This is the view of Gwangjingyo Bridge on the Han River on January 20th.

Ice cubes are floating, and the Olympic Bridge is covered with snow in the distance, and it even looks as if the south and north of the Han River are connected.

The title of the photo is <The cold wave that continues every day, the Han River is full>, which is a fitting title.



However, the Han River was not 'officially' frozen.

More stringent conditions must be met for a declaration of 'freezing of the Han River'.

Let's go into more detail.


Conditions for the official freezing of the Han River

If you look at the <Seasonal Observation Guidelines> published by the Korea Meteorological Administration, there is an item called 'Ice and Thaw Observation of Rivers and Rivers'.

The 'freezing of rivers and rivers' defined here is "a state in which the water surface is completely covered by ice and cannot be seen" and "it has nothing to do with the thickness of the ice".

In other words, if it meets the condition that it is frozen and cannot see through the water, then whether it is thin ice or thick ice can be regarded as 'freezing'.

If you look at the picture above again, it looks so frozen.

But why didn't it freeze?

The next condition, 'observation location', is a problem.



In the same guideline there is a description of the observation site.

There are places to observe ice and thawing in each region, such as Seoul, the metropolitan area, Busan, Ulsan, Daegu, and Pohang. It is a band-shaped range". Seohocheon in the metropolitan area is 'a band-shaped range between north and south about 20m downstream of the first pier of Seodun Bridge, the upstream point of Seohocheon'. (Seohocheon is in Suwon.) This observation site is ' It must be 'freeze', that is, when it is frozen and the water cannot be seen through it, it is officially frozen.



Since the observation, the Han River has not frozen eight times...

this year too?

So what about the observation itself?

The basics of observation are 'visual observation', and it is said that the priority is to confirm it with the naked eye.

They check it with CCTV first, but if it is frozen, a person goes and checks it with their own eyes.

The official freezing of the Han River is a meaningful observation during this period, so the Seoul Meteorological Observatory explains that the head of the Seoul Meteorological Observatory goes out and inspects it every day.



Park Jeong-min, a forecaster at the Korea Meteorological Administration, said, "The freezing cold on the Han River lasts for several days with the morning minimum temperature dropping below minus 10 degrees Celsius, and the daytime temperature should also stay below freezing and the wind should blow a little bit." So there is a possibility that it will not freeze this year.” 



It's not the only time the Han River hasn't (officially) frozen this year.

The Han River ice has been observed since 1906, but it was not observed even in 2019, the most recent one.

Prior to that, eight times of frozen Han River were not confirmed until 1960, 1971, 1972, 1978, 1988, 1991 and 2006.

Only 8 times in 115 years.

If it is confirmed that the Han River has not frozen until this year, the total number will increase to nine. 


Less freezing of the Han River due to global warming?

It's still a bit...

It seems that the gap between the unfrozen years has narrowed a bit, right? It was once each in the 80s, 90s, and 2000s, but after 2019, it will be the first time in 3 years that the Han River freezes again (probably). Of course, there is still the possibility that the Han River will be officially frozen with strong cold in February. 



Could this be linked to global warming? As the temperature rises, the freezing of the Han River itself is decreasing, and there may be more days when the Han River does not freeze! It may or may not be. It is difficult to connect directly with the fact that the Korean Peninsula is getting warmer with or without 'freezing of the Han River' in the next few years. The World Meteorological Organization averages over 30 years when calculating average climate values. And we update it every 10 years. It can be said that it is a meaningful change only if we look at that period of time.



I will close this article by looking at one data as a reference. I looked up the number of freezing days at the National Climate Data Center (data.kma.go.kr) operated by the Korea Meteorological Administration. Among them, if we look at the number of freezing days at the Seoul branch, the average number of frozen days for 30 years from 1991 to 2020 was 107.7 days. It seems that the number of freezing days is gradually decreasing? When I looked up the number of freezing days at the Suwon branch in Gyeonggi-do, I found that the average number of consecutive freezing days for 30 years from 1991 to 2020 was 113.5 days. The Han River is freezing less because of global warming! It's still vague to say.