• Atmosphere
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• v.24 no.4
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• pp.555-563
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• 2014

The impacts of dynamic and thermodynamic schemes used in the Community Ice CodE (CICE), the Los Alamos sea ice model, on sea ice concentration, extent and thickness over the Arctic and Antarctic regions are evaluated. Using the six dynamic and thermodynamic schemes such as sea ice strength scheme, conductivity scheme, albedo type, advection scheme, shortwave radiation method, and sea ice thickness distribution approximation, the sensitivity experiments are conducted. It is compared with a control experiment, which is based on the fixed atmospheric and oceanic forcing. For sea ice concentration and extent, it is found that there are remarkable differences between each sensitivity experiment and the control run over the Arctic and Antarctic especially in summer. In contrast, there are little seasonal variations between the experiments for sea ice thickness. In summer, the change of the albedo type has the biggest influence on the Arctic sea ice concentration, and the Antarctic sea ice concentration has a greater sensitivity to not only the albedo type but also advection scheme. The Arctic sea ice thickness is significantly affected by the albedo type and shortwave radiation method, while the Antarctic sea ice thickness is more sensitive to sea ice strength scheme and advection scheme.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.49-54
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• 2016

An active layer distributed on surface of an extreme cold region causes a frost heave by repeating the freezing and thawing according to the seasonal temperature change. Since the height of frost heave is greatly affected by the thickness of active layer, an accurate evaluation of the thickness of active layer is necessary for the safe design and construction of the infrastructure in the extreme cold region. In this study, dynamic cone penetrometer, which is miniaturized in-situ penetration device, is applied for the evaluation of active layer depth distribution. As the application tests, two dynamic cone penetration tests were conducted on the study sites located in Solomon and Alaska. In addition, ground temperature variations were obtained. As the results of the application tests, the depth of interface between the active layer and the permafrost was evaluated from the difference in dynamic cone penetration indexes of the active layer and the permafrost, and a layer was detected around the interface considered as an ice lens layer. Also, the interface depths between the above zero and the below zero temperature determined from the ground temperature variations correspond with the interface depths evaluated from the dynamic cone penetration tests. This study demonstrates that the dynamic cone penetrometer may be a useful tool for the evaluation of the active layer in the extreme cold region.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.77-82
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• 2009

Many countries have been interested in sustainable development of buildings for environmental preservation. Thus it is significant to assess building envelopes in terms of $CO_2$ emissions owing to Kyoto Protocol. In this paper, a Double Skin Facade(DSF) installed in a general office building was assessed by $CO_2$ emissions(one of the performance-based assessment). To predict $CO_2$ emissions caused by the building energy consumption, the dynamic simulation program(Energy Plus) and $CO_2$ emission factor was used. Because DSF has various airflow regimes, pre-simulation runs were conducted to decide proximate optimal airflow regimes depending on seasonal variation. It is shown that the DSF can achieve 17.1-36.5% of annual energy savings.

• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.9-15
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• 2002

This paper presents the seasonal forecasting of the occurrence of tropical cyclone (TC) over Western North Pacific (WNP) using the generalized linear model (GLM) and dynamic linear model (DLM) based on 51-year-data (1951-2001) in TC season (June to November). The numbers of TC and TY are predictands and 16 indices (the E1 Nino/Southern Oscillation, the synoptic factors over East asia and WNP) are considered as potential predictors. With 30-year moving windowing, the estimation and prediction of TC and TY are performed using GLM. If GLM forecasts have some systematic error like a bias, DLM is applied to remove the systematic error in order to improve the accuracy of prediction.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.627-637
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• 2010

Emission rate of monoterpene and isoprene was measured in five commonly growing tree species of conifers(Pinus thunbergii, Abies koreana, Cryptomeria japonica, Pinus densiflora, Chamaecyparis obtusa) at the Halla mountain sites. Dynamic flow enclosure technique was used and gas samples were collected into Tenax tube. The highest and lowest hourly emission rate was observed in Abies koreana (1.86 ${\mu}g$/gdw/hr) and Chamaecyparis obtusa (0.52 ${\mu}g$/gdw/hr), respectively. The major species of monoterpene from pine trees were ${\alpha}$-pinene, ${\beta}$-pinene, ${\beta}$-phellandrene, myrcene. Particularly, d-limonene was abundant in Abies koreana but ${\alpha}$-pinene, $d^3$-carene and sabinene was in Cryptomeria japonica. Emission rates of isoprene show less significant than those of monoterpene. And also seasonal emission rates of monoterpene were dependent on environmental factors such as temperature.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.3
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• pp.298-308
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• 1994

Ocean circulation in the Northeast Pacific Ocean is simulated using a high-resolution primitive equation numerical model with realistic bottom topography. The goal is to explain better the details of observed interannual variability of the circulation in the Gulf of Alaska. Our numerical model suggests that there is no seasonal shift in the Alaska gyre and that the interannual variability. reported earlier, is most likely the result of embedded mesoscale eddies in the dynamic topography. Such eddies have been observed in hydrographic. satellite-tracked drifters and altimeter data from the Gulf of Alaska.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.232-241
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• 2012

We investigated the relationship between vegetation type and soil carbon dynamics in even-aged alder (Alnus hirsuta) and Korean pine (Pinus koraiensis) plantations in central Korea. Both forests were located on the same soil parent material and occupied similar topographic positions. Soil $CO_2$ efflux in the two plantations was determined using a dynamic chamber method accompanied by measurements of soil moisture content and temperature. Mean soil temperature was similar in the two plantations, but mean soil water content was significantly higher in the alder plantation than in the pine plantation. In both plantations, seasonal patterns in soil $CO_2$ efflux exhibited pronounced variation that corresponded to soil temperature. Soil water content did not affect the seasonal variation in soil $CO_2$ efflux. However, in summer, when soil temperature was above $17^{\circ}C$, soil $CO_2$ efflux increased linearly with soil water content in the alder plantation. Estimated $Q_{10}$ was 3.3 for the alder plantation and 2.7 for the pine plantation. Mean soil respiration during the measurement period in the alder plantation was 0.43 g $CO_2\;m^{-2}\;h^{-1}$, which was 1.3 times higher than in the pine plantation (0.33 g $CO_2\;m^{-2}\;h^{-1}$). Higher soil $CO_2$ efflux in the alder plantation might be related to nitrogen availability, particularly the concentration of $NO_3{^-}$, which was measured using the ion-exchange resin bag method.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1291-1298
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• 2010

The aim of this research was to investigate the dynamic changes of the level of total prolactin receptor (PRLR) mRNA and the short form prolactin receptor (S-PRLR) mRNA in skin of cashmere goats from the initiation of cashmere fibre growth to active growth. Eighteen half-sib wethers were allocated randomly to two groups. Melatonin implants were used in order to initiate growth of cashmere fibre before the normal time and reduce blood plasma prolactin (PRL) concentration. Real-time reverse transcription quantitative polymerase chain reaction (real-time PCR) was used to determine PRLR mRNA expression levels of skin from June to November. The results showed that, in Chinese Inner Mongolia cashmere goats, there were seasonal variations in expression of total PRLR mRNA in skin with levels decreasing from June to October. Synchronously, the cashmere fibre growth rate gradually increased during this period, but the expression levels of S-PRLR mRNA did not decrease along with seasonal variation from initiation to active growth of cashmere fibre. These results suggest that expression levels of S- PRLR mRNA might be involved in the process of cashmere growth. It was also possible that the change of alternative splicing of PRLR occurred in the skin of cashmere goats from proanagen to anagen.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.232-241
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• 2012

The seasonal changes in phytoplankton species composition, standing crops, dominant species, species diversity and physico-chemical characteristics in the Unmun dam were studied, from August, 2009 to April, 2010. The phytoplanktons of a total of 121 taxa were identified, the composition of phytoplankton community was characterized by a green algae and diatoms, and the quantity composition of standing crops was dominated by diatoms and dinophyceae. The diatoms Aulacoseria granulata and blue-green alga Anabaena planktonica in Summer, Peridinium voltzii in Autumn and Asterionella formosa in Winter to Spring were, especially, prominent. The seasonal changes of the biomass varied from 578 cells $mL^{-1}$ to 12,938 cells $mL^{-1}$, and the maximum algal density was observed in April, Asterionells formosa contributed to 88% of the total cell numbers. The species diversity and richness were highest during autumn, and dominance index was highest in the spring season.

• Atmosphere
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• v.31 no.5
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• pp.637-656
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• 2021

The United States has been known as the world's major producer of crops such as wheat, corn, and soybeans. Therefore, using meteorological long-term forecast data to project reliable crop yields in the United States is important for planning domestic food policies. The current study is part of an effort to improve the seasonal predictability of regional-scale precipitation across the United States for estimating crop production in the country. For the purpose, a dynamic downscaling method using Weather Research and Forecasting (WRF) model is utilized. The WRF simulation covers the crop-growing period (March to October) during 2000-2020. The initial and lateral boundary conditions of WRF are derived from the Pusan National University Coupled General Circulation Model (PNU CGCM), a participant model of Asia-Pacific Economic Cooperation Climate Center (APCC) Long-Term Multi-Model Ensemble Prediction System. For bias correction of downscaled daily precipitation, empirical quantile mapping (EQM) is applied. The downscaled data set without and with correction are called WRF_UC and WRF_C, respectively. In terms of mean precipitation, the EQM effectively reduces the wet biases over most of the United States and improves the spatial correlation coefficient with observation. The daily precipitation of WRF_C shows the better performance in terms of frequency and extreme precipitation intensity compared to WRF_UC. In addition, WRF_C shows a more reasonable performance in predicting drought frequency according to intensity than WRF_UC.