The Characteristics of Summer Heavy Rains from Atmospheric River Related to Low Level Jets & Typhoons, MJO & ENSO, and Monsoon

This study investigates the causes of summer heavy rains on the Korean Peninsula from 2018 to 2024 by analyzing the relationship between Total Precipitable Water (TPW) and atmospheric fluctuations such as low-level jets, typhoons, the Madden-Julian Oscillation (MJO), the El Niño-Southern Oscillation (ENSO), and the monsoon. Using observational data and meteorological reanalysis, the study explores how these factors influence TPW. The analysis shows that tropical cyclones and typhoons near the thermal equator in the Indian Ocean and Western Pacific form atmospheric rivers that carry water vapor to the Korean Peninsula. In one case, TPW was influenced by a tropical cyclones in the Indian Ocean, forming a monsoon front linking China, Korea, and Japan, causing heavy rainfall. In the second case, typhoons in the Western Pacific strengthened the monsoon front and then moved itself directly toward the peninsula, both leading to severe rains. In the third case, heavy rainfall occurred as a result of typhoons itself moving directly from the Western Pacific or further east. The findings highlight the key role of tropical cyclones and typhoons in determining TPW distribution and heavy rainfall on the peninsula.