[A-AS04] Extreme Events and Mesoscale Weather: Observations and Modeling

[AAS04-08] Evaluation of tornadic environments, their trends, and projected changes in Japan

*Sho Kawazoe¹, Masaru Inatsu¹, Mikiko Fujita², Shiori Sugimoto², Yasuko Okada³, Shingo Watanabe² (1.Hokkaido University, 2.Japan Agency for Marine-Earth Science and Technology, 3.Meteorological Research Institute)

Keywords:Tornado, Climate change prediction, Large ensemble simulation, Extreme events

Despite their socio-economic impacts, little is known about how tornadic activity in Japan has changed over the last several decades or how they may change in future climates. To investigate this, we first examine environmental conditions associated with reported tornados in Japan by using pseudo-soundings from the high-resolution fifth-generation ECMWF reanalysis. Discriminators of F2+ tornado environments are determined by computing thermodynamic (convective available potential energy, convective inhibition, lifting condensation level, and the K-index), kinematic (bulk wind difference and storm-relative helicity), and multivariate tornado parameters (energy helicity index, K-helicity index, and the significant tornado parameter). Consistent with previous studies, F2+ tornadoes occur in environments with higher instability and helicity but are better distinguished when using multivariate tornado parameters. Recent trends (1979-2021) indicate that F2+ tornado environments have increased significantly in some regions over the last four decades, though variability exists in their magnitude based on region or the tornado parameter utilized. We also examined future changes in F2+ tornado environments using the 2-K warming scenario from the database for Policy Decision-making for Future climate change. Results depict a robust increase in F2+ environments in almost all regions in Japan, indicating the potential for more tornadoes to occur in the future.