A Study on the Characteristics of Extratropical Cyclones on the Korean Peninsula through the Analysis of Heavy Rain in Summer

The Korean Peninsula is located in a mid-latitude region. The weather in August is hot and humid with a little rainfall due to the expansion of the North Pacific High. However, severe weather events such as heavy rain are sometimes caused by extratropical cyclones. Despite the vanishment of the monsoon front(Changma), it rains heavier than the summer monsoon period. This is attributable to the effects of extratropical cyclones. The cyclones formed in central China and moved toward the southwestern part of the Korean Peninsula, causing heavy rain in the southern regions of South Korea. The amount of precipitation is approximately 200㎜ in the southern coast and 150㎜ in the southern inland. This study has analyzed the primary features of extratropical cyclones affecting the Korean Peninsula by using Korea Meteorological Administration numerical model(Unified Model) and observation data including radar and satellite images. The following conclusions can be drawn from the analysis results. 1. The cyclones are meso-alpha scale extratropical cyclones at the edge of the synoptic scale. 2. The cyclones are generated by an upper level divergence and through. 3. SW-ly(or Low Level Jet) enhanced by the cyclones provide abundant moisture for heavy rain. 4. Symmetric Instability can be formed within extratropical cyclones by SW-ly and it can lead to heavier rainfall. The results are expected to be utilized for weather forecast and warning in the case of heavy rain.