Physical Oceanography (PO)

Permanent URI for this collection

https://hdl.handle.net/1912/7

Department members investigate the dynamics and thermodynamics of ocean circulation. They work globally from the Arctic to the Antarctic and from the Strait of Gibraltar to the Philippine shelf on the full range of oceanic processes, from mixing on centimeter scales to heat balance on the global scale.

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Browsing Physical Oceanography (PO) by Author "An, Soon-Il"
  • Article
    Basin-dependent response of Northern Hemisphere winter blocking frequency to CO2 removal
    (Nature Research, 2024-05-23) Hwang, Jaeyoung ; Son, Seok-Woo ; Martineau, Patrick ; Sung, Mi-Kyung ; Barriopedro, David ; An, Soon-Il ; Yeh, Sang-Wook ; Min, Seung-Ki ; Kug, Jong-Seong ; Shin, Jongsoo
    Atmospheric blocking has been identified as one of the key elements of the extratropical atmospheric variabilities, controlling extreme weather events in mid-latitudes. Future projections indicate that Northern Hemisphere winter blocking frequency may decrease as CO2 concentrations increase. Here, we show that such changes may not be reversed when CO2 concentrations return to the current levels. Blocking frequency instead exhibits basin-dependent changes in response to CO2 removal. While the North Atlantic blocking frequency recovers gradually from the CO2-induced eastward shift, the North Pacific blocking frequency under the CO2 removal remains lower than its initial state. These basin-dependent blocking frequency changes result from background flow changes and their interactions with high-frequency eddies. Both high-frequency eddy and background flow changes determine North Atlantic blocking changes, whereas high-frequency eddy changes dominate the slow recovery of North Pacific blocking. Our results indicate that blocking-related extreme events in the Northern Hemisphere winter may not monotonically respond to CO2 removal.
  • Article
    Ocean fronts as decadal thermostats modulating continental warming hiatus
    (Nature Research, 2023-11-27) Sung, Mi-Kyung ; An, Soon-Il ; Shin, Jongsoo ; Park, Jae-Heung ; Yang, Young-Min ; Kim, Hyo-Jeong ; Chang, Minhee
    Over the past decade, an unexpected cooling trend has been observed in East Asia and North America during winter. Climate model simulations suggest that this pattern of stalled warming, besides accelerated warming, will repeat throughout the course of global warming, influenced by the natural decade-long variations in the climate system. However, understanding the exact factors affecting the pace of warming remains a challenge. Here we show that a pause in warming over continental areas—namely, local warming hiatus—can be accompanied by excessive heat accumulation north of the ocean fronts. This oceanic condition, often manifesting in the form of marine heatwaves, constrains the subseasonal growth of atmospheric planetary waves, significantly increasing the likelihood of cold extremes in downstream continents. Our results underscore the importance of closely monitoring changing ocean fronts in response to human-induced warming, which can potentially reshape the inherent decade-long fluctuations within regional climates over the long term.