Date of Award
Master of Science
Department of Engineering Physics
H. Rose Tseng, PhD
From the hot, arid Sahara Desert to the humid, West African monsoon, Africa is a continent with vastly different weather and climate patterns from one region to the next. For this reason, thunderstorm forecasting over Africa has presented significant difficulty. The Gálvez-Davison Index (GDI) was developed for the Americas and provides a more accurate convective forecasting index than the conventional indices for thunderstorm forecasting, including the K, Total Totals, Showalter, and Lifted indices. Previous research using the GDI via the Global Forecasting System (GFS) model data over Africa showed promising results for areal coverage (Donndelinger 2018), especially during the spring through fall months. This study will look to test the GDI via the Global Air Land Weather Exploitation Model (GALWEM) to determine if the GALWEM GDI forecast is able to more accurately forecast the location and areal coverage, as well as resolve airmass thunderstorms, when compared to the GALWEM K Index (KI) and GFS GDI forecast. Results from this study show the GDI and KI have similar location error at the 95% confidence level across the monthly, Zulu time, convective regime, and regional studies. GDI consistently outperforms the KI in terms of areal convection coverage in every study analyzed at the 95% confidence level. The GDI proves to perform best when convection is primarily airmass-based, while the KI performs best when convection is primarily from Mesoscale Convective Systems (MCSs). Furthermore, Kelvin waves and outgoing longwave radiation (OLR) show promise as additional convective forecast tools for Africa. This study contains important information for furthering meteorological understanding of convection and precipitation over the African continent.
DTIC Accession Number
Hanson, William A., "Analysis of the Gálvez-Davison Index for Convective Forecasting Over Africa Using the GALWEM" (2019). Theses and Dissertations. 2202.