A Study of a Heavy Rainfall Event in the Middle Korean Peninsula in a Situation of a Synoptic-Scale Ridge Over the Korean Peninsula

Abstract

Observational and numerical studies have been carried out to understand the cause and development processes of the heavy rainfall over the middle Korean Peninsula during 0300 LST-1500 LST 29 June 2011 (LST = UTC + 0900). The heavy rainfall event occurred as the synoptic-scale ridge extended from Western Pacific Subtropical High (WPSH) was maintained over East Asia. Observational analysis indicates that the heavy rainfall is mainly due to scattered convective systems, formed over the Yellow Sea, traveling northeastward across the middle peninsula without further organization into larger systems during 0300 LST-0800 LST, and mesoscale convective systems (MCSs) over the Yellow Sea, transformed into a squall line, traveling eastward during 0800 LST-1500 LST. Organization of convective systems into MCSs can be found over the area of mesoscale trough and convergence zone in the northern end of the low-level jet (LLJ) after 0600 LST. Both observational and numerical investigations indicate that a strong LLJ extended from the East China Sea to the Yellow Sea plays an essential role for the occurrence of heavy rainfall. The strong LLJ develops in between the WPSH and a pressure trough over eastern China. Numerical experiments indicate that the land-sea contrast of solar heating of surface and latent heating due to convective developments are the major factors for the development of the pressure trough in eastern China. Numerical study has also revealed that the mountainous terrain including the mountain complex in the northern Korean Peninsula contributes to the increase of rainfall amount in the middle part of the peninsula.

Environment and Processes for Heavy Rainfall in the Early Morning over the Korean Peninsula during Episodes of Cloud Clusters Associated with Mesoscale Troughs

“…The weak winds over the inland area may be mainly due to the development of the mesoscale ridge over the middle Korean peninsula, which results in a weak height gradient over the inland area. Kim and Lee (2016) also found a similar development of the mesoscale ridge at surface level over the middle Korean peninsula in a similar synoptic situation and related the development to the blocking effect of the terrain along the east coast of the middle Korean peninsula (i.e., the Taebaek Mountain range) based on numerical experiments. These results indicate that the terrain effect may be a factor for the weak winds over the inland area and the stronger convergence ahead of the SWB.…”

Evaluation of Seasonal Climate Predictability Considering the Duration of Climate Indices

“…Several studies have been conducted to develop prediction models and techniques in this field. For example, Kim et al [11] and Kim [12] developed a super ensemble model based on empirical orthogonal function analysis and multiple regression analysis to predict seasonal rainfall three months in advance. Kim et al [13] constructed a monthly temperature and rainfall prediction model using a multiple regression approach with global climate indices as predictors.…”