대기권밖일사량을 활용한 체감온도 산출 보정기법 개발 및 적용성 평가 = Development and Applicability Assessment of a Bias Correction Method for Systematic Errors in Feel Temperature Using Extraterrestrial Radiation

다국어 초록 (Multilingual Abstract)

Heatwaves have emerged as severe meteorological disasters that pose significant public health threats worldwide; their frequency and intensity are increasing with climate change. The Korea Meteorological Administration operates a heatwave warning system that estimates the daily maximum feel temperature based on an empirical relationship with the Wet-Bulb Globe Temperature (WBGT). However, wet-bulb and globe temperatures are classified as nonstandard meteorological variables, limiting their real-time application. Consequently, the current system relies on empirical equations that use only air temperature and relative humidity, introducing a systematic bias. This study aimed to characterize these biases and propose a novel correction approach based on extraterrestrial radiation. From May to September 2024, globe temperature observations were collected at three sites—Incheon Airport, Seoul Songwol-dong, and Seogwipo in Jeju—to obtain the reference feel temperatures. The analysis revealed that the current estimation method systematically underestimates feel temperature during daytime because it insufficiently represent solar radiation effects, particularly by 2-3℃ under high solar radiation conditions, and overestimates it at night by neglecting radiative cooling. Solar radiation-related variables were identified as major contributors to systematic errors. Extraterrestrial radiation alone accounted for 16.0-32.6% of the bias variance without requiring additional weather measurements. A bias-corrected feel temperature model incorporating extraterrestrial radiation was developed, reducing the average root mean square error from 0.97-0.63℃ and mean absolute error from 0.84-0.48℃ during the validation period. The model achieved a stable performance around noon, when solar irradiance peaked, effectively suppressing extreme errors. This study demonstrates that extraterrestrial radiation can serve as a practical and effective variable for correcting systematic bias in feel temperature estimates within Korea's heatwave warning system.