Korean Peninsula Trapped in Scorching Heat... Cities Hotter Than the 'Daefrica' [News Seolcham]

(33) Humidity in Gwangju Feels Hotter Than in Daegu
Gumi, Gyeongbuk Ranks 1st in Heatwave Days... Daegu 4th
Typhoon Impact Expected to Increase Due to Climate Crisis

Editor's Note'Seolcham' is a newly coined term meaning to refer to detailed explanations. In [News Seolcham], we aim to pinpoint and explain in more detail the parts of the news that require fact-checking or further explanation.

The term 'Daefrica' (Daegu + Africa), once synonymous with scorching heat, is now a thing of the past. Daegu, which was considered the hottest region during summer and nicknamed 'Daefrica' by comparing it to the tropical continent of Africa, has been found to be cooler than Gwangju when considering the perceived temperature.

The perceived temperature is important because it serves as the standard for heatwaves. Since 2020, the Korea Meteorological Administration has changed the heatwave criteria from the highest temperature to the 'perceived temperature,' considering that the feeling of heat varies depending on humidity and wind even at the same temperature. When humidity is high, sweat does not evaporate. It is known that a 10% increase in humidity raises the perceived temperature by about 1 degree Celsius.

On the afternoon of the 16th, when the heatwave continued day after day, heat haze caused by ground heat was rising above Yeouidaero in Yeongdeungpo-gu, Seoul. [Image source=Yonhap News]

Over the past three years, the average perceived temperature in Gwangju was 36.2 degrees Celsius, which is 0.6 degrees higher than Daegu's 35.6 degrees. This has led to the creation of the new term 'Gwangfrica' (Gwangju + Africa).

According to the 'Impact and Response Directions of Heatwaves in Gwangju during Summer' report by the Gwangju Institute on the 7th, the average highest temperature over 20 years (2014?2023) was 30.0 degrees Celsius in Gwangju and 30.6 degrees Celsius in Daegu. However, Gwangju, which is closer to the coast, is more humid than Daegu, which is in a basin, resulting in a higher perceived temperature. Over the past three years, the relative humidity (the current vapor ratio compared to the maximum vapor capacity of the air) was 80.5% in Gwangju and 66.7% in Daegu, a difference of 13.8 percentage points.

Daegu has more heatwave days. According to the Korea Meteorological Administration's climate statistics analysis, calculating the average number of heatwave days from 2020, when the heatwave criteria changed, to August 22 of this year, Daegu experienced an average of 32.8 heatwave days. In contrast, Gwangju had an average of 18.2 days during the same period.

Daegu's heatwave days were ▲31 days in 2020 ▲23 days in 2021 ▲45 days in 2022 ▲27 days in 2023 ▲38 days in 2024 (as of August 22), showing fluctuations each year. Meanwhile, Gwangju's heatwave days have been increasing annually: ▲13 days in 2020 ▲14 days in 2021 ▲19 days in 2022 ▲20 days in 2023 ▲25 days in 2024 (as of August 22).

There are cities that are 'hotter for longer' than Daegu.

On the 13th, Greenpeace, an international environmental organization, investigated the number of heatwave days (perceived temperature above 35 degrees Celsius) during summer (May to September) in 25 cities based on Korea Meteorological Administration data. Over the past 10 years, the city with the most heatwave days was Gumi in Gyeongbuk Province (106 days). It was followed by ▲Gwangju (105 days) ▲Daejeon (96 days) ▲Daegu (83 days). A heatwave warning is issued if the perceived temperature is expected to remain above 35 degrees Celsius for two or more consecutive days, and a heatwave advisory is issued if the perceived temperature is expected to remain above 33 degrees Celsius for two or more consecutive days.

The problem is that the impact of heatwaves is becoming increasingly severe due to the climate crisis. In particular, as sea temperatures rise and more water vapor is generated, larger-scale typhoons than before are occurring more frequently, which can alter pressure systems due to typhoon influence. Currently, the Korean Peninsula is trapped in hot water vapor brought by Typhoon Jongdari (No. 9), and there are forecasts that such heatwaves may continue into September. This is because hot, dry air from the edge of the Tibetan High Pressure descends, forming a hot high-pressure system.

Typhoon Sansan (No. 10), which is moving northward, is also likely to exacerbate the heat. Sansan is expected to move northwestward passing through Japan, and at that time, it may blow warm and humid easterly winds toward the Korean Peninsula, potentially raising temperatures in the western regions.