The movement of precipitation around the Earth has an integral impact on fresh water availability, vegetation, and the
occurrence of natural disasters, and therefore human society at large. In the African Sahel, the rainfall is the limiting factor in
agriculture and the most variable characteristic of climate both spatially and temporally. In light of recent famine concerns, research on
rainfall variability in the Sahel is critical as well as timely. A review of climate and environmental literature provided a perspective
and a set of methodologies upon which the research could build. This research emphasizes the role of the regional and global atmospheric
circulation in governing the variability of Sahel rainfall. It examines the changing spatiotemporal characteristics of the rainfall regime
in the context of the Tropical Easterly Jet (TEJ), the El Nino/Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Tibetan
High. Historical data was obtained from the African rain gauge network, NCEP/NCAR Reanalysis 1, and HadISST version 1.1. The results of
this study show that the relationship between the TEJ and Sahel rainfall is a casual one, with a stronger TEJ enhancing upper-level
divergence to promote broader, more intense vertical ascent. It also showed that diagnostic variables relevant to the general circulation,
such as the maximum ascent within the rainbelt, the northward displacement of the AEJ, and the advection of precipitable water over the
Sahel have a robust positive relationship with the Sahel rainfall anomaly due to the influence of the TEJ. The results also determined
that a significant relationship exists in terms of the high-frequency interannual variability between negative ENSO events and the
strengthening of the TEJ, which would similarly lead to anomalously wet years in the Sahel during a negative ENSO anomaly. This study
posits a new framework for understanding rainfall variability in the Sahel due to its focus on the impacts of the atmospheric circulation.
Furthermore, it can have important applications to understanding and forecasting droughts and floods in the Sahel, improve the modeling of
Sahel climate, and provide a basis for further study of how West Africa and the TEJ fit into the global picture. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment
of the requirements for the degree of Master of Science. / Fall Semester 2016. / November 22, 2016. / Africa, Climate, Jet, Rainfall, Sahel, Tropical / Includes bibliographical references. / Sharon Nicholson, Professor Directing Thesis; Jeffrey Chagnon, Committee Member; Vasubandhu
Misra, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_405594 |
| Contributors | King, Sidney E. (Sidney Earle) (authoraut), Nicholson, Sharon E. (professor directing thesis), Chagnon, Jeffrey M. (committee member), Misra, Vasubandhu, 1970- (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting departmentdgg) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (112 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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