Human-Perceived Temperature Changes in South Korea and Their Association with Atmospheric Circulation Patterns

This study investigates the spatiotemporal characteristics of human-perceived temperature (HPT) data, which describe the joint effects of temperature and humidity on the human body, and examines the related large-scale atmospheric circulation patterns for the summer season (July-August) in South Korea using trend and composite analyses. The increasing trend of HPT was stronger than that of the maximum, mean, and minimum temperatures during 1981-2018. There was an abrupt change in HPT between 1981-2009 and 2010-18, which is likely caused by the northward upper-level subtropical jet, strengthened downward motion, anomalous anticyclones around South Korea, and increased sea surface temperature over the western North Pacific Ocean, which are related to the enhancement and western expansion of the western North Pacific subtropical high (WNPSH). These results highlight the importance of the activity of the WNPSH in the variability of HIYI' in South Korea. When the western edge of the WNPSH is located in the northwest, a positive geopotential height anomaly at 500 hPa is centered over South Korea, which is associated with high temperatures and low relative humidity. The southwestern extension of the WNPSH modifies the wind circulation pattern and brings warm and moist air from the West (Yellow) Sea along the ridge line of the WNPSH. Eventually, it leads to extreme HPT, associated with high relative humidity and temperature over South Korea, particularly in the southern part of the country. Therefore, we concluded that monitoring and predicting the location of WNPSH and understanding the mechanism and factors influencing the movement of WNPSH under global warming are necessary for predicting and coping with extreme HPT.

Automated summary

This study found that the increasing trend of HPT in South Korea during the summer season was stronger than that of maximum, mean, and minimum temperatures from 1981 to 2018, with a sudden change between 2010-18. The results highlight the importance of the activity of the Western North Pacific Subtropical High (WNPSH) in the variability of HPT in South Korea, emphasizing the necessity of monitoring and predicting the location of WNPSH and understanding the mechanism influencing its movement under global warming for predicting and coping with extreme HPT.