[A-AS03] Extreme Events and Mesoscale Weather: Observations and Modeling

[AAS03-P14] Sensitivity Experiments of Atmospheric Initial and Boundary Conditions Shifts for Extreme Rainfall Event Associated with Low-level jet in Kinki District, Japan

*Ono Akiyuki¹, Kosei Yamaguchi¹ (1.Disaster Prevention Research Institute, Kyoto University)

Keywords:linear-shaped precipitation systems, atmospheric initial and boundary conditions shifts, cloud-resolving model, low-level jet, precipitation

Low-level jets along the Kii Channel and terrain forcing play a crucial role in the development and maintenance of mesoscale convective systems (MCSs) in the Kinki District. This study examines the sensitivity of precipitation during an MCS event in July 2012 using the atmospheric initial and boundary condition shifting method to clarify the factors contributing to precipitation intensification. For the numerical simulations, we applied the Cloud Resolving Storm Simulator with a 500 m horizontal resolution to capture convective cloud dynamics. The control run successfully reproduced a line-shaped rainband similar to that observed in radar data. Sensitivity experiments with a northward shift of dynamic and thermodynamic variables below 700 hPa, referred to as lower-level shifts, showed an increase in precipitation and a northward displacement of the precipitation area. Further analysis of the environmental characteristics suggests that higher equivalent potential temperature and stronger southward winds in the lower-level of Kii Channel contributed to precipitation intensification. Future research should explore the dynamics of flow along the channel, particularly its interaction with depressions and the western Pacific subtropical high.