Publication Date

Summer 2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Climate Science

Advisor

Sen Chiao

Keywords

Dust, Hurricanes, Lightning, Saharan Air Layer, tropical cyclogenesis, Tropical meteorology

Subject Areas

Meteorology; Atmospheric sciences

Abstract

In this study, the results of an observational analysis and a numerical analysis on the role of the Saharan Air Layer during tropical cyclogenesis (TC – genesis) are described. The observational analysis investigates the interaction of dust particles and lightning during the genesis stage of two developed cases (Hurricanes Helene 2006 and Julia 2010). The Weather Research and Forecasting (WRF) and WRF – Chemistry models were used to include and monitor the aerosols and chemical processes that affect TC – genesis. The numerical modeling involved two developed cases (Hurricanes Helene 2006 and Julia 2010) and two non – developed cases (Non – Developed 2011 and Non – Developed 2012). The Aerosol Optical Depth (AOD) and lightning analysis for Hurricane Helene 2006 demonstrated the time – lag connection through their positive contribution to TC – genesis. The observational analyses supported the fact that both systems developed under either strong or weak dust conditions. From the two cases, the location of strong versus weak dust outbreaks in association with lightning was essential interactions that impacted TC–genesis. Furthermore, including dust particles, chemical processes, and aerosol feedback in the simulations with WRF – CHEM provides results closer to observations than regular WRF. The model advantageously shows the location of the dust particles inside of the tropical system. Overall, the results from this study suggest that the SAL is not a determining factor that affects the formation of tropical cyclones.

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