• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.368-387
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• 2007

In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.120-132
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• 2008

Remotely sensed images from a satellite can be applied for detecting and quantifying spatial and temporal variations in terms of landuse & landcover, crop growth, and disaster for agricultural applications. The purposes of this study were to analyze topography using DEM(digital elevation model) and classify landuse & landcover into 10 classes-paddy field, dry field, forest, bare land, grass & bush, water body, reclaimed land, salt farm, residence & building, and others-using Landsat TM images in North Korea. Elevation was greater than 1,000 meters in the eastern part of North Korea around Ranggang-do where Kaemagowon was located. Pyeongnam and Hwangnam in the western part of North Korea were low in elevation. Topography of North Korea showed typical 'east-high and west-low' landform characteristics. Landcover classification of North Korea using spectral reflectance of multi-temporal Landsat TM images was performed and the statistics of each landcover by administrative district, slope, and agroclimatic zone were calculated in terms of area. Forest areas accounted for 69.6 percent of the whole area while the areas of dry fields and paddy fields were 15.7 percent and 4.2 percent, respectively. Bare land and water body occupied 6.6 percent and 1.6 percent, respectively. Residence & building reached less than 1 percent of the country. Paddy field areas concentrated in the A slope ranged from 0 to 2 percent(greater than 80 percent). The dry field areas were shown in the A slope the most, followed by D, E, C, B, and F slopes. According to the statistics by agroclimatic zone, paddy and dry fields were mainly distributed in the North plain region(N-6) and North western coastal region(N-7). Forest areas were evenly distributed all over the agroclimatic regions. Periodic landcover analysis of North Korea based on remote sensing technique using satellite imagery can produce spatial and temporal statistics information for future landuse management and planning of North Korea.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.63-76
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• 2011

This study purposes to develop a model to analyze soil loss in estimating prior disaster influence. The model of analyzing soil loss develops the soil loss analysis system on the basis of Internet by introducing cloud computing system, and also develops a standalone type in connection with HyGIS. The soil loss analysis system is developed to draw a distribution chart without requiring a S/W license as well as without preparing basic data such as DEM, soil map and land cover map. Besides, it can help users to draw a soil loss distribution chart by applying various factors like direct rain factors. The tools of Soil Loss Anaysis Model in connection with HyGiS are developed as add-on type of GMMap2009 in GEOMania, and also are developed to draw Soil Loss Hazard Map suggested by OECD. As a result of using both models, they are developed very conveniently to analyze soil loss. Hereafter, these models will be able to be improved continuously through researches to analyze sediment a watershed outlet and to calculate R value using data of many rain stations.

• Journal of Wetlands Research
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• v.13 no.1
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• pp.45-52
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• 2011

Seawater circulations between a bay and the open sea play an important role to make the ecosystem healthy, providing nutrient and oxygen to the benthic environments and cleaning up pollutions. The health of the benthic environment in a bay is closely related to the flushing characteristics of seawater. In this study, to estimate the seawater distribution and circulation characteristics of benthic environment in the Geunso bay, we calculated the hydraulic turn-over time by a hydro-hypsographic analysis. Digital elevation model (DEM) which was generated using waterline method based upon remotely sensed data and water depth of the subtidal zone estimated by echo-sounding survey was applied to the hydro-hypsograhic analysis through a geographic information system (GIS) spatial analysis. The results showed that 95% of the total area of the bay was tidal flat and the hydraulic turn-over time was 1.03 tidal cycle, which indicated that the flushing characteristics of the Geunso bay was very good. Geunso bay was revealed to occupy relatively wide area of benthic environment and to have relatively big tidal range over other domestic and foreign coastal environment, therefore it could have a better seawater circulation characteristics. This result can be effectively applied as fundamental information to establish the system for a quantitative estimate of health of coastal environment in the west coast of Korea and manage the ecosystem in benthic environments.

• Journal of the Korean earth science society
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• v.41 no.2
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• pp.95-110
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• 2020

Comparisons between two different surface temperatures from high-resolution ECMWF ReAnalysis 5 (ERA5) and Automated Synoptic Observing System (ASOS) observations were performed to investigate the reliability of the new reanalysis data over South Korea. As ERA5 has been recently produced and provided to the public, it will be highly used in various research fields. The analysis period in this study is limited to 1999-2018 because regularly recorded hourly data have been provided for 61 ASOS stations since 1999. Topographic characteristics of the 61 ASOS locations are classified as inland, coastal, and mountain based on Digital Elevation Model (DEM) data. The spatial distributions of whole period time-averaged temperatures for ASOS and ERA5 were similar without significant differences in their values. Scatter plots between ASOS and ERA5 for three different periods of yearlong, summer, and winter confirmed the characteristics of seasonal variability, also shown in the time-series of monthly error probability density functions (PDFs). Statistical indices NMB, RMSE, R, and IOA were adopted to quantify the temperature differences, which showed no significant differences in all indices, as R and IOA were all close to 0.99. In particular, the daily mean temperature differences based on 1-hour-averaged temperature had a smaller error than the classical daily mean temperature differences, showing a higher correlation between the two data. To check if the complex topography inside one ERA5 grid cell is related to the temperature differences, the kurtosis and skewness values of 90-m DEM PDFs in a ERA5 grid cell were compared to the one-year period amplitude among those of the power spectrum in the time-series of monthly temperature error PDFs at each station, showing positive correlations. The results account for the topographic effect as one of the largest possible drivers of the difference between ASOS and ERA5.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.168-187
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• 2006

Windy meteorological conditions and dried fire fuels due to higher atmospheric instability and dryness in the lower troposphere can exacerbate fire controls and result in more losses of forest resources and residential properties due to enhanced large wildland fires. Long-term (1979-2005) climatology of the Haines Index reconstructed in this study reveals that spatial patterns and intra-annual variability of the atmospheric instability and dryness in the lower troposphere affect the frequency of wildland fire incidences over the Korean Peninsula. Exponential regression models verify that daily high Haines Index and its monthly frequency has statistically significant correlations with the frequency of the wildland fire occurrences during the fire season (December-April) in South Korea. According to the climatic maps of the Haines Index created by the Geographic Information System (GIS) using the Digital Elevation Model (DEM), the lowlands below 500m from the mean sea level in the northwestern regions of the Korean Peninsula demonstrates the high frequency of the Haines Index equal to or greater than five in April and May. The annual frequency of the high Haines Index represents an increasing trend across the Korean Peninsula since the mid-1990s, particularly in Gyeongsangbuk-do and along the eastern coastal areas. The composite of synoptic weather maps at 500hPa for extreme events, in which the high Haines Index lasted for several days consecutively, illustrates that the cold low pressure system developed around the Sea of Okhotsk in the extreme event period enhances the pressure gradient and westerly wind speed over the Korean Peninsula. These results demonstrate the need for further consideration of the spatial-temporal characteristics of vertical atmospheric components, such as atmospheric instability and dryness, in the current Korean fire prediction system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.267-274
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• 2011

In this study, around Jeju area where climatic change is most considerably appearing in Han Peninsula, we prepared sea level rise height caused by sea level rise (Seogwipo 5.6 mm/yr, Jeju 5.3 mm/yr) and a sea level rise scenario for the case when an enlarged typhoon attacks during high water ordinary spring tide, and evaluated flooding area and effect on road and facility using Digital Elevation Model(DEM) and GIS Spatial Analysis Technique. As a result, the flooding areas were shown to be 2.9 $km^2$ in 2040, 5.4 $km^2$ in 2070, and maximum 5.4 $km^2$ in 2100. Analyzing the effect of flooding on each type of road, the local roads(Gun-do) were shown to be mostly affected. The most flood effected facilities were individual houses. Especially, as there is a possibility for casualties to occur due to disaster in Hwabuk-dong because the effect of flooding on individual houses in this area was shown to be high. In addition, flood on port facilities will considerably affect logistic and marine activities. This study is thought to be a basic data which can be utilized for establishment of strategic coping measures and policies of government affiliated organizations through analysis of effect of sea level rise on construction field.

• Journal of Korea Port Economic Association
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• v.38 no.3
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• pp.29-51
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• 2022

The International Maritime Organization (IMO) designated the Emission Control Area (ECA) in Northern Europe to reduce the NOx and SOx emissions from ships in the coastal areas. This study used Network slack-based measure (SBM) Data Envelopment Model (DEM) and Bootstrop Truncated Regression (BTR) model to analyze the ECA's impact on ferry companies' financial performances based on the financial data from eight ferry carriers in Northern Europe, the Mediterranean and North America from 2004 to 2017. To alleviate the problem of arbitrary variable selection in DEA, the variable selection criteria proposed by Dyson et al. (2001) were applied; the size of the company was considered through the Network SBM DEA model; and the company's profit-generating process was divided into stages to measure financial performance in more detail. In addition, the BTR model was applied to derive results that minimize the bias of the data. The study found that ECA regulations did not always negatively affect the shipping companies' financial performance. Rather, a steady increase in efficiency was observed for Northern European ferry companies which were subject to the strongest regulations. For North American ferry companies, government subsidies were found to have a significant impact on efficiency, and relatively small impact on efficiency due to the ECA and oil prices. For the Mediterranean ferry companies, efficiency values have decreased since the implementation of ECA regulation despite the lowest level of regulation in the region.