• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.339-345
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• 2018

Sunrise and sunset times differ depending on location and date. Previous studies conveniently but monotonously applied day and night times set up. This research defined the daytime and nighttime while considering the time of twilight according to the date and the location of ship collision accidents. Classifying the frequency of ship collision accidents with this standard, we conducted a chi-squared test for the difference between daytime and nighttime. The frequencies of ship collision accidents according to daytime and nighttime was compared by season, month, and time, and all of them showed statistically significant differences. The highest number of daytime ship collisions was 11.6 %, in June, and nighttime collisions peaked at 13.7 %, in December. The most frequent hour for daytime ship collisions was 0700h-0800h, at 10.2 %, and nighttime collisions peaked between 0400h-0500h, at 16.9 %. It is clear that the criteria used in previous studies cited was applied without any theoretical basis and likely only for the convenience of the researchers. It was found that results depend on what criteria are applied to the same research data. This study shows that statistical analyses of marine accidents, traffic volume, and congestion density should be carried out quantitatively while considering daytime and nighttime hours for each particular location and date.

• Journal of Environmental Science International
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• v.3 no.3
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• pp.217-228
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• 1994

The climatological study of temperature inversion was conducted at the Tsukuba of Japan during the cold half year, the periods of which were both from October 1981 through March 1982 and from October 1982 through March 1983. Meteorological phenomena were observed to appear both from l0m to 200m above the ground and from the surface to 300hPa. The data collected from those phenomena were analyzed in terms of statistics and investigated from a synoptic point of view. The results are as follow. The dispersion of the surface inversion happens right after sunrise through the whole period. The higher the upper layer is, the later that happens. Up to a height of 200m, the wind speed at a height of 25m has the greatest effect on temperature, but on the other hand the wind speed at a height of l0m has the greatest effect on inversion intensity.

• Journal of Environmental Science International
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• v.6 no.6
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• pp.613-628
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• 1997

Diurnal variations of air quality due to the characteristic features of local weather phenomena over Kunsan, Taegu, and Pohang are analyzed using various synoptic wand fields and the characteristics of local weather during the period of 1990 to 1992. The air pollutants analyzed are sulfur dioxide($SO2_$), nitrogen dioxide($NO_2$), and oxidants ($0_3$). The synoptic wind fields estimated at over the 850 hPa geopotential height are divided in terms of four wand directions and two wand speed categories for each season. The synoptic weather conditions are also classified Into two categories depending on the 850 hPa cloud amounts. The present study shows that the $SO_2$ concentration over Kunsan, and Taegu was maximum at the two or three hours after sunrise and second primary was three or flour hours after sunset. On the other hand, Its concentration over Kunsan was malnmum at 1900 LST or 2000 LST The $O_3$ concentration over the three cities shows Its mapdmum In the afternoon when the solar radiation is strong. The $NO_2$ concentration over Kansan shows in reverse proportion to the $O_3$ concentration over the Kunsan.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.757-772
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• 2003

We simulate the geographical effects on the onset time of sea breeze at Suyoung and Haeundae districts by using the LCM (Local Circulation Model). The following can be found out from the numerical simulation on Case I (real terrain) which considered the real geography of Busan metropolitan area. Especially, as a result of analyzing the land breeze path, it could be found along the coastline as it flows out through low land coastal area. To find out more about the effects of terrain and geography on the onset time of sea breeze, the results of numerical simulation of virtual geography are as follows. In Case II (flat terrain), to find out how the terrain slope affects the onset of sea breeze, flat land and the ocean was considered. As a result, convergence of nighttime air mass at a Suyoung area and nighttime strong wind speed phenomenon was not shown. In Case III (modified flat terrain), to find out the effects of the irregularity of coastline affecting the onset of sea breeze, numerical simulation was carried out by simplifying the complex coastline into segments of straight coastline. So land breeze system and changing process of sea breeze after sunrise at Suyoung and Haeundae was simulated almost in a similar manner. Through this we could find the effects of coastal irregularities on onset of sea breeze.

• The Korean Journal of Ecology
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• v.7 no.3
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• pp.99-108
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• 1983

Diurnal acid fluctuation, stomatal resistance, and solar radiation with regard to the cladode orientation were investigated in Opuntia lanceolata Haw. growing at WPeolryeong-ri, Hallim-eup, Chejudo, Korea. Diurnal changes of titratable acidity showed the typical CAM pattern in all investigated cladodes. Water tissue in the cladode had the same pattern of acid fluctuation as mesophyll tissue. Stomatal resistance was low during the night, increased rapidly to be a peak right after sunrise and decreased again thereafter. The southern side of the cladode showed higher stomatal resistance than the northern side during the day time. It suggests that the stomata of the northern side opens under diffuse radiation. The amount of solar radiation varied depending upon the cladode orientation. It is thought that C4 acids move inter and intra mesophyll tissues in the cladode through the unknown pathways. RuBP carboxyulase activity in the cladode was very high at 14:00, but was not significant at 01:00. PEP-carboxylase had high activities both at 14:00 and at 01:00. The results of this study showed the possibility that O. lanceolata Haw. had the C3, C4 and CAM photosynthetic patterns under the environmental conditions at Weolryeong-ri.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.11a
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• pp.121-124
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• 2006

This study was done with a goal to observe changes of color emotions according to time flow and light changes as well as to study its moaning of color experience of natural scene to modern city dwellers with artificial surroundings. Individuals develop various feelings after seeing a color, but there is sometimes a common feeling raised among these various feelings. This study aims to investigate the influence of natural colors of surroundings on the emotions of human beings. First of all, we tried to discover how feelings change after a person is reminded of a color through an experience (recognition) of a natural color. Second, differences in feelings resulting from color perception are analyzed after time passes (sunrise, daytime, and sunset) and the colors of natural surroundings change accordingly. Survey was done in the period of $Jul.8^{th}$ to $10^{th}$, 2005 with 100 people (55 male and 45 female) in various professions and various ages between twenties to forties as respondent.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.299-306
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• 2011

This paper examines relation between growth of adult top shell and their selectivity over different marine algae. For the study the top shell density and the algal species in different depth were surveyed by SCUBA. To test selectivity over different types of algae, five algal species including Ecklonia cava, Undaria pinnatifida, Ulva spp, Gelidium amansii and Sargassum spp were provided to top shells in indoor water tank condition. In the field survey, the wet weight of Ecklonia cava was significantly (r = 0.612, p < 0.05) correlated to the shell length (SL) of top shell. In the indoor water tank experiment conducted over 12 hours after sunrise, adult top shell (SL > SL 4.5 cm) tended to select Ecklonia cava and Undaria pinnatifida, which are common and abundant algal in the subtidal waters in Jeju Island. Our field survey and the indoor experiment suggest that E. cava and U. pinnatifida could be food preferred by adult top shell in its habitat.

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.71-76
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• 2018

The long-tailed goral (Naemorhedus caudatus) has slowly recolonized habitats in South Korea. Because it is necessary to know the status of groups in recolonized areas, we determined detection frequencies and group sizes using camera trapping, a non-invasive monitoring method. In Uljin, a far southern goral habitat in South Korea, we used a Moultrie 5.0 camera and mineral block as bait during the breeding season in BaekAm Mountain (148 days, 18 May to 11 October) and Geumjong Mountain (63 days, 18 May to 18 July) in 2010. Totally, 155 images were captured in BaekAm Mountain, whereas four images were captured in Geumjong Mountain. The species was most frequently detected at sunrise (05:00-08:00) and sunset (18:00-20:00). Through population structure evaluation, we identified at least 11 individuals, including one solitary mature male, four females, four kids, and two solitary subadults in BaekAm Mountain. However, in Geumjong Mountain, we identified only two individuals (female with kid). Monitoring efficiency in the recolonized area differed depending on population density and habitat conditions. Because we could evaluate the population structure, and behavioral patterns in the study sites, monitoring using camera traps could be applied for the recolonized habitats in South Korea.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.583-591
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• 2007

In this study, meteorological characteristics concerning the occurrence of fog are analyzed using 4-years (2000-2003) data at Chuncheon. From the analysis of meteorological characteristics, the fog at Chuncheon occurred before sunrise time and disappeared after that time and lasted for 2-4 hours. When fog occurred, on the whole, wind direction was blew the northerly and wind speed was below 2.1 m/s. Especially, about 42 % of foggy day fell on the calm($0{\sim}0.2m/s$) conditions. The difference between air temperature and dew point temperature near the surface were mainly less than $2^{\circ}C$. For the lack of water surface temperature, the water sur-face temperature was calculated by using Water Quality River Reservoir System (WQRRS). In Chuncheon, there is close correlation between the frequency of fog day and outflow from Soyang reservoir and high frequency of occurrence due to the difference between air and cold outlet water temperature.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1337-1344
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• 2013

We examined urban heat island intensity in Seongseo, Dae gu, South Korea, where a large area of water is located within the suburb. We found a maximum urban heat island intensity of $4.2^{\circ}C$, which occurred around 7 PM in the summer season. Throughout the remainder of the year, we observed the largest heat island intensity levels during late night hours. In contrast, the winter season displayed the smallest values for heat island intensity. Our results conflicted with heat island intensity values for cities where suburbs did not contain water areas. Generally, cities with suburbs lacking water displayed the largest heat island intensity levels before sunrise in the winter season. We also observed negative urban heat island intensity levels at midday in all seasons except for the summer, which is also in contrast with studies examining suburbs lacking water areas. The heat island intensity value observed in this study ($4.2^{\circ}C$) was relatively large and fell between the averages for, Asia and Europe according to the relationship between urban population and heat island intensity.