• Journal of the Korean earth science society
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• v.38 no.5
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• pp.345-356
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• 2017

It is important to understand the variability of tropospheric ozone since it is both a major pollutant affecting human health and a greenhouse gas influencing global climate. We analyze the characteristics of East Asia tropospheric ozone simulated in a chemistry-climate model. We use a global chemical transport model, driven by the prescribed meteorological fields from an air-sea coupled climate model simulation. Compared with observed data, the ozone simulation shows differences in distribution and concentration levels; in the vicinity of the Korean Peninsula, a large error occurred in summer. Our analysis reveals that this bias is mainly due to the difference in atmospheric circulation, as the anomalous southerly winds lead to the decrease in tropospheric ozone in this region. In addition, observational data have shown that the western North Pacific subtropical high (WNPSH) reduces tropospheric ozone across the southern China/Korean Peninsula/Japan region. In the model, the ozone changes associated with WNPSH are shifted westward relative to the observations. Our findings suggest that the variations in WNPSH should be considered in predicting tropospheric ozone concentrations.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.2
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• pp.209-217
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• 2005

The energy balance of the surface layer of the water (the Yellow Sea, the East China Sea and the East Sea) was examined using satellite data. Variations of the net heat flux were similar to those of the latent heat flux which was more intensive than the sensible heat flux. The sensible heat flux was affected the difference between the sea surface temperature and the air temperature and was less important over the Yellow Sea. The maximum of the latent heat flux occurred in autumn when the air is drier and the wind is stronger. The shortwave radiation flux decreased with the latitude and depended on the cloudiness as the longwave radiation flux does. Annual variations of heat fluxes show that the latent heat flux was more intensive over the East China Sea than the East Sea and the Yellow Sea, while the spatial differences of the other heat fluxes were weak.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.1-13
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• 2020

Recently, a heavy rainfall with high spatial variation occurred frequently in the Korean Peninsula. The meteorological event that occurred in Busan on 3 May 2016 is characterized by heavy rain in a limited area. In order to clarify the reason of large spatial variation associated with mountain height and location of low level jet, several numerical experiments were carried out using the dynamic meteorological Weather Research and Forecasting (WRF) model. In this case study, the raised topography of Mount Geumjeong increased a barrier effect and air uplifting due to topographic forcing on the windward side. As a result, wind speed reduced and precipitation increased. In contrast, on the downwind side, the wind speed was slightly faster and since the total amount of water vapor is limited, the precipitation on the downwind side reduced. Numerical experiments on shifting the location of the lower jet demonstrated that if the lower jet is close to the mountain, its core becomes higher due to the effect of friction. Additionally, the water vapor convergence around the mountain increased and eventually the precipitation also increased in the area near the mountain. Hence, the location information of the lower jet is an important factor for accurately predicting precipitation.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1513-1523
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• 2015

In order to clarify the characteristics of PM10 in coastal and inland cities and their variation statistical analysis were carried out using environmental and meteorological data observed at Busan and Daegu metropolitans during 4 year from 2010. Averaged PM10 concentration was higher in industrial area than any other land-use sites, and its maximum value reach on over $50{\mu}g/m^3$ at Jangrim site in Busan. Temporal and spatial variations of PM10 concentration in Busan were more sharply, since topograph and mesoscale wind pattern in Busan is more complicated than those in Daegu. Correlation of PM10 concentrations between sites within Daegu appeared strongly and maximum values $R^2$ is about 0.8. This indicate that because wind pattern induced by mesoscale forcing in Daegu are well unified, the variation of PM10 concentration tends to be similar in all sites within Daegu. However, due to complicate wind pattern induced by topography and coastal line, PM10 correlation of sites within Busan was weaker in comparison with in Daegu. And correlation of PM10 at same lane-use in Busan and Daegu tend to be related to the intensity of meteorological forcing, which can decide the intensity of wind pattern.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.423-433
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• 2014

This study examined the short-term variability of $CO_2$ concentrations measured at the Gosan site ($33^{\circ}17^{\prime}N$, $126^{\circ}10^{\prime}E$) in Jeju, Korea for the last 9 years from 2002 to 2010. The weekly distribution shows higher $CO_2$ concentrations during weekends than weekdays which implies the impact of local emissions because Jeju Island is one of the top tourist attraction in Korea. In diurnal variation, $CO_2$ concentration reached the maximum at 6 am and the minimum at 1 pm. The high $CO_2$ concentrations were mostly associated with lower wind speed (below 4 m/s) and easterlies, which was typical of summer night. In other seasons, however, the high concentrations were encountered under strong westerlies (8~16 m/s), which implies the influence of Chinese outflows. $CO_2$ concentrations were found to be highly correlated with meteorological parameters including wind speed, temperature, humidity, and solar radiation except for winter.

• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.405-418
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• 2014

Ontake Volcano, Japan, began to erupt without any precursors on September 27, 2014, at 11:52 AM, and it caused many losses of life. Although Japan's preparation manual and prevention for volcanic eruptions and volcanic hazards has been well established, it could not prevent damage due to the sudden eruption of the volcano. Soon after the eruption, however, Japan Meteorological Agency (JMA) led many organizations and institutions, including JMA's Volcanic Eruption Prediction Liaison Council, Meteorological Research Institute (MRI) and National Agriculture and Food Research Organization and they understood the eruption situation quickly and shared the information based on their close cooperation and contact systems. Through these efforts, JMA published the unified result to the public, informing the public of the situation around the volcano and about the eruption and of how the residents and climbers around the volcano should react to the volcanic hazards caused by the eruption. The Korean Government can learn how to respond to a future eruption of a volcano, such as Mt. Baekdu which has the potential to erupt in the foreseeable future.

• The Journal of the Petrological Society of Korea
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• v.20 no.3
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• pp.151-159
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• 2011

The geology of the Gonaengisool-oreum, Bonggae-dong, Jeju consists of Yeongpyeong-dong basalt, Shinan-dong basalt, Bonggae-dong basalt and cinder in ascending order. Yeongpyeong-dong and Shinan-dong basalt is situated at the mid-mountain slope in southern part of the Gonaengisool-oreum, and Bonggae-dong basalt is located at the Gonaengisool-oreum area and nortgbern low foot of the mountain. Bonggae-dong basalt is aa lava flows with thick clinker. The Gonaengisool-oreum is isolated small volcano, that is, a lava shield having wide crater in the summit with several small pit craters. The average basal elevation of the Gonaengisool-oreum cone is 297.5 m(highest 300 m and lowest 295 m), and the highest summit is 304.5 m, average cone basal width is 597.5 m and cone height is 7.9 m, and mean slope of $1.5^{\circ}$ for the flank of the shield cone.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.315-324
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• 2016

The relevant ministries, including the Ministry of Environment in Korea, provided Post-2020 Long-term Mitigation Target and Implementation Plan. The plan consisted of four Business As Usual (BAU) reduction levels by 14.7%, 19.2%, 25.7%, and 31.3% until 2030. The Korean government finalized the mitigation target of 37%. But all the initial alternatives were below the goal, 30% from BAU, that has been promised to the international community as well as set out in the Framework Act on Low Carbon Green Growth. In order to achieve a specific goal, performance management should pursue "Justify doing the right things." Otherwise, performance management would not work properly. According to Kingdon's Policy Stream Framework, abnormal alternatives are difficult to be presented as scenarios because alternative building should focus on the role of the need to adhere to the basic principles and professionals. Such a result is possible only when the policy actors does not balance themselves. Performance management statistics has been analyzed by 6 years CCPI data since 2011, taking into account the impact after enactment. This study also has been complemented by a variety of sources, including the media, documents, and artifacts during the period. As a result, raising awareness about climate change was analyzed as one of the solutions because the climate change issue affects the normal performance management throughout the life of the people to stay linked to the environment.

• Journal of the Korean earth science society
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• v.44 no.2
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• pp.105-118
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• 2023

In this study, we predicted the presence of fog with a one-hour delay using the XGBoost DART machine learning algorithm for Andong, which had the highest occurrence of fog among inland stations from 2016 to 2020. We used six datasets: meteorological data, agricultural observation data, additional derived data, and their expanded data. The weather phenomenon numbers obtained through naked-eye observations and the visibility distances measured by visibility meters were classified as fog [1] or no-fog [0]. We set up twelve machine learning modeling experiments and used data from 2021 for model validation. We mainly evaluated model performance using recall and AUC-ROC, considering the harmful effects of fog on society and local communities. The combination of oversampled meteorological data features and the target induced by weather phenomenon numbers showed the best performance. This result highlights the importance of naked-eye observations in predicting fog using machine learning algorithms.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.60-67
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• 2024

The majority of civil aviation accidents are caused by human factors, and especially for rotary-wing aircraft, accidents often occur in situations where pilots unexpectedly or unintentionally enter into instrument meteorological conditions (IIMC). This research analyzed the error rates of rotary-wing aircraft pilots under low visibility conditions from various angles to gain insights into flight characteristics and to explore measures to reduce accidents in IIMC situations. The occurrence rate of errors by pilots under low visibility conditions was examined using a flight simulator equipped with motion, with 65 pilots participating in the experiment. Flight data obtained through the experiment were used to aggregate and analyze the number of errors under various conditions, such as reductions in flight visibility, the presence or absence of spatial disorientation, and the pilot's qualifications. The analysis revealed peculiarities in flight characteristics under various conditions, and significant differences were found in the rate of error occurrence according to the pilot's qualification level, possession of instrument flight rules (IFR) qualifications, and during different phases of flight. The results of this research are expected to contribute significantly to the prevention of aircraft accidents in IIMC situations by improving pilot education and training programs.