Influence of the SST Variations on the Development of MCS over the Yellow Sea, Korea

An extreme rainfall-producing mesoscale convective systems (MCSs) occurred over the Yellow Sea, Korea on 13 August 2012, recording 430 mm of rain in less than 12 hours. To better understand the factors of heavy rainfall-producing MCSs underlying this event, the formation and development mechanisms of MCSs causing the heavy rainfall were examined using observation and cloud resolving simulation. The southwesterly warm and moist air from low latitude were largely formed over the Yellow Sea. MCSs mode is Echo Training/back-building (BB) type. These synoptic environments and MCSs mode are advantageous to make extreme rainfall over the Yellow Sea. The heavy rainfall-producing MCSs are dependent not only at the atmosphere but also at sea. The sea surface temperature (SST) field of the Yellow Sea in this event was 1.1°C higher than 10-years mean, and existed local warm pool (>28.5°C). To investigate the impact of the SST variations on MCSs over the Yellow Sea, we performed sensitivity experiments using the Cloud Resolving Storm Simulator (CReSS, Tsuboki and Sakakibara 2002). The MCSs were developed in warm SST field in numerical simulation results. In addition, the low-level convergence and latent heat flux is relatively enhanced in MCSs. Therefore, SST variation plays a role in the continuous development of convective cells over the Yellow Sea.

Acknowledgements

This research was supported by the Korea Meteorological Institute under Grant KMI 2018-05410.