• Journal of Astronomy and Space Sciences
• /
• v.27 no.3
• /
• pp.231-238
• /
• 2010

We analyzed global positioning system (GPS)-derived precipitable water vapor (PWV) trends of the Korea Astronomy and Space Science Institute 5 stations (Seoul, Daejeon, Mokpo, Milyang, Sokcho) where Korea Meteorological Administration meteorological data can be obtained at the same place. In the least squares analysis, the GPS PWV time series showed consistent positive trends (0.11 mm/year) over South Korea from 2000 to 2009. The annual increase of GPS PWV was comparable with the 0.17 mm/year and 0.02 mm/year from the National Center for Atmospheric Research Earth Observing Laboratory and Atmospheric InfraRed Sounder, respectively. For seasonal analysis, the increasing tendency was found by 0.05 mm/year, 0.16 mm/year, 0.04 mm/year in spring (March-May), summer (June-August) and winter (December-February), respectively. However, a negative trend (-0.14 mm/year) was seen in autumn (September-November). We examined the relationship between GPS PWV and temperature which is the one of the climatic elements. Two elements trends increased during the same period and the correlation coefficient was about 0.8. Also, we found the temperature rise has increased more GPS PWV and observed a stronger positive trend in summer than in winter. This is characterized by hot humid summer and cold dry winter of Korea climate and depending on the amount of water vapor the air contains at a certain temperature. In addition, it is assumed that GPS PWV positive trend is caused by increasing amount of saturated water vapor due to temperature rise in the Korean Peninsula. In the future, we plan to verify GPS PWV effectiveness as a tool to monitor changes in precipitable water through cause analysis of seasonal trends and indepth/long-term comparative analysis between GPS PWV and other climatic elements.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.5 no.4
• /
• pp.278-284
• /
• 1993

A simplified TAC method was developed for the selection of design temperature and absolute humidity for peak cooling and heating load calculation with ETD method. And the design data of the 11 major cities in Korea were obtained. Based on the simplified TAC method, the design data for summer and autumn cooling season were selected by the TAC 5.0% of July through August and TAC 5.0% of October, respectively. But the design data for winter heating season were selected by the conventional TAC 2.5% of the full winter season.

• Proceedings of the KGS Conference
• /
• 2005.05a
• /
• pp.74-75
• /
• 2005

• Asian Journal of Atmospheric Environment
• /
• v.12 no.3
• /
• pp.244-254
• /
• 2018

Ulaanbaatar, the capital of Mongolia, is subject to high levels of atmospheric pollution during winter, which severely threatens the health of the population. By analyzing surface meteorological data, ground-based LIDAR data, and radiosonde data collected from 2008 to 2016, we studied seasonal variations in particulate matter (PM) concentration, visibility, relative humidity, temperature inversion layer thickness, and temperature inversion intensity. PM concentrations started to exceed the 24-h average standard ($50{\mu}g/m^3$) in mid-October and peaked from December to January. Visibility showed a significant negative correlation with PM concentration. Relative humidity was within the range of 60-80% when there were high PM concentrations. Both temperature inversion layer thickness and intensity reached maxima in January and showed similar seasonal variations with respect to PM concentration. The monthly average temperature inversion intensity showed a strong positive correlation with the monthly average $PM_{2.5}$ concentration. Furthermore, the temperature inversion layer thickness exceeded 500 m in midwinter and overlaid the weak mixed layer during daytime. Radiative cooling enhanced by the basin-like terrain led to a stable urban atmosphere, which strengthened particulate air pollution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.10
• /
• pp.387-393
• /
• 2016

A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

• Atmosphere
• /
• v.27 no.1
• /
• pp.79-91
• /
• 2017

It is imperative to understand the characteristics of atmospheric circulation patterns under the climate system due to its impact on climatic factors. Thus this study focused on analyzing the impact of the atmospheric circulation on the relationship between precipitation and temperature regionally. Here we used monthly gridded observational data (i.e., CRU-TS3.2, NOAA-20CR V2c) and HadGEM2-AO climate model by RCP8.5, for the period of 1960~1999 and 2060~2099. The experiment results indicated that the negative relationship was presented over East Asia and Europe during summer. On the other hand, at around Korea (i.e. EA1: $31^{\circ}N{\sim}38^{\circ}N$, $126^{\circ}E{\sim}140^{\circ}E$) and Northwestern Europe (i.e. EU1: $48^{\circ}N{\sim}55^{\circ}N$, $0^{\circ}E{\sim}16^{\circ}E$) in winter, strong positive relationship dominate due to warm moist advection come from ocean related to intensity variation of the East Asian winter monsoon (EAWM) and North Atlantic Oscillation (NAO), respectively. It was found that values of positive relation in EA1 and EU1 at the end of the 21st century is regionally greater than at the end of 20th century during winter since magnitude of variation of the EAWM and NAO is projected to be greater in the future as result of simulation with RCP 8.5. Future summer, the negative correlations are weakened in EA1 region while strengthened in EU1 region. For better understanding of correlations with respect to RCP scenarios, a further study is required.

• Journal of Mushroom
• /
• v.8 no.2
• /
• pp.51-58
• /
• 2010

Total eight different winter mushroom (Flammulina velutipes) strains were characterized by comparisons of fruiting body morphology, hardness and color after growing at different temperature. Although variations depending on the strains were observed, in general, both stipe length and pilus diameter were shorter while pilus thickness was bigger as growing temperatures were decreased. No significant differences in stipe thickness were observed. The ASI4065 and 4151 had the tallest stipe and the ASI4021 had the shortest stipe. The ASI4103 strain had the biggest pilus diameter. The ASI4153 had most thick pilus, while the ASI 4021 had least thick pilus. Also, the ASI4166 had the most thick stipe and the ASI4065 had the most thin stipe. The hardness of white mushrooms were increased by decreasing growth temperatures, while no relationships between the hardness of brown mushrooms. In most strains, stipe were much stronger than pilei and white mushrooms were harder than brown ones. The strain having most strong stipe was ASI4021. Both ASI 4021 and ASI4166 had the most strong pilus. The color of pilus has much lighter than that of stipe. White mushrooms had high brightness value ranging from 70-90, while brown mushrooms showed low brightness value from 30-70. Saturation value was higher in brown mushrooms. Based on our study, it was shown that environmental conditions had some effects on winter mushrooms, but genetic differences among strains were more important factors to determine most characteristics of winter mushrooms.

• Journal of the Korean housing association
• /
• v.19 no.4
• /
• pp.97-105
• /
• 2008

The purposes of this study were to determine the actual state of the indoor thermal environment in apartment units and to analyze the relationship between the living factors and indoor thermal elements. The field surveys consisted of measurements of physical elements and observations of living factors. In addition, the residents of 20 apartment units were interviewed to survey their subjective response. Field surveys were carried out from January to March 2007. Measuring elements were air temperature, globe temperature, and relative humidity. The results showed that the average of indoor temperature for the houses was $21.2{\sim}27.2^{\circ}C$, while 4 houses exceeded the comfort zone. The average of globe temperature for the houses was $21.3{\sim}27.5^{\circ}C$, while 6 houses exceeded the comfort zone. The mean relative humidity was $19.5{\sim}58.8%$, which is a relatively dry condition. The residents' average clothing value was $0.39{\sim}0.89$ clo(average 0.68 clo). The average thermal sensation vote on each room was $4.2{\sim}4.8$, which is 'neutral' to 'slightly warm'. Living factors had significant effect on indoor temperature in regression analysis were ventilation time(outdoor air exchange), opening time of door through balcony, and gas cooker use time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.5
• /
• pp.312-317
• /
• 2017

In this paper, the effects of environmental variables on the output of the floating photovoltaic water systems, which were installed at the Hapcheon dam in South Korea, were investigated, and the correlations between them were analyzed. The system output was linearly proportional to the solar radiation or irradiance. The output was large in spring and autumn because of high irradiance, but low in the summer when the solar module temperature was high. The influence of the module temperature on the system output was limited in the summer, during which the module temperature change affected the system output more than the change of the irradiance did. In addition, in winter and summer, the module temperature tended to decrease with increasing windspeed, but windspeed did not affect module temperature significantly in the spring and autumn. On the other hand, in winter and spring, the irradiance decreased as the windspeed increased because of movement (or circulation) of the photovoltaic modules.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.6
• /
• pp.813-818
• /
• 2013

In order to understand the co-culture impact of the sea squirt Halocynthia roretzi on the Pacific oyster Crassostrea gigas, we examined the filtration rate of the sea squirt in relation of water temperature ($5-25^{\circ}C$) and body weight. The filtration rate increased in relation to body weight and water temperature, indicating a clear positive correlation with the two variables. Due to the clear positive correlation between filtration rates at each temperature groups for acceptable collinearity, each constants at regression equation was further analyzed for a unified model of filtration rate. Therefore the filtration rate of H. roretzi was estimated as: Fr (L/h/animal)=$(0.1956+0.0182T){\times}DW^{0.7978EXP(-0.0273T)}$ for water temperature in the range of $5-25^{\circ}C$. The estimated filtration rates of H. roretzi were higher than those of C. gigas in the winter season (water temperatures below $16^{\circ}C$) in condition of equal body weight. Our results indicate that H. roretzi may have an advantage over C. gigas in food competition during the winter season when the two species are co-cultured.