WRFによる竜巻地表近傍風の特性に関する研究

摘要

The F3 supercell tornado hit Tsukuba City in eastern Japan is one of most destructive tornado ever recorded in Japan which caused one fatality and great property damage. To explore the wind characteristics of tornado in realistic condition, the Weather Research and Forecasting Model (WRF) model has been employed and successfully regenerates this tornado process. Simulation by WRF model is conducted by triply nested domains downscaling horizontal grid resolution from 1 kilometer to 40 meters. The innermost domain reproduced tornado wind field shows a good agreement to the observed typical tornado and experimental results in average wind characteristics. In this study, not only the symmetric averaged wind characteristics tornado is compared with recent tornado wind field model; the spatial and temporal variation of tornado is also emphasized. Simulated multiple vortexes structures associated with central downdraft inside the tornado is observed. The importance of low level updraft to tilt horizontal vorticity to vertical vorticity is exhibited.