects of ENSO atmospheric and oceanic phenomenon on seasonal rainfall fluctuations using multivariate ENSO index (MEI) in Eastern Azerbaijan Province. The results of applying Pearson analysis indicate positive correlation between MEI and precipitation in the stations under study, and among the seasons, the fall season has been showing significant correlation while in other seasons it was not the case. This is an indicative of the increase of autumn precipitation during the occurrence of El Ni?o (positive and warm phase in ENSO phenomenon), and on the contrary the precipitation reduction during the La Ni?a phase (cold and negative phase). Among the stations the maximum correlation of autumn precipitation with the MEI exists in Sarab Station and its minimum is in Tasooj Station. The calculated correlation coefficient rates between precipitation and MEI specify the effects of latitude on the amount of affectation from ENSO, implying that in Eastern Azerbaijan the correlation rates increase from east to the west and from north to south, the maximum of which can be seen in Sarab Station.
Key Words: El Ni?o Southern Oscillation (ENSO), El Ni?o, La Ni?a, Multivariate ENSO Index (MEI), Variability of Season
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