Structure and evolution of line-shaped convective systems associated with Changma front during GRL PHONE-09: 6 July 2009 case

Abstract

This study investigates the structure and evolution of line-shaped convective systems (LCSs) associated with the Changma front observed over Chujado in the southwestern Korean Peninsula by using intensive observational data from upper-air sounding and Doppler radars. LCSs embedded as a multicellular precipitation system developed north of the warm front and persisted for 4 h. With continuous new cells development, the convective cells gradually strengthened and merged into the LCSs and exhibited a high low-level mixing ratio, weak vertical wind shear, and negligible instability. A rear-to-front jet corresponding to a low-level jet (LLJ) was concurrent with a high equivalent potential temperature (θe) environmental inflow over the warm front, which suggests that the rear-to-front jet with moist air induced destabilization. Three-dimensional kinematic and reflectivity structures of the LCSs exhibited homogeneous southerly and southwesterly winds with height, small horizontal wind shear, and convergence. Transfer of positive u and v momentum upward by convective eddies into the LCSs and of horizontal momentum occurred through organized convection; both these transfers acted to intensify the LLJ. © 2014 Royal Meteorological Society.