• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.65-72
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• 1992

It is believed that the lower cold water is formed by winter cooling in the north of the East(Japan) Sea. To examine its effect on the general circulation of the East Sea, we performed a two-layer numerical model with realistic bottom topography. First a circulation is generated by imposing only an inflow and an outflow which is then modified by adding the cooling effect in the north. The interface between the two layers rises due to cooling and propagates along the coast as internal Kelvin waves. About 7 months after the cooling starts, all coastal areas of the basin have higher elevation than that in offshore region. This induces baroclinic currents resulting in clockwise(anticlockwise) circulation in upper (lower) layer of the basin. It is concluded that the East Korean Warm Current strengthens as a result of lower cold water formation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.359-371
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• 1998

The cold water event near Gampo-Ulgi coast in summers between 1987 and 1994 are studied using sea surface temperature records at the coastal stations, ocean winds measured by SSM/I and AVHRR SST images. The response time of the cold water events by upwelling is less than two days and surface cold water expands up to the Ulleung Island. An analysis of 61 upwelling favorable winds indicates that the surface water temperature drops more than $1^{\circ}C\;in\;80\%$ of the south-westerly wind events. The linear correlation coefficient between wind impulses and the maximum temperature drops is good (0.6). It is found that the major cause of the cold water events is the along-shore wind in summer. The bottom topography and off-shore direction of the East Korean Warm Current by the potential vorticity conservation near Gampo coast also contribute the formation of the cold water along the southeast coast of Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.107-112
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• 2005

Road is built continuously along with development of industry and cut slope is happened necessarily in road construction. Geoengineers are executing cut slope stability analysis considering various cut slope condition such as topography, geology, hydraulic condition and so on. The Tertiary Jungja Basin is located in the southeastern coastal area of the Korea Peninsula. Jungja Basin area is created by geotectonic movement of the plate after Early Miocene epoch. The northwestern and southwestern boundary of the basin is fault zone. The Basement rock is hornfels (Ulsan Formation). Basin-fills consist of extrusive volcanic rock(Tangsa Andesites), unconsolidated fluviatile conglomerate(Kangdong Formation) and shallow brackish-water sandstone(Sinhyun Formation). The characteristics of cut slopes in this area is different with cut slopes in the other site. Soil layers in this area is unconsolidated sediments and is not formed the weathering and erosion of the rock. So, the depth of soil layer is very thick. Faults of this area are northwest-southeast and northeast-southwest direction. Expandible clay mineral as smectite, chlorite et al. detected from fault gouge using XRD. Therefore, Jungja Basin area must consider the characteristics of the faults and soil layers thickness necessarily cut slopes stability analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.457-473
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• 1992

The first order wave equation over a double shelf has wind stresses on both coastal boundaries and wind stress curl forcing across the shelf. In the Yellow Sea, the effect of wind stress curl can be neglected as a forcing of shelf waves. The decay distance of Kelvin waves is much greater than that of continental shelf waves so that Kelvin waves are transmitted nearly intact through the northern embayment. The numerical method of characteristics has been modified to accomodate wave propagation of opposite directions. Using a little more realistic coastline, the wave model hindcast has been improved for current velocity, but hardly for sea level. It means that Kelvin waves, which mainly determine sea levels, are affected little by the change of bottom slope. For a better hindcast of sea level, input energy of Kelvin waves transmitted from the East China Sea is needed. The basic structure of downwind flows along the coasts and upwind flows along the trough supports the seasonal circulations driven by monsoon winds in the Yellow Sea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.897-904
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• 2006

The eastern coast of northeastern Brazil (NEB), a coastal land-strip up to 300 km wide and stretching out from Rio Grande do Norte $(5^{\circ}S)$ State down to the south of Bahia State $(17^{\circ}S)$, experiences different rain producing systems, such as distrubances in the south-east trade winds, frontal systems penetration, land-sea breeze circulation and local convection associated with the topography and moisture flux convergence. The annual total rainfall ranges from 600 inland to 3000 mm on the coast. Rainfall totals 5 to 12 times the focal climatic means were recorded in various regions of Alagoas state in January 2004. It was estimated that 46,000 people were homeless, with material damages exceeding US$10 million as a consequence of the ensuing floods. GOES infrared images analysis showed that the main weather system responsible for this anomalously high rainfall totals was an Upper Troposphere Cyclonic Vortex (UTCV), which formed at about a $27^{\underline{\circ}}W\;e\;12^{\underline{\circ}}S$ and remained active for the entire month of January over NEB.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.29-40
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• 2011

In this study, the effects of an urban thermal environment on air quality were investigated using hourly surface weather observation data and air quality data over six summers from 2000 to 2005 in two cities on the Korean Peninsula. One, the city of Daegu, is representative of basin topography and the other, the city of Busan, represents a coastal area. It is known that the characteristics of an urban thermal environment are represented as an "urban heat island". Here, we focus on the nighttime urban thermal environment, which is called a "tropical night", during the summer. On tropical nights in Busan, the temperature and cloud cover levels were higher than on non-tropical nights. Wind speed did not appear to make a difference even on a tropical night. However, the frequency of southwestern winds from the sea was higher during tropical nights. The prevailing southwest winds in all areas meant an inflow of air from the sea. So at most of the air quality stations, the ozone concentration during tropical nights was lower than during non-tropical nights. In Daegu, the tropical nights had higher temperatures and cloud covers. Despite these higher temperatures, the ozone concentration during the tropical nights was lower than that on non-tropical nights at most of the air quality stations. This feature was caused by low irradiance, which in turn caused an increased cloud cover. Wind speed was stronger during the tropical nights and dispersed the air pollutants. These meteorological characteristics of the tropical nights reduced ozone concentrations in the Daegu Basin.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.3
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• pp.29-45
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• 2022

For biodiversity conservation, the importance of beta-diversity which is changes in the composition of species according to environmental changes has become emphasized. However, given the systematic investigation of species distribution and the accumulation of large amounts of data in the Republic of Korea(ROK), research on the spatialization of beta-diversity using them is insufficient. Accordingly, this research investigated the applicability of the Generalized Dissimilarity Modeling(GDM) to ROK, which can predict and map the similarity of compositional turnover (beta-diversity) based on environmental variables. A brief overview of the statistical description on using GDM was presented, and a model was fitted using the flora distribution data(410,621points) from the National Ecosystem Survey and various environmental spatial data including climate, soil, topography, and land cover. Procedures and appropriated spatial units required to improve the explanatory power of the model were presented. As a result, it was found that geographical distance, temperature annual range, summer temperature, winter precipitation, and soil factors affect the dissimilarity of the vegetation community composition. In addition, as a result of predicting the similarity of vegetation composition across the nation, and classifying them into 20 and 100 zones, the similarity was high mainly in the central inland area, and tends to decrease toward the mountainous areas, southern coastal regions, and island including Jeju island, which means the composition of the vegetation community is unique and beta diversity is high. In addition, it was identified that the number of common species between zones decreased as the geographic distance between zones increased. It classified the spatial distribution of plant community composition in a quantitative and objective way, but additional research and verification are needed for practical application. It is expected that research on community-level biodiversity modeling in the ROK will be conducted more actively based on this study.

• Industry Promotion Research
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• v.7 no.1
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• pp.75-80
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• 2022

Cui Bu (1454~1504 BC), named Yuanyuan, named Jinnan. Served as the deputy manager of the Korean King Chosun Hongwenguan (fifth grade official). In 1487, on the way to Jeju Island to perform official duties, because his father died, he went home from the funeral on the third day of the first lunar month in 1488, but was unfortunately on the way. Encountered a storm, and drifting at sea for nearly half a month, he landed at the "Linhai County Boundary of Taizhou Prefecture, Zhejiang Province, Datang Kingdom" (now Sanmen County). Later, Cui Bu went to Hangzhou by land near Taizhou, where he landed, then via Hangzhou, took a boat along the Beijing-Hangzhou Grand Canal to Beijing, and from Beijing by land through Shanhaiguan, and returned to his country via the Yalu River. Cui Bu stayed in China for four and a half months, 136 days, and traveled nearly 9,000 miles. After returning to China, he wrote the book "Piaohailu" in Chinese. This diary-style book has a total of more than 50,000 characters, covering politics, military, economics, culture, transportation, and local customs in the early years of Hongzhi in the Ming Dynasty. The situation is an important document for studying China's Ming Dynasty coastal defense, political system, justice, canals, cities, topography, and folklore.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.669-678
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• 2022

The Haeundae beach and coast suffered synthetical dramatic changes especially in the nearshore topography by the beach nourishment project (i.e., 2013-2015). A previous study showed the rip current characteristics were changed according to the topographical change in terms of their magnitudes and likelihoods through numerical simulations using the FUNWAVE model. The magnitude and likelihood of rip currents decreased because the surfzone width decreased just after the beach nourishment. In this study, however, numerical simulations of the Haeundae rip currents were performed by using the 2017- and 2020-surveyed topographies changed for several years after the beach nourishment. From the simulation results using the topographies surveyed before and after the beach nourishment, it was found that the magnitude and likelihood of rip currents increased due to its increasing surfzone width in 2017 and 2020 and they might be increasing larger than those before the beach nourishment.

• Journal of Radiation Protection and Research
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• v.48 no.1
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• pp.28-43
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• 2023

Background: High-fidelity meteorological data is a prerequisite for the realistic simulation of atmospheric dispersion of radioactive materials near nuclear power plants (NPPs). However, many meteorological models frequently overestimate near-surface wind speeds, failing to represent local meteorological conditions near NPPs. This study presents a new high-resolution (approximately 1 km) meteorological downscaling method for modeling short-range (< 100 km) atmospheric dispersion of accidental NPP plumes. Materials and Methods: Six considerations from literature reviews have been suggested for a new dynamic downscaling method. The dynamic downscaling method is developed based on the Weather Research and Forecasting (WRF) model version 3.6.1, applying high-resolution land-use and topography data. In addition, a new subgrid-scale topographic drag parameterization has been implemented for a realistic representation of the atmospheric surface-layer momentum transfer. Finally, a year-long simulation for the Kori and Wolsong NPPs, located in southeastern coastal areas, has been made for 2016 and evaluated against operational surface meteorological measurements and the NPPs' on-site weather stations. Results and Discussion: The new dynamic downscaling method can represent multiscale atmospheric motions from the synoptic to the boundary-layer scales and produce three-dimensional local meteorological fields near the NPPs with a 1.2 km grid resolution. Comparing the year-long simulation against the measurements showed a salient improvement in simulating near-surface wind fields by reducing the root mean square error of approximately 1 m/s. Furthermore, the improved wind field simulation led to a better agreement in the Eulerian estimate of the local atmospheric dispersion. The new subgrid-scale topographic drag parameterization was essential for improved performance, suggesting the importance of the subgrid-scale momentum interactions in the atmospheric surface layer. Conclusion: A new dynamic downscaling method has been developed to produce high-resolution local meteorological fields around the Kori and Wolsong NPPs, which can be used in short-range atmospheric dispersion modeling near the NPPs.