| This dissertation emphasizes the importance of regional climate modeling as a tool that is nowadays very commonly used for weather and climate modeling applications. This evaluation was completed thru analysis of dynamical downscaling ability of the NCEP Regional Spectral Model v.97 (NCEP RSM97).; Regional climate modeling became a very powerful tool in the field of weather and climate prediction mainly because of its high operational resolution that provides the ability to resolve regional topography details and regional climate processes that can not be accessed yet by the current Global Circulation Models (GCMs). Current advances in regional climate modeling are enabling the scientific community to better understand how these processes impact the climate and weather features of the region of interest on both, the regional and global scales.; The purpose of this dissertation is twofold. Firstly, it explores the technical nature (the downscaling ability) of the NCEP RSM97 thru the application of a so-called "Big Brother Experiment (BBE)," and secondly, it analyzes this particular model's ability to capture some real life climatic features. The BBE is an experiment designed to test the regional model nesting strategy, and clearly differentiates the errors in the simulations due to a nesting technique rather than the model errors, or problems with the initialization or verification of data. In this dissertation, this experiment is applied over the tropical Atlantic and Northeast Brazil, as well as over a couple of midlatitude domains located over the North American continent. The real life capability of this model is tested over the Sahelian region of Western Africa, where ensembles of downscaling experiments were used to capture the interdecadal rainfall trend over that region, comparing the 1950s vs. 1980s interdecadal sea surface temperature contributions, and tropospheric warming mechanism in relation to the Sahelian rainfall. Furthermore, some land-surface experiments were completed to gain a better understanding of the effects of the desertification on this region.; All of these experiments have demonstrated thru application of the NCEP RSM97 that the regional climate modeling is a very important tool for an assessment of regional climate processes. |
