The development and maintenance of MCS by SST variation effects over the Yellow Sea, Korea

Heavy rainfall causes serious disasters such as flash floods and landslides that occur in a small area for a short time. To reduce damage of human life and property, it is important to understand the characteristics, structure and formation of mesoscale convective system (MCS). The heavy rainfall-producing MCS from Yellow Sea to land was investigated using observations and numerical simulation. The Sea Surface Temperature (SST) value higher than the annual mean plays a role in development of MCS and mid-latitude heavy rainfall events. The aim of the study is to examine impact of SST on the development and maintenance of MCS and understand the physical mechanisms of heavy rainfall event.

The linear-MCS developed from Yellow Sea to Gunsan area that lead to heavy rainfall with accumulated rainfall more than 400 mm. We performed CReSS (Cloud-Resolving Storm Simulator, Tsuboki and Sakakibara, 2002) model of Nagoya University to investigate the reason of effects of SST variation on MCS over ocean. The control experiment (CNTL) is successfully simulated with reproduceing linear MCS and rainfall pattern compared with observation. The latent heat flux from the sea surface appears strongly and it is associated with sea-atmosphere interactions. In sensitive experiment of 1 ºC decreasing SST (RSST), the simulated linear MCS was weak and latent heat flux was rapidly reduced. The higher SST value than annual mean contributed to formation and development of linear MCSs from Yellow sea to land.