Lagged and Timely Effect of ENSO on Summer Monsoon Precipitation over Sudan across 1991-2020

Monzer Hamadalnel; Ismail Abdalla

doi:10.52981/jfst.vi8.1965

Monzer Hamadalnel
Ismail Abdalla

DOI: https://doi.org/10.52981/jfst.vi8.1965

Keywords: ENSO, Sudan, Summer Monsoon Precipitation

Abstract

This study investigates the timely and lagged effect of El-Nino Southern Oscillation (ENSO) on the summer monsoon rainfall over Sudan. The analysis was carried out based on zero lag (JJAS), one-month lag (May), two-month lag (April), and three-month lag (March). The study analyzed the dominant modes of the seasonal precipitation to identify the leading pattern and its accountability from the total variance. The EOF analysis revealed that the first mode consists of 52.3% of the total variance and 0.92 consistency recorded between the correspondent PC1 against the raw data field of the seasonal precipitation. The summer monsoon precipitation tends to be strongly correlated with ENSO the smaller the analyzed lag with the highest consistency when the lag is zero. A glimpse of the ENSO correlation with summer monsoon precipitation from March to JJAS suggests shifting in the loading's sign starts by positive sign in March before it gradually turns to negative in JJAS with significant values in El-Nino 3.4 region. Similar responses were shown by the inversed effect, where the timely effect surpassed the lagged ones in particular central parts where significant coefficients exhibit.

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