J.-S. Kug

J.-S. Kug
Pohang University of Science and Technology | POSTECH · School of Environmental Science and Engineering

Ph D

About

348
Publications
107,811
Reads
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17,508
Citations
Additional affiliations
February 2014 - present
Pohang University of Science and Technology
Position
  • Professor (Associate)
December 2008 - February 2014
Korea Institute of Ocean Science and Technology
Position
  • Principal Investigator

Publications

Publications (348)
Article
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The loss of ecosystem carbon (the sum of vegetation, litter, and soil carbon) may occur in a permafrost region under mitigation pathways, which could reduce the efficiency of carbon dioxide removal. Here, we investigate changes in permafrost under net-zero and negative emissions, based on idealized emission-driven simulations using a state-of-the-a...
Preprint
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Existing climate studies mainly assessed the effect of greenhouse gases and aerosols, among other forcings on Earth’s temperature. None of them has not evaluated the effect of the planetary orbital changes on Earth’s temperature. Here, we deconvolved the effects of greenhouse gases and planetary orbital changes on Earth’s temperature and to forecas...
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Enhanced fire-prone weather under greenhouse gas warming can significantly affect local and global carbon budgets from increased fire occurrence, influencing carbon-climate feedbacks. However, the extent to which changes in fire-prone weather and associated carbon emissions can be mitigated by negative emissions remains uncertain. Here, we analyze...
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The 2023–2024 El Niño has raised widespread concern in scientific and public communities. Here, using latest observational reanalysis, we show that this event matured with two distinct spatial peaks of sea surface temperature anomaly in the equatorial central and eastern Pacific, respectively. Like other double-peaked El Niños, the central Pacific...
Preprint
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During an El Niño-decaying summer, the East China Sea (ECS) has experienced anomalous phytoplankton blooming, but the understanding of associated generating mechanisms remains limited. Here, we analyzed observational (25 years) and long-term simulation data (1,000 years) to investigate the underlying mechanisms for the anomalous phytoplankton bloom...
Article
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El Niño-Southern Oscillation (ENSO) is the strongest interannual phenomenon occurring in the tropical Pacific, significantly affecting the entire world. The ENSO response to increasing CO2 concentrations have been extensively studied, but the reverse scenario is still not well understood. Here, we investigate the hysteresis of ENSO teleconnections...
Article
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Sea level rise due to anthropogenic warming threatens coastal environments and human societies, but its regional reversibility under successful climate mitigation efforts remains unclear. Here, we investigate sea level fluctuations in the Subpolar North Atlantic using idealized atmospheric carbon dioxide ramp-up and -down experiments. During the ra...
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The El Niño-Southern Oscillation (ENSO) is a prominent climatological phenomenon in the Pacific Ocean that exerts a significant influence on both physical states and biological activities across the globe through oceanic and atmospheric teleconnections. In this study, we investigate the impact of ENSO on phytoplankton variability in the Western Nor...
Preprint
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Climate change is driving unprecedented changes in terrestrial and marine ecosystems, with profound effects on global atmospheric dynamics, carbon cycling, and productivity 1,2 . In particular, Siberia has experienced an earlier onset of the growing season 3,4,5 and increased productivity ⁴ , contributing to regional warming 4,5,6 and altered aeros...
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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-lik...
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The El Niño–Southern Oscillation (ENSO) provides most of the global seasonal climate forecast skill1–3, yet, quantifying the sources of skilful predictions is a long-standing challenge4–7. Different sources of predictability affect ENSO evolution, leading to distinct global effects. Artificial intelligence forecasts offer promising advancements but...
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Wildfires in Northeast (NE) Siberia have become more frequent owing to the warming climate, exerting a profound impact on the global carbon cycle. While an increase in global temperature is recognized as a primary driver of unprecedented wildfires, the role of precipitation during wildfire season is relatively unexplored. Here, we present evidence...
Article
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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...
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The interdecadal variability of tropical cyclone precipitation (TCP) over the western North Pacific (WNP) has not been thoroughly explored in previous studies. Here, we show that the TCP variations are modulated by both the Atlantic Multidecadal Oscillation (AMO) and Interdecadal Pacific Oscillation (IPO) as evidenced by reanalysis data and model e...
Preprint
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The Atlantic Niño, a primary climatic variability mode in the equatorial Atlantic Ocean, exhibits pronounced variability not only in boreal summer but also in winter. However, the role of Winter Atlantic Niño in trans-basin interactions remains underexplored compared to its summer counterpart. Through analysis of observational reanalysis data since...
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The Indian Ocean Dipole (IOD) has been proposed to be a key driver of biological processes in the Indian Ocean (IO) in the present climate. Given the expected influence of global warming on both the properties of the IOD and the biogeochemistry within the IO, a key question arises: How will the relationship between the IOD and surface chlorophyll e...
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Climate change mitigation through negative CO 2 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...
Article
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The physiological response to increasing CO2 concentrations will lead to land surface warming through a redistribution of the energy balance. As the Amazon is one of the most plant‐rich regions, the increase in surface temperature, caused by plant CO2 physiological forcing, is particularly large compared to other regions. In this study, we analyze...
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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 CO 2 concentrations increase. Here, we show that such changes may not be reversed when...
Article
CMIP6 simulations showed a weak human contribution to 2022-like Central Andes spring droughts, due to compensating impacts between anthropogenic greenhouse gases and aerosols.
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The effects of bio-optical feedback through chlorophyll on future tropical cyclone (TC) activity are not well understood. Here we use Earth system model simulations with the biogeochemical feedback turned on and off to investigate the influence of chlorophyll changes on projections of TCs over the western North Pacific (WNP). An increase in chlorop...
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The Indian Ocean Dipole (IOD) is a major climate variability mode that substantially influences weather extremes and climate patterns worldwide. However, the response of IOD variability to anthropogenic global warming remains highly uncertain. The latest IPCC Sixth Assessment Report concluded that human influences on IOD variability are not robustl...
Article
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El Niño-Southern Oscillation (ENSO) teleconnection to the Euro-Atlantic exhibits strong subseasonal variations, as the North Atlantic Oscillation (NAO) response systematically reverses its phase from early to late winter. Based on two sets of atmospheric model simulations in CMIP6 forced by historical and projected SST, we report a future disappear...
Preprint
Full-text available
Sea level rise (SLR) due to anthropogenic warming poses substantial threats to coastal environments and human societies. Despite successful climate mitigation efforts, regional reversibility of SLR in response to stabilization or reduction of atmospheric carbon dioxide (CO 2 ) remains unclear. Here, we investigate sea level fluctuations in Subpolar...
Article
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In a warming climate, storm tracks are projected to intensify on their poleward side. Here we use large-ensemble CO2 ramp-up and ramp-down simulations to show that these changes are not reversed when CO2 concentrations are reduced. If CO2 is removed from the atmosphere following CO2 increase, the North Atlantic storm track keeps strengthening until...
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The global oceans absorb most of the surplus heat from anthropogenic warming, but it is unclear how this heat accumulation will affect the Earth’s climate under climate mitigation scenarios. Here we show that this stored heat will be released at a much slower rate than its accumulation, resulting in a robust pattern of surface ocean warming and con...
Preprint
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Understanding the carbon cycle is crucial for an accurate assessment of emission allowances, which requires to mitigate climate change within the limits of human tolerance. The oceanic carbon system is an important reservoir for anthropogenic CO 2 emissions, yet uncertainties persist regarding its future changes. Here, we employ the state-of-the-ar...
Preprint
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The global carbon cycle is strongly influenced by terrestrial productivity and the concentration of plankton in the upper ocean, both of which are sensitive to climate variability1–9. It is therefore plausible that plankton bloom-induced marine heatwaves could modify atmospheric circulation, thereby altering weather and climate patterns over adjace...
Article
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The Indian Ocean Dipole (IOD) is a prominent mode of climate variability in the tropical Indian Ocean (IO). It exerts a significant influence on biological activities in this region. To elucidate the biological response to the IOD, previous research has introduced the Biological Dipole Mode Index (BDMI). However, the delineation of the region by th...
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The Madden-Julian Oscillation (MJO) is the dominant mode of tropical intraseasonal variability that interacts with many other Earth system phenomena. The prediction skill of the MJO in many operational models is lower than its potential predictability, partly due to our limited understanding of its predictability source. Here, we investigate the so...
Preprint
Full-text available
El Niño-Southern Oscillation (ENSO) is the strongest interannual phenomenon occurring in tropical Pacific, significantly affecting the entire world. Until now, the response of ENSO to increasing CO 2 concentrations has been extensively studied, but the reverse scenario is still not well comprehended. Here, we investigate the hysteresis of ENSO tele...
Preprint
Full-text available
Climate change mitigation through negative CO2 emissions has been recognized as a crucial strategy to combat global warming. However, its potential effects on terrestrial carbon uptake and agricultural productivity, particularly in Europe, remain uncertain. In this study, we utilized large ensemble simulations with an Earth system model of full com...
Article
Full-text available
Plain Language Summary Human‐induced greenhouse gases are causing the sea‐ice in the Arctic Ocean to decrease. This is making the edges of the sea‐ice retreat poleward to the central Arctic. The Atlantic water, which is warm, salty, and nutrient‐rich, is also expanding northwards. This is causing the Arctic water to become more like Atlantic water,...
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Plain Language Summary El Niño‐Southern Oscillation (ENSO) typically has a dipole impact on tropical cyclone genesis frequency (TCGF) over the western North Pacific (WNP) in the current climate. During the warm phase of ENSO, there is a significant increase in TCGF over the southeastern part of the WNP (open‐sea region), but a decrease over its nor...
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The terrestrial ecosystem in East Asia mainly consists of semi-arid regions that are sensitive to climate change. Therefore, gross primary productivity (GPP) in East Asia could be highly variable and vulnerable to climate change, which can significantly affect the local carbon budget. Here, we examine the spatial and temporal characteristics of GPP...
Preprint
Full-text available
El Niño-Southern Oscillation (ENSO) teleconnection to the Euro-Atlantic exhibits strong subseasonal variations, as the North Atlantic Oscillation (NAO) response systematically reverses its phase from early to late winter. Based on two sets of atmospheric model simulations in CMIP6 forced by historical and projected SST, we report a future disappear...
Preprint
Antarctic meltwater discharge has been largely emphasized for its potential role in climate change mitigation, not only by reducing global warming, but also by stabilizing the Atlantic Meridional Overturning Circulation (AMOC). Despite the tremendous impact of the AMOC on the climate system, its temporal evolution to the meltwater remains poorly un...
Article
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The El Niño-Southern Oscillation (ENSO) influence on the East Asian winter monsoon (EAWM) exhibits remarkable non-stationarity on subseasonal timescales, severely limiting climate predictability. Here, based on observational and reanalysis datasets, we identify a robust subseasonal variability in the EAWM response to ENSO, with a notable synchronou...
Article
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El Niño-Southern Oscillation (ENSO) sea surface temperature (SST) anomaly skewness encapsulates the nonlinear processes of strong ENSO events and affects future climate projections. Yet, its response to CO 2 forcing remains not well understood. Here, we find ENSO skewness hysteresis in a large ensemble CO 2 removal simulation. The positive SST skew...
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Tropical convection plays a key role in regional and global climate variability, and future changes in tropical precipitation under anthropogenic global warming are critical for projecting future changes in regional climate. In this study, by analyzing Coupled Model Intercomparison Project (CMIP) phase 6 models, we show that changes in projected tr...
Article
El Niño-Southern Oscillation (ENSO) is the strongest interannual climate variability with far-reaching socioeconomic consequences. Many studies have investigated ENSO-projected changes under future greenhouse warming, but its responses to plausible mitigation behaviors remain unknown. We show that ENSO sea surface temperature (SST) variability and...
Article
It is important to examine the physical processes that regulate current CO2 concentrations in East Asia to understand the global carbon cycle. To do this, we begin by defining the difference between East Asian and global CO2 concentrations (East Asian CO2 concentration minus global CO2 concentration), which is referred to as East Asian local CO2 co...
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It is known that winter Atlantic-Niño events can induce the El Niño–Southern oscillation (ENSO) in the following winter with a lag of 1-year during one period. On the other hand, summer Atlantic-Niño events can lead to the ENSO in the subsequent winter with a half-year lag during another period. In this study, we investigate the distinct interdecad...
Article
A poleward shift of the Hadley cell (HC) edge in a warming climate, which contributes to the expansion of drought-prone subtropical regions, has been widely documented. The question addressed here is whether this shift is reversible with CO2 removal. By conducting large-ensemble experiments where CO2 concentrations are systematically increased and...
Preprint
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Negative carbon emissions are certainly executed to mitigate global warming, including minimizing the detrimental effects of weather extremes in the future. Here we show that successful implementation of negative emissions significantly increases terrestrial precipitation. Although CO 2 concentrations are reduced by negative emissions, total terres...
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Indian Ocean Dipole phenomenon (IOD) refers to a dominant zonal contrast pattern of sea surface temperature anomaly (SSTA) over tropical Indian Ocean (TIO) on interannual time scales. Its positive phase, characterized by anomalously warm western TIO and anomalously cold southeastern TIO, is usually stronger than its negative phase, namely a positiv...
Article
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El Niño-Southern Oscillation (ENSO) teleconnections exhibit a strong dependency on seasonally and intraseasonally varying mean states, leading to impactful short-term variations in regional climate. The North Atlantic Oscillation (NAO)-ENSO relation is a typical example, in that its phase relationship reverses systematically between the early and l...
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Convective extreme El Niño (CEE) events, characterized by strong convective events in the eastern Pacific, are known to have a direct link to anomalous climate conditions worldwide, and it has been reported that CEE will occur more frequently under greenhouse warming. Here, using a set of CO2 ramp-up and ramp-down ensemble experiments, we show that...
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It has been demonstrated that the increased CO2 concentration would influence El Niño and its connected precipitation anomaly over East Asia (EA). Based on the model simulations from CMIP5 and CMIP6, this study investigates projected change of the boreal winter precipitation anomaly in EA during strong Eastern-Pacific type El Niño (EP-El Niño) resp...
Preprint
In most emissions scenarios consistent with the temperature targets of the Paris Agreement, carbon dioxide removal (CDR) would be required to achieve net negative emissions. The efficiency of CDR depends on the behavior of the natural carbon reservoirs, land and ocean, that regulate atmospheric CO2 concentrations, but their change in response to ne...
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In recent decades, the unprecedented rate of Arctic warming has accelerated the high-latitude landmass hydrological cycle, leading to increased river discharge into the Arctic Ocean. This study elucidates the role of Arctic river discharge, which was the large model uncertainty in the Coupled Model Intercomparison Project 6 (CMIP6), for the phytopl...
Preprint
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The terrestrial ecosystem in East Asia exhibits significant variability in the gross primary productivity (GPP), especially in semi-arid regions that are vulnerable to climate change. This GPP variation significantly modulates the local carbon budget, but our understanding of this and the underlying mechanism is still lacking. Here, we examine the...
Article
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Understanding the impacts of volcanic eruptions on the atmospheric circulations and surface climate in the extratropics is important for inter-annual to decadal climate prediction. Previous studies on the Northern Hemisphere climate responses to volcanic eruptions have shown that volcanic eruptions likely induce northern Eurasian warming through th...
Preprint
Full-text available
The El Niño-Southern Oscillation (ENSO) influence on the East Asian winter monsoon (EAWM) exhibits remarkable non-stationarity on subseasonal timescales, severely limiting climate predictability. Here, based on observational and reanalysis datasets, we identify a robust subseasonal variability in the EAWM response to ENSO, with a notable synchronou...
Article
Full-text available
Plain Language Summary Antarctic sea ice, which affects the Earth's climate system, has gained considerable attention in recent years. Previous studies have shown that the El Nino‐Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) in the tropics affect the sea ice variation in West Antarctica through atmospheric teleconnections at intera...
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As the dominant form of mesoscale variability in the equatorial eastern Pacific, Tropical Instability Waves (TIWs) are known to interact with the El Niño and Southern Oscillation (ENSO) in complex ways. TIWs activity is modulated by the ENSO state and also provide significant feedback on ENSO via nonlinear dynamic heating (NDH), acting as a source...
Article
It is well known that El Niño–Southern Oscillation (ENSO) can influence the East Asian winter climate by modifying the atmospheric circulation over the western North Pacific (WNP). While the impact on precipitation in southeastern China has been extensively studied, the ENSO signal in surface air temperature (SAT) remains overlooked. In this paper,...
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The El Niño–Southern Oscillation (ENSO) significantly affects the wintertime surface climate in western North America (WNA) via the Pacific/North American‐like teleconnection pattern. Here, we show