East African "shorts rains" variability has long been a subject of interest both for its complexity and its sometimes dire human impacts. Four large-scale factors are thought to
influence the shorts rains: Niño 3.4, the IOZM, and the surface and upper-level zonal winds over the central Indian Ocean. Recent research has shown that these established teleconnections
are not as robust as previously thought. Particularly, the relationships between the short rains season and these factors have broken down since 1982, with several seasons having opposite
conditions than what was expected. Furthermore, the debate over which large-scale factors have the most effect on the short rains season is on-going. In this study, the relationship
between the interannual variability of the short rains and known large-scale forcing factors is examined with the goal of answering three questions: 1) Are the factors associated with dry
and wet conditions different before versus after 1982? 2) Why did dry or wet conditions fail to occur when predicted in recent years? 3) Do dry seasons with different combinations of
large-scale factors produce different local patterns in atmospheric circulation? To investigate these questions, different October-November seasons were designated into categories.
Analysis was done on several diagnostic variables for each category of rainfall seasons. Contrary to what was expected, zonal wind field results showed few differences between pre- and
post-1982, giving little answers as to why the relationships between the short rains and these factors has changed since 1982. Omega results highlight influence of a narrow area of
upper-level sinking and rising motion over and just off the coast of East Africa. This study suggests that this feature, while indeed connected to the four established links, could shed
new insight on the short rains interannual variability if evaluated as an individual factor. Results also reaffirmed prior research that shows wet and dry conditions have different
sensitivities to large-scale factors. Additionally, it was found that different combinations of factors, which all produced dry conditions, had different local atmospheric patterns. Some
of the greatest contrasts seen in local patterns were between factor combinations that include the IOZM compared to combinations without it. This suggests that different large-scale
factors could counteract each other. / 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 2015. / August 19, 2015. / east africa, interannual, rainfall, short rains, variability / Includes bibliographical references. / Sharon E. Nicholson, Professor Directing Thesis; Mark A. Bourassa, Committee Member; Vasubandhu Misra, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_291338 |
| Contributors | Smoleroff, Kaitlyn (authoraut), Nicholson, Sharon E. (professor directing thesis), Bourassa, Mark Allan, 1962- (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 department) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (96 pages), computer, application/pdf |
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