Opposite Effects of ENSO on the Rainfall over the Northern and Equatorial Great Horn of Africa and Possible Causes
Joint Authors
Source
Issue
Vol. 2020, Issue 2020 (31 Dec. 2020), pp.1-16, 16 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2020-09-03
Country of Publication
Egypt
No. of Pages
16
Main Subjects
Abstract EN
In this study, we explore the possible mechanism of opposite ENSO effects on summer rainfall in the JJAS region (northern GHA) and autumn rainfall in the OND region (equatorial GHA).
The two regions are identified based on the spatial distribution of high seasonal fractions of annual rainfall for the period 1979–2016.
The summer rainfall over the JJAS region is negatively correlated with ENSO.
It is because the warm Niño3.4 SST triggers zonal wave one pattern in tropics and forces upper-level westerly anomaly and the low-level easterly anomaly over tropical Africa.
Thus, the weakened upper-level Tropical Easterly Jet (TEJ) and the low-level westerly over the JJAS region result in deficient rainfall during JJAS over the northern GHA.
For the autumn rainfall variability over the equatorial GHA, IOD is a pivotal factor.
But, autumn rainfall anomalies are far greater in ENSO and IOD coexisting years than those in IOD alone years.
In other words, ENSO has a significant impact on the autumn rainfall over the equatorial GHA by means of IOD.
It is because the warming SST, which is fully developed over western Indian Ocean (IO) in autumn of ENSO developing year, causes low-level convergence over the equatorial GHA and enhances upper-level easterly over tropical Africa.
Those conditions are favorable for abundant rainfall over the equatorial GHA in autumn.
American Psychological Association (APA)
Kiflie, K. Abebe& Tao, Li. 2020. Opposite Effects of ENSO on the Rainfall over the Northern and Equatorial Great Horn of Africa and Possible Causes. Advances in Meteorology،Vol. 2020, no. 2020, pp.1-16.
https://search.emarefa.net/detail/BIM-1127222
Modern Language Association (MLA)
Kiflie, K. Abebe& Tao, Li. Opposite Effects of ENSO on the Rainfall over the Northern and Equatorial Great Horn of Africa and Possible Causes. Advances in Meteorology No. 2020 (2020), pp.1-16.
https://search.emarefa.net/detail/BIM-1127222
American Medical Association (AMA)
Kiflie, K. Abebe& Tao, Li. Opposite Effects of ENSO on the Rainfall over the Northern and Equatorial Great Horn of Africa and Possible Causes. Advances in Meteorology. 2020. Vol. 2020, no. 2020, pp.1-16.
https://search.emarefa.net/detail/BIM-1127222
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1127222