Start
April 19, 2024 - 3:00 pm
End
Categories
Convective Meteorology (Mesoscale Dynamics)Convective Meteorology (Mesoscale Dynamics)
Dominic Candela
Using UAS Damage Observations and High Resolution Numerical Simulations to Understand Tornado Evolution over Heterogeneous Land Cover and Terrain
Friday, April 19th, 2024
3:00 pm
NWC 1350
Abstract: Tornadoes impact a wide variety of land surface types with varying degrees of surface heterogeneity and terrain. Through uncrewed aerial systems (UAS), high-resolution aerial imagery captures tornado damage patterns resulting from near-surface flow features occurring in response to the tornado’s interaction in complex terrain and land cover. This study will highlight two cases: the EF-4 Samburg, TN tornado from the 10 December 2021 Quad State tornado outbreak, and the EF-4 Rolling Fork, MS tornado from the 24 March 2023 tornado outbreak. A key limitation of observation is that real-time, near-surface observations of tornadoes are limited spatially and temporally. This study will use high-resolution numerical simulations as a supplement to this data gap.
High resolution numerical simulations are performed using Cloud Model 1 (CM1) to generate tornado-like vortices that have wind speeds that range from 70 m/s to over 140 m/s. In this talk, two preliminary simulations are discussed with different configurations of terrain and surface roughness. A novel approach is used for the simulation with terrain where a terrain following coordinate system is implemented. The simulation with terrain features a tornado vortex traversing a series of three 100 m tall hills. The low level flow field of the tornado vortex is significantly altered as the vortex summits the hill. In another simulation exploring the effects of heterogeneous land cover distributions seen along the Rolling Fork, MS damage path, the surface roughness of the domain is altered to represent a tornado vortex translating across the boundary of an open field and woody wetland. The variability in the structure of the low-level vortex is analyzed through the use of contour frequency
by height diagrams and temporally averaged azimuthal velocity fields. Future work will incorporate the observed digital elevation maps to more accurately represent the land surface topography from the two UAS case studies.