Study on the thermodynamic characteristics of heavy rainfall events in the southern Korean Peninsula

This study investigated the impacts of low-level thermodynamic structure and water vapor on heavy rainfall events in the southern Korean Peninsula during the 2016 summer intensive observation period. An intensive dataset of mobile observation vehicle (MOVE), with high temporal resolution rawinsonde soundings and global navigation satellite system (GNSS) observations in Geochang (GC) supersite, was used. We divided study events into two heavy rainfall cases to compare the characteristics of representative summer heavy rainfall with different synoptic conditions. Case 1 has localized heavy rainfall associated with the Changma (summer monsoon) and Case 2 has convective instability. The temporal behavior of precipitable water vapor (PWV) retrieved from the MOVE-GNSS data demonstrated that during Case 1, heavy rainfall events experience a steep decrease after a long increasing trend. However, the most intense rainfall events occurred after a rapid increase in PWV during Case 2. In Case 1, the mean static stability at >2 km altitude was variable for all periods (in the order of after > before > during rainfall), whereas in Case 2, this was less variable with time and had generally higher convective instability close to the surface, compared with Case 1. In addition, Case 1 demonstrated the progression of a vertical wind structure connected with a quasi-stationary frontal passage (e.g., veering winds at low levels before rainfall), whereas Case 2 demonstrated a nearly homogeneous southwesterly wind from the surface to an altitude of 5 km.