April 22, 2022 - 3:00 pm
April 22, 2022 - 4:00 pm
CategoriesConvective Meteorology (Mesoscale Dynamics)
Convective Meteorology (Mesoscale Dynamics)
Development of a Radar Simulator and Statistical Techniques to Compare Weak and Strong Tornadic Supercells in Very High-Resolution Numerical Simulations
Rachael N. Cross
Friday, April 22
Not only are supercells responsible for the majority of observed tornadoes, but they produce the strongest and longest-lived tornadoes. While there have been many projects that have focused on how such tornadoes form, it is still largely unknown what differentiates storms that produce weak tornadoes versus those that produce more intense tornadoes. Some studies have assessed the correlation between mesocyclone width with tornadic strength while modeling studies have looked at environmental factors that influence tornadic strength and formation. In very few studies, however, statistical methods such as Empirical Orthogonal Function (EOF) and Fourier analysis have been used to look at leading patterns and processes to differentiate supercells that produce weak and strong tornadoes. Furthermore, applying these analyses to radar data and determining patterns across both dynamic and polarimeteric radar variables is needed to objectively examine high-resolution radar datasets. In particular, objective methods that can analyze the entirety of a radar dataset are especially needed. With this in mind, this project will use Cloud Model 1 (CM1) data of tornado-producing supercells. Specifically, the analysis will begin by comparing two simulations: one that produces a short-lived, weak tornado and one that produces a longer-lived, strong tornado. A radar simulator will be developed that uses the CM1 microphysics parameters and outputs radar reflectivity factor (Z), differential reflectivity (ZDR), and specific differential phase (KDP). With the radar simulator and the CM1 model output, three statistical methods will be employed to define structures and processes unique to supercells that produce more intense tornadoes. These statistical methods are 1) EOF analysis, 2) Fourier (or harmonic) analysis, and a new technique that is new to meteorological analysis, 3) Entropy Field Decomposition (EFD). The analysis will begin with the first and third method, while the second method will be done during the later stages of this project. The eventual goal is to compare high-resolution radar observations with idealized simulations of the same case, and novel analysis techniques such as EFD are needed to accomplish this comparison.