Some of the material in is restricted to members of the community. By logging in, you may be able to gain additional access to certain collections or items. If you have questions about access or logging in, please use the form on the Contact Page.
Mesoscale convective systems (MCSs) provide much of the annual rainfall over central equatorial Africa (CEA) during the March-April-May (MAM) and September-October-November (SON) rainy seasons. The characteristics and propagation of these systems are essential components to rainfall variability in this region. This has economic implications related to agriculture, livestock, and drought monitoring. Understanding MCSs will lead to better regional and global climate models that help predict the effects of the changing hydrologic cycle and heat budget as they relate to MCS activity. This study identifies and tracks MCSs for the 33-year period 1983-2015 using GridSat-B1 cloud top temperature (CTT) data. Characteristics of the MCSs (displacement, duration, speed, heading, minimum CTT, and maximum size) are determined for the MAM and SON rainy seasons. Statistical significance testing is performed to determine if there are differences between the seasons as they relate to the variables and MCS counts. Long-term trends are also examined. Differences and trends are analyzed using the National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR). This study finds statistically significant differences between the rainy seasons domain-wide, but these differences are variable- and latitude-dependent. There is high interannual variability and weak-to-absent trends for nearly all variables in both seasons. The exceptions are the average minimum CTTs, which show less interannual variability and cooling trends. Differences between the seasons are largely due to changes in low-level equivalent potential temperature and large scale circulations. The primary factor for initiation is thought to be thermally-driven gravity waves in the lee of the Great Rift Valley. Low-level vertical wind shear is believed to contribute to the maintenance of MCSs as they propagate, but do not seem to be a major factor for initiation.
A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the Master of Science.
Includes bibliographical references.
Sharon E. Nicholson, Professor Directing Thesis; Jeffrey Chagnon, Committee Member; Vasubandhu Misra, Committee Member.
Florida State University
Use and Reproduction
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.