• Journal of Climate Change Research
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• v.34 no.15
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• pp.6335-6353
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• 2021

This study examines the temporal evolution of the extratropically forced tropical response in an idealized aquaplanet model under equinox condition. We apply a surface thermal forcing in the northern extratropics that oscillates periodically in time. It is shown that tropical precipitation is unaltered by sufficiently high-frequency extratropical forcing. This sensitivity to the extratropical forcing periodicity arises from the critical time required for sea surface temperature (SST) adjustment. Low-frequency extratropical forcing grants sufficient time for atmospheric transient eddies to diffuse moist static energy to perturb the midlatitude SSTs outside the forcing region, as demonstrated by a one-dimensional energy balance model with a fixed diffusivity. As the transient eddies weaken in the subtropics, a further equatorward advection is accomplished by the Hadley circulation. The essential role of Hadley cell advection in connecting the subtropical signal to the equatorial region is supported by an idealized thermodynamical-advective model. Associated with the SST changes in the tropics is a meridional shift of the intertropical convergence zone. Since the time needed for SST adjustment increases with increasing mixed layer depth, the critical forcing period at which the extratropical forcing can affect the tropics scales linearly with the mixed layer depth. Our results highlight the important role of decadal-and-longer extratropical climate variability in shaping the tropical climate system. We also raise the possibility that the transient behavior of a tropical response forced by extratropical variability may be strongly dependent on cloud radiative effects.

• Journal of Climate Change Research
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• v.34 no.22
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• pp.8829-8840
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• 2021

Recent studies have highlighted that a primary mechanism of the East Asian summer monsoon (EASM) is the fluid dynamical response to the Tibetan Plateau (TP), that is, orographically forced Rossby waves. With this mechanism in mind, this study explores how changes in the location of the TP affect the EASM precipitation. Specifically, the TP is moved in the four cardinal directions using idealized general circulation model experiments. The results show that the monsoon aspects are entirely determined by the location of the TP. Interestingly, the strongest EASM precipitation occurs when the TP is situated near its current location, a situation in which downstream southerlies are well developed from the surface to aloft. However, southerlies into the EASM region weaken as the TP moves, which in turn reduces the precipitation. Nevertheless, as long as it moves in the east-west direction, the TP is likely to force the stationary waves that induce precipitation over the midlatitudes (not necessarily over East Asia). In contrast, moving the TP well north of its original location does not induce strong monsoon flows over the EASM region, resulting in the driest case. Meanwhile, although the southward movement of the TP triggers downstream southerlies to some extent, it does not lead to an increase in the precipitation. Overall, these results show that the location of the TP is crucial in determining the EASM precipitation, and the latter is much more sensitive to the displacement of the TP in the meridional direction than in the zonal direction.

• Journal of the Korean Geophysical Society
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• v.9 no.1
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• pp.27-36
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• 2006

The radiative convective equilibrium (RCE) temperature was calculated for the climate change study at King Sejong Station in West Antarctica. As a result of RCE model sensitivity test, the increases of surface albedo, solar zenith angle, and cloud optical thickness decrease surface temperature. On the other hand, the increases of carbon dioxide and cirrus cloud amount are caused by surface warming due to the greenhouse effect. According to the model calculation result, annual mean surface temperature shows a upward trend of 0.012oC/year during the period of 1958-2001. During the period of 1989∼2001, the trend of monthly mean surface temperature by model calculation is 0.01oC/month and the observation trend is 0.005oC/month.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.65-71
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• 2009

In this study, performance and economic analysis of natural gas/syngas fueled 100 MWth chemical-looping combustion (CLC) combined cycle plant were performed. Net efficiency of both cases was 53~54%, corresponding to previous research. We used Chemical Engineering Plant Cost Index and Guthrie method to evaluate plant cost. For syngas fueled CLC combined cycle plant, the plant cost was higher since lower heating value(LHV) of syngas was lower than that of natural gas and cost of electricity(COE) was also higher since the cost of syngas was higher than that of natural gas. By sensitivity analysis, it was shown that the cost of syngas should be less than 5.3 $/GJ in order to make COE lower than 5.8 ¢/kWh which was COE of natural gas fueled CLC combined cycle plant.

• Journal of the Korean Society of Costume
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• v.66 no.6
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• pp.110-121
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• 2016

The purpose of this study is to develop high value-added uniform design in response to climate change, and produce high sensitivity uniforms that conserve the energy of its wearers. The scope of the study encompassed entire production stage from the product planning stage to developing a prototype to collecting consumer ratings to securing intellectual property. The results of the study are as follows. First, the material was developed that maximizes insulation by replicating human body heat radiation and raising the temperature by 5 degree Celsius. Second, through Time to Market system, a luxurious synthetic wool material was developed, and warm effect was achieved. Third, pattern design engineering for easy movement and design development allowed the realization of uniform design that is compatible indoors and outdoors as well as respond to highly active climate change. Fourth, Fifth, the developed design was registered and intellectual property rights were obtained.

• Environmental and Resource Economics Review
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• v.26 no.3
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• pp.359-398
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• 2017

Uncertainty is central to energy and climate policy. A growing number of literature show that almost all components of energy and climate models are, to some extent, uncertain and that the effect of uncertainty on the model outputs, in turn policy recommendations, is significantly large. Most existing energy and climate-economy models developed and used in Korea, however, do not take uncertainty into account explicitly. Rather, many models conduct a deterministic analysis or do a simple (limited) sensitivity analysis. In order to help social planners to make more robust decisions (across various plausible situations) on energy and climate change issues, an uncertainty analysis should be conducted. As a first step, this paper reviews the theory of decision making under uncertainty and the method for addressing uncertainty of existing probabilistic energy and climate-economy models. In addition, the paper proposes a strategy to apply an uncertainty analysis to energy and climate-economy models used in Korea. Applying the uncertainty analysis techniques, this paper revises the FUND model and investigates the impacts of climate change in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.711-716
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• 2012

Due to the climate change in South Korea the annual total precipitation will increase by 17 percent by 2100. Rainfall is concentrated during the summer in South Korea and the landslide of farmland by heavy rain is expected to increase. Because regional torrential rains accompanied by a storm continue to cause the damage in farmland urgent establishment of adaptation plant for minimizing the damage is in need. In this study we assessed vulnerability of landslide of farmland by heavy rain for local governments. Temporal resolution is 2000 year and the future 2020 year, 2050 year, 2100 year via A1B scenario. Vulnerability of local government were evaluated by three indices such as climate exposure, sensitivity, adaptive capacity and each index is calculated by selected alternative variable. Collected data was normalized and then multiplied by weight value that was elicited in delphi investigation. Current vulnerability is concentrated in Jeju island and Gyeongsangnam-do, however, it is postulated that Kangwon-do will be vulnerable in the future. Through this study, local governments can use the data to establish adaptation plans for farmland landslide by climate change.

• Journal of the Korean Geographical Society
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• v.49 no.4
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• pp.489-508
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• 2014

The purpose of this study is to clarify the spatio-temporal patterns of changes in seasonal extreme temperature events in the Republic of Korea based on daily maximum and minimum temperature data sets observed at 61 weather stations for the recent 40 year period (1973~2012). According to analysis of regional average data, in spring increases of warm days are most distinct, while in summer reductions of cool nights and increases of warm nights are most noticeable. The similar patterns to those in summer are observed in fall, while in winter reductions of cool days and nights are notable. Regardless of the magnitude of urbanization, changes in nighttime extreme temperature events prevail in transitional periods between seasons, while those in daytime extreme temperature events do so only in particular months. In contrast, cool days in spring and summer, warm days in summer and warm nights in winter do not show any statistically-significant changes at most of stations. The sensitivity of seasonal extreme temperature events to increases of seasonal average extreme temperature is greatest in the case of warm days ($+6.3days/^{\circ}C$) and cool nights ($-6.2days/^{\circ}C$) in spring, warm nights ($+10.4days/^{\circ}C$) and days ($+9.5days/^{\circ}C$) in summer, warm days ($+7.7days/^{\circ}C$) in fall, and cool nights ($-4.7/^{\circ}C$) in winter, respectively. These results indicate that changes in seasonal extreme temperature events and their sensitivity to changes in seasonal climate means under a warmer climate are occurring with seasonally and diurnally asymmetric magnitudes in Korea due to complex climate feedbacks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.508-516
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• 2021

Although scientist have been reporting recently that changes in ocean environment influence the species composition, movements, and growth of fish in Korea waters. Previous studies on fish vulnerability owing to climate changes are insufficient to explain the effect of fluctuating ocean environments on fisheries ground. In this study, we suggested a method for the assessment of fisheries sensitivity to various factors in ocean environments in Korean waters. To evaluate the fisheries sensitivity, catch data (Chub mackerel, Hairtail, Common squid, small yellow croaker) from National federation of fisheries cooperatives in Korea (1991-2017) and oceanographic data from Korea Ocean Data Center (KODC; 1960-2017) were normalized using the z-score method. Thereafter, the fisheries sensitivity was calculated using the difference between the catch data and the oceanographic data. Finally, the fisheries sensitivity was evaluated based on evaluation grade ratings. Result revealed that in the south sea, variability in catch data was obviously higher than environmental fluctuation (evaluation grade 1), indicating that catch variability in response to environmental change is most sensitive in the south sea among Korean waters in 2017. These results would be helpful for fishery management and policy for sustainable yield in Korean waters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.43-54
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• 2023

Due to climate change, drought and flood occurrences have been increasing. Accurate projections of watershed discharges are imperative to effectively manage natural disasters caused by climate change. However, climate change and hydrological model uncertainty can lead to imprecise analysis. To address this issues, we used two lumped models, IHACRES and GR4J, to compare and analyze the changes in discharges under climate stress scenarios. The Hapcheon and Seomjingang dam basins were the study site, and the Nash-Sutcliffe efficiency (NSE) and the Kling-Gupta efficiency (KGE) were used for parameter optimizations. Twenty years of discharge, precipitation, and temperature (1995-2014) data were used and divided into training and testing data sets with a 70/30 split. The accuracies of the modeled results were relatively high during the training and testing periods (NSE>0.74, KGE>0.75), indicating that both models could reproduce the previously observed discharges. To explore the impacts of climate change on modeled discharges, we developed climate stress scenarios by changing precipitation from -50 % to +50 % by 1 % and temperature from 0 ℃ to 8 ℃ by 0.1 ℃ based on two decades of weather data, which resulted in 8,181 climate stress scenarios. We analyzed the yearly maximum, abundant, and ordinary discharges projected by the two lumped models. We found that the trends of the maximum and abundant discharges modeled by IHACRES and GR4J became pronounced as changes in precipitation and temperature increased. The opposite was true for the case of ordinary water levels. Our study demonstrated that the quantitative evaluations of the model uncertainty were important to reduce the impacts of climate change on water resources.