• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제3권2호
• /
• pp.81-89
• /
• 1999

This study estimates the correlation dimensions of the land-sea breeze phenomenon, that has a clear diurnal cycle, in order to gain a more detailed understanding of this phenomenon. The data adopted include north-south wind velocity component(v) and temperature(T) time series that were observed at Kimhae Airport and Inje University over a period of 5 days, from the 4th to the 8th of August, 1994. The embedding phase space of the time series were reconstructed from 2 to 14 dimensions, and the correlation dimensions of the attractors were then estimated. The results show that the land-sea breeze phenomenon exhibits a deterministic chaos with non-integer correlation dimension values between 2 and 3. Accordingly, 3 is the minimum number of independent variables required to model the dynamics of the landsea breeze phenomenon in the Kimhae area. Since the saturated embedding dimension, when the correlation dimension remains unchanged, is larger for the wind velocity v-component than for temperature, this indicates that wind velocity is susceptible to topology.

• 한국정밀공학회지
• /
• 제13권2호
• /
• pp.159-167
• /
• 1996

The effect of atmospheric gas on the surface cleanliness in the batch annealing furnace(BAF) is presented. It is very important to improve the surface cleanliness to investigate the surface defects such as carbon contamination, smudge and yellow color phenomenon on the surface of steel sheet. In order to study the occurrence of surface defects of steel sheet, the annealing operations were carried out in the H2 BAF with 75% hydrogen and conventional BAF with 4% hydrogen. The hydrogen is important factor that affect the energy saving in the entire annealing cycle and the surface cleanliness. In the conventional BAF, it shows that to protect the yellow color phenomenon the proper finish temperature is $80^{\circ}C$ and in the smudge sample the oxidized thickness has the depth of $120{\AA}$.

• 한국환경과학회지
• /
• 제23권1호
• /
• pp.25-37
• /
• 2014

In the present study, we analyzed precipitation patterns and diurnal variation trends of hourly precipitation intensity due to climate change. To that end, we used the hourly precipitation data obtained from 26 weather stations around South Korea, especially Busan, from 1970 to 2009. The results showed that the hourly precipitation was concentrated on a specific time of day. In particular, the results showed the so-called "morning shift" phenomenon, which is an increase in the frequency and intensity of hourly precipitation during the morning. The morning shift phenomenon was even more pronounced when a higher level of hourly precipitation intensity occurred throughout the day. Furthermore, in many regions of Korea, including Busan, this morning shift phenomenon became more prevalent as climate change progressed.

• 한국대기환경학회지
• /
• 제10권1호
• /
• pp.1-23
• /
• 1994

Visibility impairment phenomenon due to various air pollutants is a highly complex problem To understand this problem in Seoul, (1) theoretical background of visibility impairment; (2) methods to quantify visual range and to assess contribution of each air pollutant to the visibility impairment problem; and (3) previous field measurements and modeling studies, both in Korea and abroad, are critically reviewed.

• 한국대기환경학회지
• /
• 제17권6호
• /
• pp.487-492
• /
• 2001

In this technical information, the springtime TSP measurement data between 1993 and 1996 at Kosan are presented. Based on the data, it was found that the concentrations of crustal species increase when Yellow Dust phenomenon occurs. Among anthropogenic species, the concentration of Pb and NO$_3$$^{[-10]}$ increase when Yellow Dust phenomenon occurs. Further research agenda are discussed to study the effects of Yellow Dust.

• 한국대기환경학회지
• /
• 제6권2호
• /
• pp.183-191
• /
• 1990

To check the possible transportation of gaseous air pollutants with the particles of yellow sand in the movement of air masses during the Yellow Sand Phenomenon, the concentrations of such air pollutants as TSP, $SO_2, CO, NO_x, O_3 and N-CH_4$, and wind wpeed were measured during the Yellow Sand Phenomenon (April 8 $\sim 10, 1990) and they were compared with those during the normal times in Korea. Meanwhile dust color of the samples during the Yellow Sand Phenomenon was the color of sand, that during the normal times was dark-brown. The concentrations of dusts; water soluble components, and metallic components of soil-originated elements during the Yellow Sand Phenomenon were higher than those during the normal times. While the metallic components in the dusts during the Yellow Sand Phenomenon were from soil-originated elements, those during the normal times were of both soiloriginated and sea-originated elements. The change of hourly concentrations of air pollutants showed bi-modal distribution during the two periods. Generally, the concentration levels of air pollutants during the Yellow Sand Period were higher than those during the normal times. Although similarity was observed in the primary sources, differences were observed in the dynamics of the secondary sources due to chemical reactions of the air pollutants during the two periods.

• 한국대기환경학회지
• /
• 제15권5호
• /
• pp.625-638
• /
• 1999

Air quality modeling for coastal urban region has been composed of a complex system including meteorological, chemical and physical processes and emission characteristics in complex terrain. In this study, we studied about an effect prediction for deposition phenomenon affecting on air quality in Pusan metopolitan metropolitan city. In air quality modeling including ship sources, a situation considered deposition process habe better result than not considered when compared with observed value. Air pollutants emitted into urban air during the daytime nearly removed through urban atmosphere polluted. Also these phenomena correlated concentration variation connent with sea/land breezes and terrain effect. Therefore we conclude that the concentration was low at daytime when deposition flux is high, and deposition effect on industrial complex and Dongrae region is considerable in particular.

• 한국대기환경학회지
• /
• 제16권5호
• /
• pp.487-497
• /
• 2000

Spring time is a favorable season to be easily observed the Yellow Sand phenomenon in East Asia. In particular most of the phenomenon tend to occur in April. However, Yellow Sand phenomenon was observed from almost the whole country of Korea in winter of 1966, 1977 and 1999. The features of the synoptic weather pattern in the source regions, air stream flow between the source region and Korea, the measurement of TSP concentration, aerosol size distribution, and chemical composition of snow samples associated with Yellow Sand phenomenon were investigated. The result showed the characteristic evolutionary feature of the synoptic system associated with Yellow Sand phenomena, that is, a strong low level wind mobilized the dust within 2 or 3 days before Yellow Sand phenomenon being observed in Seoul. The wind was remarkably intensified in the source region on January 24, 1999 under the strong pressure gradient, A trajectory analysis showed that the Yellow Sand particle could be reached to Korea within 2 days from the source region, Gobi desert, through Loess plateau and Loess deposition region. The TSP concentration at the top of Kwanak mountain during the Yellow Sand phenomenon is abruptly increasing than the monthly mean concentration. The size resolved number concentration of aerosols ranging from 0.3 to 25${\mu}{\textrm}{m}$ was analyzed during Yellow Sand episode. It was evident that aerosols were distinguished by particles in the range of 2-3 ${\mu}{\textrm}{m}$ to result in the abrupt increase in January 1999, After Yellow Sand phenomenon, there was heavy snow in Seoul. By the analysis of snow collected during that time, it was observed that both the Ca(sup)2+ concentration and pH were increased abnormally compared to those in the other winter season.

• 분석과학
• /
• 제36권4호
• /
• pp.191-197
• /
• 2023

Radioactivity concentrations for natural radionuclides were determined from fine dust samples collected in Jeju, Korea according to atmospheric events (Asian dust, haze, fog-mist, and non-event), and radium equivalent activity was calculated. The mean atmospheric radioactivity concentrations for ²³⁸U, ²³²Th, and ⁴⁰K in 127 fine dust samples were 0.49, 0.24, and 7.23 µBq m^-3, respectively, and the radium equivalent activity was 33.25 Bq kg^-1. The mean concentrations of ²³⁸U and ²³²Th in the fine dust during the Asian dust period were 1.31 and 1.60 µBq m^-3, respectively, above the global average, while the values for the other three atmospheric events were lower. The ratio of ²³²Th/²³⁸U radioactivity during the Asian dust period was 1.22, higher than the ratio for the other three atmospheric events.

• 한국대기환경학회지
• /
• 제8권1호
• /
• pp.52-57
• /
• 1992

The influence of soil particles on TSP transported from China contient to Seoul by the Yellow sand phenomenon was investigated from the analytical results of TSP during three years, April 1988 through May 1991. The TSP was collected by a high volume air sampler abour five times a month, and then analyzed by A.A.S. and UV-Visible spectrophotometry. During the Yellow sand phenomenon, the mean concentration of TSP at Seoul was about 578 $\mug/m^3$ and three times higher than that in the ordinary time which was about 194 $\mug/m^3$. The mean contribution of soil particles calculated by Al content to TSP was 28% in the ordinary time, but the degree of contribution jumped to about 60% during the Yellow sand phenomena. The concentration of soil particles transported from China continent to Seoul was estimated to be 175.1 $\mug/m^3$ on an average(104 $\mug/m^3-231 \mug/m^3$).