[Newsship] Is this heat these days, 'hot heat'?

hot.

so hot.

The word 'too' is not enough.

There are several words to describe the aspect and feeling of heat.

The expression 'severe heat' appears frequently in articles dealing with the weather, various words, and writings.

A few days ago, in a media article about a wildfire near Yosemite National Park in the western United States, a wildfire occurred and it was difficult to put out.

But, what does the word 'heat' mean?

What do you think?

(※ Voting function is not supported on the portal. You can do it on the SBS News website or app.)

The answer is number two.

If you look up the standard Korean dictionary of the National Institute of the Korean Language, it is defined as "the heat that is difficult to endure as it is steaming because the humidity and temperature are very high."

The weather near Yosemite National Park in the United States, where the wildfire took place, had a temperature of over 31 degrees and a humidity of only 15%.

This dry heat, when forests dry up and become firewood, is not called sweltering heat.

What does the word 'hot' mean?

If you look at the etymology of the word 'severe heat', it is 'water + heat'.

It's not 'ignorance + hot'.

Such is the explanation of the etymology published in 'Online Ganada' of the National Institute of the Korean Language.

Here, the question is likely to arise.

Where did the d stand of 'water' go?

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In Korean, there is a phonological phenomenon called 'dropout'.

When two words are combined to form a single word, if the preceding consonants are ㄴ, ㄴ, ㅅ, or ㄱ, a phenomenon may occur that the sound at the end of the preceding word is dropped.

Because it's easy to pronounce.

For example:

Brush + Wood -> Pine / Daughter + Mother -> Daughter / Bow + Flesh -> Arrow

Of course, there are quite a few exceptions.

'Water + Nanri' is written as 'Water Nanri' (not Mu Nanri), but 'Fire + Nori' is written as 'Bunori', not as 'Bunori'.

'Liquor + Glass' is just 'Liquor Glass'.

Language is formed and changed as a habit of a group, so it is not too stressful to wonder why d is dropped here and remains there.

However, if you use the word while thinking about the etymology, you can convey the meaning more accurately.

Steamy heat and scorching heat: steaming or grilling?

There are several types of heat.

'Sultry heat', whose etymology just looked at, is representative, and 'steamer heat', 'scorching heat', 'steam heat', and 'cauldron heat' are used a lot.

These days, it is difficult to see in the language life of ordinary people, but there are words such as 'severe heat' and 'strong heat'.

There are also a lot of 'heatwaves' in the news.

All of these words mean 'extremely hot' or 'very hot', and their usage varies depending on factors other than temperature.

That's right, humidity.

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Think of a time when you put corn, rice cakes, or dumplings in a steamer and steam it.

Steaming is a cooking method in which hot steam is generated by heating the bottom with water to cook the ingredients.

It is hot and humid, just like the feeling of hot steam.

'Steaming heat' is such a heat.

'The heat of the steam room' would be a similar expression.

'Sultry heat' is 'water + heat', so it is a steaming system.

There are also different types of heat.

The sun is hot and the temperature is high, but the humidity is not high.

‘Sunshine heat’ is a typical expression.

Articles in the media tend to write 'scorching heat' when the humidity is less than 70% and the temperature is high.

'Cauldron Heat' is also in this series.

It refers to extremely hot weather, like the energy of a wood fire that heats a cauldron.

Although it is not used often these days, 'strong heat' is also a word to express dry heat.

The heat that lasted for several days without cooling down the rain was called 'gang heat'.

If so, what is called 'sultry heat' when it is humid?

At what level of humidity is 'hot'?

There is no standard set by the Korea Meteorological Administration as to what is considered hot when the humidity is above a certain percentage.

Then, I asked SBS meteorologist Jung Gu-hee, who used the expression 'severe heat' in what cases the weather report used.

Jeong said, “It is not possible to define a standard such that when the humidity is more than a few percent, it is called sweltering heat. The sweltering heat is either 1) humid southern air comes in from the edge of the North Pacific high pressure, or 2) enters the North Pacific high pressure area at all and the humidity is high. It's an expression I use at times."

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Humidity changes frequently throughout the day and there are large variations even by region, so it is not possible to determine 'severe heat' with only a few percent of humidity. is to call

If so, does this week's weather correspond to 'severe heat'?

If you look around Mok-dong, Seoul, where SBS is located, the temperature fluctuated between 32 and 35 degrees Celsius in the middle of the day this week, while the humidity stayed in the 50 to 65 percent range.

Although it was hot, it felt less steamy, so this week's midday heat in Seoul was closer to the scorching heat of the general public than the sweltering heat.

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On the other hand, in Seoul this week, the humidity rose to around 80% after the sun went down.

This is not because moisture, which was absent during the day, came from somewhere at night, but because the amount of moisture in the air remained the same (ie, the absolute humidity remained the same) and the temperature dropped.

Even the same air can hold different amounts of moisture depending on the temperature.

(That is, 'relative humidity' is different. What we usually call 'humidity' is actually 'relative humidity'.) Hotter air can hold more moisture.

As the air cools, the moisture it can hold decreases.

This principle works for dew to form when the temperature drops at dawn.

This week, even though it was a little hot during the day, it was tolerable, but if you feel damp by the evening, it's because of the relative humidity.

So what about the overall?

Is this week's heat worthy of being called 'sultry'?

Meteorological correspondent Jung Gu-hee said, 'It can be called sweltering heat' considering not only Seoul, but also various regions such as the southern region and the plight of people working outside.

In terms of pressure layout, the hot and humid North Pacific high pressure is increasingly having a strong influence, so it is said that the article can describe the situation as 'severe heat'.

In addition, the 5th typhoon Songda, which developed in the tropical depression, is coming up, and hot and humid air is expected to be added.

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Does the actual heat feel different?

Humidity and temperature

Even at the same temperature, the sweltering heat is better to endure than the sweltering heat.

If you take shelter in the shade and even a slight breeze blows, it's the sweltering heat that makes it a little more bearable.

Such is the case in southern Europe such as the western United States in summer or Italy and Spain.

The reason why people in desert regions in the Middle East wear long clothes that come down to the wrists and ankles is because the humidity is low, so you only need to cover the sun.

If the Middle East had high humidity (there would be no desert), the clothing culture would have developed differently.

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The high humidity, or sweltering heat, causes irritation.

On a hot day, people evaporate sweat to lower the temperature of the skin, because this does not work well when the humidity is high.

Therefore, the more humid the heat, the higher the discomfort index.

The sensible temperature depends not only on temperature but also on humidity.

The formula for calculating the sensible temperature is very complicated. To put it together at a level that is easy for the general public to understand, the human sensible temperature in summer has the same value as the temperature at 50% humidity, and when the humidity is 10% higher or lower, the sensible temperature is approx. It rises or falls by 1°C.

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For example, when the temperature is 33°C and the humidity is 50%, the sensible temperature is 33°C, but when the humidity is 70%, the sensible temperature rises to 35°C.

Conversely, when the humidity decreases, the perceived temperature also decreases than the temperature.

On the afternoon of the 28th (Thursday), the humidity in the area of ​​Mok-dong, Seoul was only 45%, so the sensible temperature (33.2) was lower than the temperature (34.3 degrees).

Changed 'heat wave' standard: reflect the sensible temperature

The heatwave warning standard originally operated by the Korea Meteorological Agency only reflected the highest daily temperature.

As a result, there was an opinion that the heat wave did not properly reflect the impact on people's health.

This is because even at the same temperature, the level of heat perceived by people varies depending on the level of humidity.

Therefore, the Korea Meteorological Administration is piloting a heat wave warning that reflects the highest “feeling” temperature in a day that people actually feel.

It is from May 2020.

A heat wave warning is when the 'highest daily felt temperature' is 33 degrees or more and it is expected to last for more than 2 days, and a heat wave warning is when the 'highest daily felt temperature' is 35 degrees or more and it is expected to last for 2 days or more. to issue

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Problems arising from 'dry heat - scorching heat'

In the humid heat, the stench of living is also good.

Laundry does not dry well and food spoils more easily.

In the heat of the monsoon season, even people who have a washing machine at home visit a laundromat to run the dryer.

Countries with desert climates are different.

I was in Kabul, Afghanistan, for two weeks in the summer, and when I went to a neighborhood where locals live, I just dumped water after washing dishes in the alley.

It stinks there and it wouldn't be good for public hygiene.

So, is wet heat bad and dry heat good?

I just can't see it that way.

In hot, dry areas, spontaneously igniting wildfires can be a big problem.

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Even in the middle of winter, when Korea is dry, the humidity rarely drops below 40%.

On the other hand, in midsummer in the US and western Canada, the humidity is often lower than the temperature.

This is called a 'temperature-humidity crossover', and fire departments in western North America are very nervous as they see that the possibility of a wildfire in this situation is very high.

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In particular, when the temperature exceeds 30 degrees Celsius and the humidity drops below 30%, a '30-30-30 crossover' occurs when winds reaching 30 km/h per hour occur.

This is because even a small embers can easily spread into a large-scale forest fire, and it will be difficult to catch the fire unless the weather changes.

The sweltering heat with high sensible temperature, the trend of getting worse

It's a big deal, but on our side, the 'severe heat' that catches people is getting worse.

This year, for the first time ever, a tropical night occurred in Seoul in June.

The hot and humid North Pacific high pressure exerts a great influence on the Korean Peninsula in earnest from July to August, as in usual years, because it expanded unusually quickly this year.

August is expected to be warmer than usual.

In the long-term forecast released on July 21, the Korea Meteorological Administration predicted that there is a 50% chance that the temperature will be higher than normal until early to mid-August.

In the graph below, the dotted line is the average temperature level and the solid line is the forecast for next week.

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As global warming accelerates, the position of the North Pacific high pressure is changing, and there is also a study result that the heat actually felt by people on the Korean Peninsula is getting worse.

According to a joint research paper (2021) between the APEC Climate Center and Pusan ​​National University, the intensity of the perceived heat has become much stronger than the increase in temperature since 2010.

As the northwest Pacific subtropical high pressure tends to move southwesterly, hot and humid winds from the southwest sea have pushed more toward the Korean Peninsula, raising the perceived temperature of the Korean Peninsula.

This study analyzed changes in sensible temperature across the Korean Peninsula from 1981 to 2018 in order to understand the complex effects of heat waves on human body and health.

The lead author of the paper, Dr. Hyeon-Joo Lee of the APEC Climate Center, found that the upward trend in the perceived temperature (HPT) during the summer from 1981 to 2018 was much more pronounced than that of the minimum, average, and maximum temperature.

In the graph below, the human-perceived temperature (HPT) at the top represents the summer sensible temperature of the Korean Peninsula, the HPT_Land represents the terrestrial sensible temperature in the 30-40 degree north latitude region similar to the Korean Peninsula, and the actual temperature below it.

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This is interpreted to mean that the intensity of the heat wave felt by people is stronger than the actual temperature increase, and the possibility that the health of the people living on the Korean Peninsula is affected has increased.

According to this paper, the frequency of occurrence of sensible temperature at a 'dangerous' level (feeling 41-54 ℃) with a high possibility of heat-related diseases such as heat stroke has also increased significantly since the 2010s.

The dotted line in the graph below shows the trend.

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Taking a nap in the heat wave (feat. Korea Meteorological Administration 'National Behavior Tips')

According to the National Meteorological Administration's Meteorological Nuri National Action Guidelines, in case of a heat wave, "At work, I maintain personal health by taking a nap of about 10 to 15 minutes during lunch time, etc. with the employees."

In outdoor worksites such as construction sites, it

is recommended to always follow heat safety rules such as water, shade, and rest, and to actively implement the 'heat break time system' especially during vulnerable times (between 2 and 5 pm).

In hot countries such as Spain and Vietnam, there is a culture of taking a nap during the hottest time after lunch and then working more efficiently.

Because not everyone lives with the benefits of air conditioning.

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(Composition/Editing: Hyunsik Lee, D Contents Producer / Content Design: Jisoo Ok)