Tornadogenesis in a High-Resolution Simulation of the 8 May 2003 Oklahoma City Supercell
| Autor: | Ming Xue, Ming Hu, Alexander D. Schenkman |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Journal of the Atmospheric Sciences. 71:130-154 |
| ISSN: | 1520-0469 0022-4928 |
| DOI: | 10.1175/jas-d-13-073.1 |
| Popis: | A 50-m-grid-spacing Advanced Regional Prediction System (ARPS) simulation of the 8 May 2003 Oklahoma City tornadic supercell is examined. A 40-min forecast run on the 50-m grid produces two F3-intensity tornadoes that track within 10 km of the location of the observed long-track F4-intensity tornado. The development of both simulated tornadoes is analyzed to determine the processes responsible for tornadogenesis. Trajectory-based analyses of vorticity components and their time evolution reveal that tilting of low-level frictionally generated horizontal vorticity plays a dominant role in the development of vertical vorticity near the ground. This result represents the first time that such a mechanism has been shown to be important for generating near-surface vertical vorticity leading to tornadogenesis. A sensitivity simulation run with surface drag turned off was found to be considerably different from the simulation with drag included. A tornado still developed in the no-drag simulation, but it was much shorter lived and took a substantially different track than the observed tornadoes as well as the simulated tornadoes in the drag simulation. Tilting of baroclinic vorticity in an outflow surge may have played a role in tornadogenesis in the no-drag simulation. |
| Databáze: | OpenAIRE |
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