[Reading Science] This Summer, the Korean Peninsula Boils Hot

Super El Nino, Ultra-Strong Typhoons, and Rising Sea Temperatures Expected
"Extreme Weather Events Intensified Due to Climate Change"

Super El Ni?o, ultra-powerful typhoons, and Canadian wildfires?extreme weather events driven by climate warming are intensifying, heating up the globe. In particular, the Korean Peninsula is expected to face heavy rains and ultra-powerful typhoons, highlighting the need for preparedness.

What is Super El Ni?o?

El Ni?o refers to the phenomenon where the sea surface temperature in the eastern equatorial Pacific rises by more than 0.5 degrees Celsius above average for over three months. Conversely, when the temperature drops by more than 0.5 degrees, it is called La Ni?a. The so-called Super El Ni?o is not an official term but refers to cases where the temperature rises by more than 2 degrees. The Korea Meteorological Administration (KMA) describes it as a 'very strong El Ni?o.' The occurrence of El Ni?o and La Ni?a is caused by winds. Typically, trade winds (easterlies) blow year-round over the equator, transferring heat energy and seawater from the eastern Pacific to the western Pacific. This causes upwelling of cold deep seawater in the eastern Pacific, making its sea surface temperature relatively lower than that of the western Pacific. However, sometimes the trade winds weaken temporarily due to factors like temperature and pressure changes. At this time, warm seawater from the western Pacific flows into the eastern Pacific, raising the sea surface temperature and causing the El Ni?o phenomenon. Conversely, when trade winds strengthen, the upwelling of cold seawater intensifies, lowering the sea surface temperature and causing La Ni?a.

▲El Ni?o occurs when sea surface temperatures in the tropical Pacific Ocean rise abnormally. [Photo by NASA]

The Korea Meteorological Administration issued an El Ni?o advisory on the 23rd of last month. This was because the sea surface temperature in the eastern Pacific measured on May 14-15 was 28.5 degrees Celsius, 0.5 degrees higher than the average. Accordingly, the KMA forecasted that the sea surface temperature would gradually rise from June to August, increasing the likelihood of El Ni?o occurrence. These El Ni?o and La Ni?a phenomena have occurred periodically over several months to years. The problem is that due to global warming and other factors, the overall weather environment is changing and becoming more extreme.

Myung-In Lee, director of the Heatwave Research Center at Ulsan National Institute of Science and Technology (UNIST), said, "Originally, El Ni?o and La Ni?a phenomena have been effective means of transferring heat energy from low latitudes to mid-latitudes," adding, "The occurrence of a Super El Ni?o indicates that the Earth's atmospheric conditions have deviated from normal, increasing the risk of extreme heatwaves and heavy rains, such as the heatwave that occurred in Spain last April."

[Image source=Yonhap News]

On the Korean Peninsula, beware of heavy rains and 'monster-class typhoons'

If El Ni?o occurs, the rainy season starting at the end of this month on the Korean Peninsula is expected to be prolonged, with more rainfall and hotter, more humid weather than usual. When the sea surface temperature in the eastern Pacific rises, the air also warms, causing it to rise and expand, leading to low pressure, while relatively high pressure is more likely to form in the western Pacific. This results in the formation of the warm and humid 'North Pacific High' over the seas near Guam and the Philippines. The Korean Peninsula lies on the edge of this North Pacific High, resulting in hot and humid weather with frequent rainfall. Therefore, the possibility of extreme and prolonged heatwaves like those lasting over two months in 2013 is low.

However, caution is needed for heavy rains and ultra-powerful typhoons. During El Ni?o periods, the number of typhoons hitting the Korean Peninsula tends to decrease, but their intensity tends to increase. A 2013 study examining typhoons from 1951 to 2010 found that 23.9 typhoons occurred in El Ni?o years, fewer than the 24.9 during La Ni?a years. However, the average central minimum pressure and maximum wind speed, indicators of typhoon intensity, were 959.3 hPa and 35.8 m/s during El Ni?o years, stronger than 965.5 hPa and 33.7 m/s during La Ni?a years, and the overall average of 962.3 hPa and 35.0 m/s.

Director Lee warned, "Typhoons during El Ni?o periods form far out at sea, allowing them to absorb sufficient moisture without resistance from mountain ranges or terrain, giving them enough time to mature and become much stronger. Although they mostly track toward Japan, if they come to Korea, the risk of large-scale disasters is high."

Heated Oceans

The oceans are also boiling. The National Institute of Fisheries Science forecasted on the 30th of last month that sea temperatures in Korean waters this summer will be 0.5 to 1.0 degrees Celsius higher than average. In particular, the likelihood of Marine Heatwaves is expected to be high. Already, the average sea temperature in Korean waters this year has been 1 to 3 degrees higher than usual. This is due to very strong warm currents flowing from low latitudes and the end of La Ni?a, which has caused atmospheric circulation changes that continuously supply heat energy from equatorial regions, maintaining high sea temperatures. The U.S. National Oceanic and Atmospheric Administration (NOAA) also forecasted a 60-70% probability of Marine Heatwaves occurring in Korean waters, including the East Sea, during summer.