This study investigates the atmospheric circulation pattern associated with Korean heat wave in July-August, especially focusing on the role of the east-west teleconnection pattern, using observation data, NCEP/NCAR
reanalysis data for the period form 1973 to 2014, and Global Precipitation Climatology Porject (GPCP) data for the period from 1979 to 2014. Based on the top 20 heat wave cases selected using heat wave total index (HWTI), 42 years are classified into 19 heat wave years and 23 non-heat wave years for composite analysis.
Composite analysis shows that the Korean heat waves are strongly associated with clear five positive geopotential anomaly at 250hPa over the Europe, the Northwestern India, the Korean peninsula, the Bering Sea, and eastern coast of the North America, which are corresponding to Circum-Global Teleconnection (CGT) pattern, indicating that the CGT mode is deeply coupled to the Korean heat wave in July-August. In addition the teleconnection pattern shows barotropic structure except for northwestern India with baroclinic structure, indicating that low level convergence and upper level divergence over the northwestern India is one of the key components for Korean heat wave. The 3rd mode of EOF for geopotential height at 250hPa and the first SVD mode between geopotential height at 250hPa and Korean maximum temperature during July-August confirm that the CGT mode is strongly related to the Korean heat wave. Independent analysis using the Indian Monsoon Index (IMI) also confirms that strong Indian summer monsoon induces high pressure anomaly at 250hPa over the Korean peninsula through the CGT pattern and thereby provide a favorable synoptic pattern for shortwave heating, adiabatic heating, and the block of moisture transport to the Korean peninsula. Precipitation anomaly related to strong Korean heat wave is also consistent with the associated synoptic pattern above with negative precipitation anomaly over the Korean peninsula and positive precipitation anomaly over the southeastern China and northwestern India.
Thus this study emphasizes that the east-west teleconnection pattern originating the upper troposphere over the northwestern India is one of the key components for the amplification of the Korean heat wave in July to
August, indicating that it needs the monitoring of Indian summer monsoon for the prediction of Korean heat wave.