Effects of environmental shear and buoyancy on simulated supercell interactions

supercell;supercell interactions;storm interactions;severe weather;numerical modeling

Wendt, Nathan Allen ; Rauber, Robert M ; Jewett ; Brian F

关键词: supercell;    supercell interactions;    storm interactions;    severe weather;    numerical modeling;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/89099/WENDT-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This study examines the role that buoyancy and vertical wind shear play inmodulating the relationship between storm interactions and storm severity.Using an idealized numerical model, 240 supercell interactions are simulatedunder systematically varied amounts of buoyancy and vertical wind shear.Small changes in buoyancy or vertical wind shear have signi cant impacts onpost-interaction storm morphology. A wide amount of variation in low-levelrotation is seen across the simulation suite. Two-cell storm simulations arenot always stronger than one-cell control simulations. Migration of low-levelvertical vorticity centers is ubiquitous through all runs, but orientation ofand interaction between two storms' gust fronts modulates where the vortic-ity center will end up. Gust fronts in better alignment have more vorticitycenters reach an updraft where they are stretched and intensi ed. With re-spect to storm mode, higher buoyancy produced less classic supercells whilehigher shear produced more classic supercells. High precipitation supercellswere favored with two-cell simulations where the second cell was directly tothe southwest of the control cell. Secondary cells that were close to the con-trol merged quickly and were often stronger than simulations with large cellseparation distance. Further questions remain with trajectories and machinelearning algorithms are tthe next steps for a more detailed analysis of thislarge data set.