Kug Jong-Seong

No Thumbnail Available
Last Name
Kug
First Name
Jong-Seong
ORCID
0000-0003-2251-2579

Filters

2022 - 2024 5
5
5
Reset filters

Settings

Search Results

Now showing 1 - 5 of 5
  • Article
    Tropical origins of the record-breaking 2020 summer rainfall extremes in East Asia
    (Nature Research, 2022-03-30) Kim, Sunyong ; Park, Jae-Heung ; Kug, Jong-Seong
    The East Asian countries have experienced heavy rainfalls in boreal summer 2020. Here, we investigate the dynamical processes driving the rainfall extremes in East Asia during July and August. The Indian Ocean basin warming in June can be responsible for the anticyclonic anomalies in the western North Pacific (WNP), which modulate the zonally-elongated rainfalls in East Asia during July through an atmospheric Rossby wave train. In August, the East Asian rainfall increase is also related to the anticyclonic anomalies in the subtropical WNP, although it is located further north. The north tropical Atlantic warming in June partly contributes to the subtropical WNP rainfall decrease in August through a subtropical teleconnection. Then the subtropical WNP rainfall decrease drives the local anticyclonic anomalies that cause the rainfall increase in East Asia during August. The tropical Indian Ocean anomalously warmed in June and the subtropical WNP rainfall decreased in August 2020, which played a role in modulating the WNP anticyclonic anomalies. Therefore, the record-breaking rainfall extremes in East Asia that occurred during summer 2020 can be explained by the teleconnections associated with the tropical origins among the Indian, Pacific, and Atlantic Oceans and their interbasin interactions.
  • Article
    Hysteresis of European summer precipitation under a symmetric CO2 ramp-up and ramp-down pathway
    (IOP Publishing, 2024-06-18) Im, Nari ; Kim, Daehyun ; An, Soon-Il ; Paik, Seungmok ; Kim, Soong-Ki ; Shin, Jongsoo ; Min, Seung-Ki ; Kug, Jong-Seong ; Oh, Hyoeun
    This study investigates the mechanism of the hysteresis of European summer mean precipitation in a CO2 removal (CDR) simulation. The European summer mean precipitation exhibits robust hysteresis in response to the CO2 forcing; after decreasing substantially (∼40%) during the ramp-up period, it shows delayed recovery during the ramp-down period. We found that the precipitation hysteresis over Europe is tied to the hysteresis in the Atlantic Meridional Overturning Circulation (AMOC). During the ramp-down period, an anomalous high surface pressure circulation prevails over Europe. The anomalous high pressure system is a baroclinic response of the atmosphere to strong North Atlantic cooling associated with a weakened AMOC. This anomalous circulation suppresses summertime convective activity over the entire Europe by decreasing near-surface moist enthalpy in Central and Northern Europe while increasing lower free-tropospheric temperature in Southern Europe. Our findings underscore the need to understand complex interactions in the Earth system for reliable future projections of regional precipitation change under CDR scenarios.
  • 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
    Fast reduction of Atlantic SST threatens Europe-wide gross primary productivity under positive and negative CO2 emissions
    (Wiley, 2024-06-01) Yang, Young-Min ; Shin, Jongsoo ; Park, So-Won ; Park, Jae-Heung ; An, Soon-Il ; Kug, Jong-Seong ; Yeh, Sang-Wook ; Lee, June-Yi ; Wang, Bin ; Li, Tim ; Im, Nari
    Climate change mitigation through negative CO2 emissions has been recognized as a crucial strategy to combat global warming. However, its potential effects on terrestrial productivity and agricultural activities remain uncertain. In this study, we utilized large ensemble simulations with an Earth system model of full complexity to investigate the response of Gross Primary Production (GPP) to CO2 forcings. Our findings reveal a significant asymmetry in the GPP response to CO2 ramp-up and symmetric ramp-down model experiments, especially in Europe, suggesting that GPP declines rapidly as CO2 levels decrease. Remarkably, during the CO2 removal period, the North Atlantic Sea surface temperature experienced cooling due to a delayed recovery of the Atlantic Meridional Overturning Circulation (AMOC). This cooling led to precipitation and soil moisture deficits, resulting in a rapid reduction in GPP. This asymmetry in GPP response holds consistent across multi-model simulations. These results underscore the potential implications of delayed recovery in ocean circulation, which could unexpectedly accelerate terrestrial GPP reduction. These insights are crucial for policymakers, aiding them in projecting agricultural activity and formulating targeted GPP control policies specific to the European region.
  • Article
    Deep ocean warming-induced El Niño changes
    (Nature Research, 2024-07-23) Kim, Geon-Il ; Oh, Ji-Hoon ; Shin, Na-Yeon ; An, Soon-Il ; Yeh, Sang-Wook ; Shin, Jongsoo ; Kug, Jong-Seong
    The deep ocean, a vast thermal reservoir, absorbs excess heat under greenhouse warming, which ultimately regulates the Earth’s surface climate. Even if CO2 emissions are successfully reduced, the stored heat will gradually be released, resulting in a particular pattern of ocean warming. Here, we show that deep ocean warming will lead to El Niño-like ocean warming and resultant increased precipitation in the tropical eastern Pacific with southward shift of the intertropical convergence zone. Consequently, the El Niño-Southern Oscillation shifts eastward, intensifying Eastern Pacific El Niño events. In particular, the deep ocean warming could increase convective extreme El Niño events by 40 to 80% relative to the current climate. Our findings suggest that anthropogenic greenhouse warming will have a prolonged impact on El Niño variability through delayed deep ocean warming, even if CO2 stabilization is achieved.