Insight from the data can help to inform Seoul’s smart city plans
Results from Seoul’s analysis of its network of 1,100 IoT sensors reveals that the temperature of the city centres were 2.32°C higher in summer and 2.16°C higher in winter than the mountains.
The Seoul Data of Things sensor network (S-Dot) is installed in major mountains, riversides, and downtowns, and collects 17 kinds of urban data, including temperature, humidity, illumination level, noise and ultrafine particles, every two minutes.
The analysis was based on data collected from April 2020 to March 2021 and examines how Seoulites’ living environments differ by each area’s characteristics.
Data collected by S-DoT is being used to check urban phenomena and establish data-based smart city policies. The difference in city centre temperatures identifies an urban heat island effect as these areas were 1- to 3° C hotter on average.
“S-DoT serves as a densely woven, optimum infrastructure to look at the urban phenomenon,” said Lee Weon-Mok, director general of the Smart City Policy Bureau. “The SMG [Seoul Metropolitan Government] will provide services and policies that can improve the value of the city and practically helps our citizens’ lives by converging and analysing data of S-DoT along with the data from the public, private, and academic sectors.”
In 2020, on the sunniest and hottest day, the downtowns were 3- to 3.4°C or up to 7°C hotter than the mountain, and 1.6- to 1.9°C, or up to 4.3°C hotter than the riverside. The temperature gaps between the downtown and mountain and between the downtown and the riverside are affected by numerous factors such as the regions, time, weather, and season, but data showed that the bigger the humidity gaps, the bigger the differences in temperature.
“The SMG will provide services and policies that can improve the value of the city and practically helps our citizens’ lives by converging and analysing data of S-DoT along with the data from the public, private, and academic sectors”
Unlike the Korea Meteorological Administration, which measures the climate in a standardised environment, S-DoT, installed in the city centre, is influenced by urban conditions such as adjacent buildings, roads, and air conditioning systems. Moreover, since S-DoT can be found outdoors – in Seoul’s mountains and Hangang Parks – as well as in crowded buildings, roads, bus, and subway stations, comparison between various areas of the city is possible.
In summer, people in the city centre felt displeasure due to humidity earlier than those in the mountain or riverside areas, and such feelings lasted two to three weeks longer.
Compared to downtowns, mountain areas’ ultrafine particle level was 11.5 ug/m3 lower from November to March on average. From February to March, it was lower by 15 ug/m3, showing a more significant gap.
In other seasons than winter, the levels of the ultrafine particles showed a generally similar pattern. City centres are usually 1- to 3°C hotter in summer than the mountain and riversides. Hence, an increase in air conditioning bills is expected, but as it is 1- to 2°C warmer in winter as well, there would be a reduction effect in the heating expenditure.
As S-DoT analysis demonstrates that in summer, the displeasure is higher and lasts longer in comparison with the other two areas, summer is more likely to have violent crimes and traffic accidents. As a result, it is necessary to take preventive measures to stop such incidents in city centres. As the heat index is higher and hot and humid tropical nights last longer in the centre in summer, the city needs to reinforce its management system on socially isolated single-person households, seniors, and other groups of people with special needs.
S-DoT’s collected data will be provided to Seoul citizens as urban life environment information in real-time at Smart Seoul Map at map.seoul.go.kr from August.
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