The Korea Institute of Ocean Science and Technology (KIOST, President Kang Do-hyung) discovered a marine heatwave in the East China Sea, including the southwestern waters of Jeju Island, in 2022 that persisted for 62 days, setting a new record. It attributed the unprecedented heatwave to the 2022 Pakistan floods that led to strong Earth circulation teleconnections.^*

* Teleconnection is a part of the atmospheric wave patterns in the middle latitude of the Northern Hemisphere that is created by internal processes of the Earth’s systems. It is often triggered by the development of convective activity in Pakistan and northwestern India in summer, promoting high-pressure atmospheric circulation in East Asia.

A research team led by Dr. Jeong Jin-yong of KIOST’s Sea Power Enhancement Research Division, along with a research team of Prof. Chu Jeong-eun of City University of Hong Kong, identified the causes of the 2022 marine heatwave in the East China Sea, by phase, under a project titled “Construction of Advanced Ocean Science Base in Jurisdictional Sea Areas and Convergence Research,” which is supported by the Ministry of Oceans and Fisheries.

The research results confirmed that low-salinity water discharged from the Yangtze River was the main cause of the early phase of the marine heatwave, and from the middle phase, air flows formed in the high-pressure belt related to the Earth’s circulation teleconnection pattern played a major role.

* Refer to Figure 1 (Summary of the process of the creation, maintenance, and disappearance of the marine heatwave in the East Chia Sea in 2022).

The research team discovered that the floods in Pakistan in 2022 affected the atmospheric flows, fostered a high-pressure environment over the Korean Peninsula, and created an unusually long-lasting marine heatwave in the East China Sea. The team posted the research results in a thesis.^*

* Oh Hyoeun, Kim Go-un, Jeong Jin-yong, et. al., KIOST, Environmental Research Letters, May 2023 (thesis title: The record-breaking 2022 long-lasting marine heatwaves in the East China Sea)

The average sea temperature in the East China Sea reached a record high of 28.4℃ in July and August of 2022. In June 2022, the volume of low-salinity water from the Yangtze River was the second highest, and the hot, low-salinity fresh water discharged from the river was found to be the main cause of the high temperatures in the East China Sea.

* Refer to Figure 2 (Sea surface temperatures and salinity levels observed at the Ieodo Marine Science Base in 2022).

The research results are based on information collected through simultaneous atmosphere-ocean observations made at the Ieodo Marine Science Base, which was built by KIOST and is operated by the Korea Hydrographic and Oceanographic Agency. The results show that natural disasters caused by climate change, such as the Pakistan floods, could lead to atmosphere-ocean disasters in the waters surrounding the Korean Peninsula due to teleconnections of the Earth’s atmospheric circulation.

As El Nino is likely to cause a significant environmental change in the East China Sea this year, KIOST plans to conduct careful monitoring at the Ieodo Marine Science Base.