• Atmosphere
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• v.22 no.2
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• pp.187-197
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• 2012

This study investigates the relationship between the Korean temperature and the atmospheric circulation such as Arctic Oscillation, Siberian High and Aleutian Low during the winter (December-January) for the period of 1970-2011. It is found that all indices to represent aforementioned circulations are significantly correlated with Korean winter temperature for the period of 1970 - 2011. There are marked contrasts in such relationship, however, before and after the mid-1980s when a significant regime shift of Korean winter temperature occurred. While Korean winter temperature has a close relationship with Arctic Oscillation after the mid-1980s, its relationship with Siberian High and Aleutian Low is weakened. The composite analysis between a positive and negative phase of Arctic Oscillation before and after the mid-1980s is conducted to examine a recent strengthening of Arctic Oscillation-Korean winter temperature relationship. It is found that the structural changes of low-level wind and the geopotential height at 500 hPa between the two phases of Arctic Oscillation are more effective to influence Korean winter temperature after the mid-1980s. This may induce a close relationship between the Korean winter temperature variability and Arctic Oscillation after the mid-1980s compared to before the mid-1980s.

• Journal of Climate Change Research
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• v.6 no.2
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• pp.87-94
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• 2015

To compare changes in winter temperature over South Korea, 30-year average climate data and climate data of recent 10 years (2014~2014) such as mean temperature, daily maximum temperature and daily minimum temperature were analyzed. Also, we set analysis extreme cold waves frequency related to winter such as freezing days, snow days, days with temperature of below -5, and days with temperature of below -10. This process enabled the comparative analysis of winter temperature changes and extreme cold waves frequency related to winter. This study estimated that winter temperature has gradually increased throughout the last five decades, however, the frequency of extreme weather, such as cold waves has also increased.

• The Korean Journal of Community Living Science
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• v.21 no.4
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• pp.633-639
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• 2010

This study was carried out to compare human thermoregulatory responses and preferred air temperature by feet immersion between summer and winter in terms of thermal comfort. Five healthy female university students participated in the study as subjects. They experienced feet immersion at $40^{\circ}C$ of water in the climatic chamber of $24^{\circ}C$, 50%RH from 19:30 to 21:00 in the summer and winter, respectively. Rectal temperature gradually decreased and maintained $0.08^{\circ}C$ lower in winter than summer, while mean skin temperature changed $0.4^{\circ}C$ greater in winter than summer(p=0.00). Air temperature selected by each subject for their thermal comfort revealed $0.8^{\circ}C$ higher in summer than winter(p=0.06). The results obtained suggest an increase in human thermoregulation and be used as preliminary data to maintain optimal indoor temperature in summer and winter.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1425-1433
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• 2012

Water temperature in the eastern part of the Yellow Sea (EYS) during winter (JFM) and summer (JJA) from 1964 to 2009 and Siberian High Pressure Index (SHI) and Arctic Oscillation index (AOI) during winter (JFM) from 1950 to 2011 were used to analyze long-term variation in oceanic and atmospheric conditions and relationship between winter and summer bottom water temperature. Winter water temperature at 0, 30 and 50 m had fluctuated highly till the late of 1980s, but after this it was relatively stable. The long-term trends in winter water temperature at both depths were separated with cold regime and warm regime on the basis of the late 1980s. Winter water temperature at 0m and 50m during warm regime increased about $0.9^{\circ}C$ and $1.1^{\circ}C$ respectively compared to that during cold regime. Fluctuation pattern in winter water temperature matched well with SHI and AOI The SHI had negative correlation with water temperature at 0 m (r=-0.51) and 50 m (r=-0.58). On the other hand, the AO had positive correlation with Winter water temperature at 0 m (r=0.34) and 50 m (r=0.45). Cyclic fluctuation pattern of winter water temperature had a relation with SHI and AO, in particular two to six-year periodicity were dominant from the early of the 1970s to the early of the 1980s. Before the late of 1980s, change pattern in winter water temperature at 0 and 50 m was similar with that in the bottom water temperature during summer, but after this, relationship between two variables was low.

• Atmosphere
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• v.29 no.5
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• pp.599-607
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• 2019

The change and periodicity of Korean winter temperature in the period 1979-2018 are investigated. It is shown that the winter temperature is on a long-term rise, with two regime shifts of winter temperature during 40 years. In addition, the decrease in cold days is confirmed along with the rise in temperature. Analysis of the periodicity of daily temperature in winter is carried out by means of power spectral analysis. Of the spectral peaks that are statistically significant, the most frequent detection exists on the time scale between 7 and 8 days. It is found that the number of significant periods have decreased since 2014, particularly no longer existent around the period of 7 day. The longer periods than 7 days gradually increase during 40 years, while the shorter periods show the tendency of decrease but recently rebound. Spectral analysis calculated from high/low-pass filtered daily temperature data also shows similar results.

• Journal of Biosystems Engineering
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• v.30 no.3 s.110
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• pp.155-160
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• 2005

The objective of this research was to establish a domestically available cooling storage technique by cold-air in winter, using winter cool air ventilation fur determining rough rice cooling method in the storage and dry bin. The rough rice storage characteristics of two test conditions, winter cool-air ventilation storage and ambient temperature storage, were evaluated from January to July 2001, using a storage and dry bin of 300-ton capacity. Results of this research are as follows: Grain temperature was from $-5.1\~-8.5^{\circ}C$ after winter cool-air ventilation, and grain initial temperature for ambient temperature bin storage was $0.3\~1.9^{\circ}C$. Moisture content of rough rice decreased from $0.28\;to\;0.93\%$ and from $1.53\;to\;1.92\%$ to compare with original moisture contents for winter cool-air ventilation, and for ambient temperature bin storage, respectively. Broken ratio of brown rice from winter cool-air ventilation bin increased from $0.16\;to\; 0.92\%$, and brown rice broken ratio was from $2.24\;to\;2.86\%$ for ambient temperature bin storage to compare with initial broken ratio. Hardness of stored rice increased along storage period increase in alt storage methods, and cooling bin storage increased rice hardness of 0.271kgf: this increasing was lower then the other methods from 0.059 to 2.239kgf. Germination rates were decreased approximately 9.03, 3.14 and $3.20\%$ for upper, middle, and bottom of ventilating winter air bin, respectively, and germination rates of 2.70, 3.47 and $4.14\%$ were approximately decreased for upper, middle, and bottom parts of ambient temperature bin storage, respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.73-82
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• 2005

This study was performed to evaluate the need for heating wastewater to enhance treatment efficiency of organic matter (BOD, SS) during cold winter in newly developed Absorbent Biofilter System (ABS) which was established in the Suwon Campus of the Seoul National University. Treatments consisted of non-heating (2000 year) and heating(2001, 2002 year), and sampled data were analyzed during cold winter period as well as post winter period to investigate the influence of heating after winter season. Even the average air temperature showed only $0.4^{\circ}C$ difference between two experimental years, the difference in the average effluent temperature during cold winter period between heating and non-heating experiment was approximately $11^{\circ}C$. The average effluent concentration of organic matter in non-heating treatment exceeded the Korean standards for water quality of discharged effluent in riparian area (BOD and SS 10 mg/L); however, the standards were met in case of heating treatment during both winter and post winter period. Therefore, the need fur heating wastewater during cold winter season in ABS was justified. On the other hand, there was no improvement of treatment efficiency in T-N and T-p, but we observed the more activated nitrification as increasing the wastewater temperature. Because the average underground temperature was $5^{\circ}C$ higher than the average air temperature during cold winter period, we recommend that the ABS can be established in the underground rather than on-ground for saving the heating cost.

• Journal of the Korean association of regional geographers
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• v.12 no.4
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• pp.461-474
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• 2006

This paper aims to analyze regional characteristics of unusual temperature events on summer and winter. The major data used in this study are the daily mean temperature of summer (June-August) and winter (December-February) and wind field on 850 hPa height. Regions of unusual temperature are divided into five regions by the monthly frequency of unusual temperature occurrence. The divided regions are following as: the middle east coastal region (I) where the summer unusual high temperature occurrence frequency is highest; the Gyunggi west coastal and northern middle inland region (II) where winter unusual low temperature occurrence frequency is highest and winter unusual high temperature occurrence frequency is low; the western middle and south region (III) where unusual temperature occurrence ratio is not concentrated on specific season; the forest and southern east region (IV) where unusual high temperature is low; and the south coastal and Jeju island region (V) where winter unusual high temperature is highest.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.3
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• pp.95-102
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• 2000

The northward shift of the cultivation region of winter barley has been considered because of consecutive warm winters from the middle of 1980's. There was 1.02$^{\circ}C$ rise in mean air temperature during winter barley cropping season from 1975 to 1998. During this period, the maximum air temperature affected the mean air temperature rise rather than the minimum air temperature. The amount of mean precipitation was 513.3 mm during winter barley cropping season from 1975 to 1998 and was least in 1992. Sunshine hours has increased little by little in the all regions except rural regions. The air temperature during winter barley cropping season from 1987 to 1999 in which the winter was warm was higher than the normal air temperature(1961~1990). On the other hand, the air temperature during winter barley cropping season from 1974 through 1986 was similar to the normal air temperature. The amount of mean precipitation during winter barley cropping season from 1987 through 1999 was similar to the normal precipitation except April. During this period, the amount of mean precipitation of April was lower by 26 mm than the normal year(1961~1990). Sunshine hours during winter barley cropping season from 1987 to 1999 decreased generally in comparison with a normal year. Considering the air temperature rise during wintering from 1987 to 1998, it might be possible to extend the cropping area of winter barley northward.

• Journal of the Korean Geographical Society
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• v.41 no.1 s.112
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• pp.94-105
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• 2006

This paper aims to analyze changes of unusual temperature events on summer and winter and their controlling factors. There has been obviously an increased frequencies of summer unusual high temperature occurrence and decreased frequencies of winter unusual low temperature at most of stations. WMI, winter SHI and AOI might be essential for prediction of unusual temperature during winter and summer OHI and spring NPI for summer unusual low temperature. These factors are crucial because they reflect the recent global warming trend as well as have apparent associations with unusual temperature occurrence frequency in Korea.