• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.127-136
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• 1998

To use the earth heat for the livestock housing, an underground heat exchanger is developed and pipes are layed in the depth of 2.5m under the ground. The pipes have two different kinds of diameter (200mm, 100mm) and materials (PE, PVC). The results of heating effect in winter and spring are following. The temperature in different soil depth varies from 5$^{\circ}C$ by 1.5m depth, to 9$^{\circ}C$ by 3.5m. So it should be better to have the depth greater than 2.5m. The difference of air temperature between the inside and outside pipe was 9.9 Kelvin(K) with 200mm diameter and 13.4K with the 100mm diameter with the same material in winter. By the lower outside temperature from -7.2$^{\circ}C$, it could keep the air temperature above 6$^{\circ}C$ through the 100mm diameter pipe. The heating performance was 593 W with 200mm diameter, 118W with 100mm diameter (PE), and 115W with 100m diameter (PVC), respectively. As the outside temperature varies from -1.5$^{\circ}C$ to 18.6$^{\circ}C$ in early spring, the air temperature through the pipes show 4∼8$^{\circ}C$. While the difference between maximum and minimum outside temperature is 14K, the one through the pipes could be reduced by 2K. Pipes with small diameter can more reduce the difference than the pipe with larger diameter.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.4
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• pp.83-91
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• 2010

Generally, the GCM (General Circulation Model) data by IPCC climate change scenarios are used for future weather prediction. IPCC GCM models predict well for the continental scale, but is not good for the regional scale. This paper tried to generate future temperature and precipitation of 8 scattered meteorological stations in South Korea by using the MIROC3.2 hires GCM data and applying LARS-WG downscaling method. The MIROC3.2 A1B scenario data were adopted because it has the similar pattern comparing with the observed data (1977-2006) among the scenarios. The results showed that both the future precipitation and temperature increased. The 2080s annual temperature increased $3.8{\sim}5.0^{\circ}C$. Especially the future temperature increased up to $4.5{\sim}7.8^{\circ}C$ in winter period (December-February). The future annual precipitation of 2020s, 2050s, and 2080s increased 17.5 %, 27.5 %, and 39.0 % respectively. From the trend analysis for the future projected results, the above middle region of South Korea showed a statistical significance for winter precipitation and south region for summer rainfall.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.11-12
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• 2017

This study aims to analyze the properties of the temperature change in vertical reinforcements in outdoor wall structures in winter in relation to the different methods of bubble sheet installation, and to subsequently determine the possibility of initial frost damage to the concrete as a result of low temperature. As for the experimental variables, double bubble sheets were used as curing materials, and the curing method was to model the part where the slab and the wall intersect and the rebar is exposed, and to measure the change of temperature around the exposed rebar in accordance with the change of the coating curing. It was found that by employing curing method B, which is to install the bubble sheet between the vertical reinforcements, the most vulnerable area, which is 50mm below(④) the surface of the concrete, would be lowered to sub-zero temperature 20 hours later than when using curing method A, and that therefore it is more effective to install the bubble sheet between the vertical reinforcements for the prevention of initial frost damage.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1183-1189
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• 2009

The sedimentation rate of particles in a suspension is a function of particle size, initial slurry water content and salinity. Many researches conducted on the behavior of dredged soils have centered on such factors. However, there have been few attempts to assess another important influence factor of seasonal water temperature on designing the placement of dredged materials. In this paper, the effect of seasonal water temperature on sedimentation characteristics of dredged clay was investigated with consideration of three different water temperatures, that are $5^{\circ}C$, $15^{\circ}C$, $35^{\circ}C$, which represent critical water temperatures in winter, spring or fall, and summer, respectively. A series of experimental results reveal that the sedimentation rates for the water temperature of $15^{\circ}C$ and $35^{\circ}C$ are very similar each other, but that of $5^{\circ}C$ that represents a winter season leads to a considerably delayed sedimentation compared to the others. This may be attributable to the retardation of ion-leaching from clay particles at low water temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1154-1160
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• 2015

This paper describes the thermal characteristics of underground power cable system terminations according to the change of ambient temperature as well as operating temperature. Recently, the failure has been gradually increasing in outdoor termination during winter season because the power demand was increased by electricity heating system. The power demand and outdoor temperature is difference between day time and night time. The temperature difference has an influence on conductor extension and shrinkage due to conductor force as well as thermal mechanical characteristics. These phenomena have daily repeated during heating and cooling period of conductors. In these cases, the insulation of outdoor terminations might be degraded by the reduced interface pressure surrounding stress relief cone. Therefore, in this paper, the thermal characteristics are variously analysed by simulation considering power demand and ambient temperature condition during winter season at epoxy type termination as well as slip-on type termination

• Korean Journal of Human Ecology
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• v.19 no.4
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• pp.745-760
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• 2010

The purposes of this study were to investigate the state of indoor thermal and air environment during winter in the one-room type multi-family houses occupied by university students and to analyze factors which influenced this environment. Field survey was conducted in 10 houses between 30th January, 2009 and 13th February, 2009 which measured indoor thermal and air elements as well kept records of interviews with residents and other related factors. Measured elements were air temperature, relative humidity, as well as concentrations of $CO_2$, CO, TVOC, and PM-10. The results can be summarized as follows. 1) The mean air temperature in each house ranged from 19.3 to $25.3^{\circ}C$, so most houses were not suitable for evaluation criteria($20-22^{\circ}C$). The average $CO_2$ concentration in each house was 965~3259ppm, so most houses exceeded evaluation criteria(1000ppm). The average TVOC concentration in each house were 0.00~1.17ppm, 5 houses exceeded evaluation criteria(0.12ppm). 2) Relative humidity, CO concentration, and PM-10 concentration were suitable for evaluation criteria. Therefore, indoor thermal and air environment during winter in one-room type multi-family housing occupied by university students was found to be generally uncomfortable. Important factor which were found to influence air temperature and the concentration of $CO_2$ were smaller space capacity than general house. Other factors which were found to influence the environment of these houses were the existence of a balcony as well as factors relating to the behavior of occupants such whether or not heating were operated, whether windows were opened, whether fans used, whether occupants smoked or used cosmetics, and whether the space was dusted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.111-116
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• 1983

Temperature inversions are investigated by using the oceanographic data (1965-1979) obtained in the Southern Sea of Korea. The temperature inversions in winter occur about six times more frequently than those in sumner. In the west region of the Southern Sea, the inversions are found at any depth in winter. In the east region of the Southern Sea, however, they usually appear in surface layer in winter. Such inversion phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the sea surface and a southward advection of surface cold water due to north-westerly monsoon. In summer the inversion layers are usually formed below the thermocline in the west region of the Southern Sea, and in surface layer in the east region. The former results from the mixing between the Tsushima Warm Current and the Yellow Sea Bottom Cold Water, and the latter is generated by an offshore flow of cold water near coast due to southwesterly wind.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.99-108
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• 2016

The shuttle breeding of Korean winter wheat has been able to develop high-yielding and day-length-intensive varieties with a wide range of ecologic adoption. However, the phenology of winter wheat has been changed due to recent rises in the winter temperature of Toluca and increasing frequency of high temperatures. We defined two wheat groups (group II and III) with vernalization and evaluated the impact of cold exposure duration and heading ratio due to changes in sowing dates by measuring changes in cold exposure duration and corresponding heading states of each group. The wheat cultivars were sown on three dates in two years. The cold exposure requirement of wheat sown on 6 November 2013 was unfulfilled. The cold exposure requirement of wheat sown on 22 November and 6 December 2013 was fulfilled. However, in 2014, the cold exposure requirement of wheat sown on 5 and 20 November was fulfilled, but that of wheat sown on 5 December was unfulfilled. The differences for the two early November sowings were because winter temperature rises, which caused high temperatures in 2013, whereas early November 2014 saw normal temperatures for the area. The heading ratio of group II did not show a clear difference among the three sowing dates, while the heading ratio of group III was reduced by about half. This implies that the efficiency of shuttle breeding of group III will be high since it showed strong sensitivity to changes in sowing dates. We calculated future sowing dates of each group under near future climate scenarios; the future available sowing dates of group II were projected, but the dates of group III were never estimated in the temperature rise scenario in Toluca. Our findings suggest that change of sowing dates should be considered in the strategy for shuttle breeding of Korean winter wheat.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.43-48
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• 2001

Chlorophyll fluorescence of needles of Korean fir (Abies koreana) plants and environmental factors of their natural habitat were investigated in order to obtain the information for environmental adaptation and conservation of Korean fir plants. The photochemical efficiency of photosystem II, Fv/Fm, of Korean fir needles was significantly low (0.19-0.36) in the winter, whereas it was high (0.8-0.86) in the summer. The Fv/Fm value of the winter was slightly higher at mid-day than at dawn, suggesting that mid-day environmental conditions of the winter were favorable on needles of Korean fir plants. In contrast, the mid-day Fv/Fm value of the summer maintained high (around 0.8). It indicates that mid-day environmental conditions of the summer did not induce photodamage, although it caused a slight decrease in the Fv/Fm values. The non-photochemical fluorescence quenching (NPQ) of Korean fir needles was very low (0-0.01) all through the day in the winter. However, it was high (0.76) at mid-day in the summer. These results suggest that Korean fir plants have a system for the protection of PS II from mid-day environmental stresses of the summer. In the winter, the Fv/Fm values were positively correlated with temperature, light intensity and relative humidity, although NPQ values showed no correlation with any of them. In the summer, the Fv/Fm values were positively correlated with relative humidity but negatively correlated with temperature and light intensity. These results indicate that increase of tempera-ture, light intensity and relative humidity lead to promotion of the photochemical efficiency in the winter and high temperature and light intensity may cause photoinhibition in the summer.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.747-754
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• 2003

The actual clothing conditions were surveyed to diagnose clothing condition of Korean female in the view point of the adaptation to the thermal environment according to seasonal changes. Then, clothing microclimate, physiological responses, and subjective sensation were investigated through wearing trials on human body in climatic chamber based on the results from the survey. Factors to evaluate validity of clothing condition were clothing weight, clothing microclimate, physiological response of human body, and subjective sensation. The results were as follows: 1. Clothing weight per body surface area of the season was $856g/m^{2}$, $439g/m^{2}$ in summer, $630g/m^{2}$ in fall, and $1184g/m^{2}$ in winter. Cold - resistance of Korean female in office was superior to Japanese, inferior to residents of rural areas of Korea, and similar to male in office. However, in heat - resistance, female in office was inferior to residents of rural areas of Korea. 2. In spring, fall, winter, clothing microclimate temperature was a little higher than that in summer. Therefore, it was not a desirable wearing condition even though the clothing microclimate was comfortable zone. 3. Mean skin temperature of female in office was including within the range of Winslow's comfortable zone, but the range of comfortable zone in mean skin temperature of female was more narrow than Winslow's. Thus, it has problem for female to adaptation to thermal environment.