• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.59-71
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• 2019

In Mountainous Districts Management Act of Korea Forest Service, slope and elevation criteria are operated to regulate the indiscriminate use of risky land parcels when forestland is converted to other land use types. However, there is a limitation in considering topographical variation with only such two indices in the land parcel. Therefore, in order to supplement insufficient criteria, the slope type standard was developed using Catena, and the ecological condition improved terrain standards. Firstly, the ratio of 'risky slope' in a target forestland parcel was defined to decrease the risk of disasters such as landslides. Secondly, the standard of the ecological location condition was proposed as ecological score by integrating age, diameter and soil depth classes in the target forestland parcels. Thereby, we could prepare reasonable standards that can reduce forestland disasters and ecological damages, as suggesting new topographical and ecological assessment methods for forestland use conversion.

• Journal of the Korean Geographical Society
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• v.48 no.1
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• pp.1-18
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• 2013

The mountain region in Korea has been known as 70% of total area and most Korean people have recognized Korea as the mountainous country. Those concepts are thought to be mislead by the definition of the Korea Forest Service for the mountain region. According to KFS's definition based on the land-use, the forest and farmland at the low altitude are also included in the mountain region. In this study, firstly, the geomorphological mountain region is extracted according to the definition of Kapos et al. (2000). The rates of mountain region in S. Korea, N. Korea, Korea Peninsular are 31%, 51%, 42% respectively. And the rates between mountain area and non-mountain area in the 300-1000m and 1000-2500m intervals are considerably different due to the existence of plateaus such as high-level plain surfaces. Secondly, using the overlay analysis in GIS, the distribution of mountain areas are compared with that of order-mountains' areas defined by Qui and SON (2010). Even in case of the 5th order, the highest order mountains, the hill & plain and non-mountain areas are included in that mountain area. It is possible to suggest that the definition of the KFS is completely different from the academic, realistic and epistemic definition for mountain area, and the geomorphological definition of mountain area is useful to classify the mountain area according to the its physical properties. Therefore, it would be expected that the definition contributes the development of methodologies on the scientific management of mountain area in future.

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.512-527
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• 2001

Separated flows passed complex geometries are modeled by discrete vortex techniques. The flows are assumed to be rotational and inviscid, and a new techlnique is described to determine the stream functions for linear shear profiles. The geometries considered are the snow cornice and the backward-facing step, whose edges allow for the separation of the flow and reattachment downstream of the recirculation regions. A point vortex has been added to the flows in order to constrain the separation points to be located at the edges, while the conformal mappings have been modified in order to smooth the sharp edges and to let the separation points free to oscillate around the points of maximum curvature. Unsteadiness is imposed to the flow by perturbing the vortex location, either by displacing the vortex from the equilibrium, or by imposing a random perturbation with zero mean to the vortex in equilibrium. The trajectories of passive scalars continuously released upwind of the separation point and trapped by the recirculating bubble are numerically integrated, and concentration time series are calculated at fixed locations downwind of the reattachment points. This model proves to be capable of reproducing the trapping and intermittent release of scalars, in agreement with the simulation of the flow passed a snow cornice performed by a discrete multi-vortex model, as well as with direct numerical simulations of the flow passed a backward-facing step. The results of simulation indicate that for flows undergoing separation and reattachment the unsteadiness of the recirculating bubble is the main mechanism responsible for the intense large-scale concentration fluctuations downstream.

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.188-200
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• 2000

On the basis of the Landsat TM scenes with 15 year's time differences, the topographic maps with 50 years differences, and the air photos with 25 years differences, we carried out the field survey for geology and forestry and analyzed the topographical change and the variation of the forest resource in Anmyundo. In terms of the discrimination of forest trees in Anmyumdo, the NDVI with larger than 0.5 in the winter season is the indicator of the surface of the pine tree land-cover. The peak values of NDVI appear on the surface of the pine aging 30 through 50 years and decrease a little and grossly stabilized over the more aging trees. The distinction of the deciduous forest and grass land from the pine tree was capable with the correlation with the abrupt seasonal variation of NDVI and the surface aspect. The great change of topography is detected in the region Changgiri due to the continuous tidal erosion since the canal construction about 370 years ago and along the all around coast of Anmyundo due to the reclamation for the paddy field. The surface area of the pine tree land-cover in Anmyundo was estimated 35.91 km$^2$ in 1986 and 33.15 km$^2$ in 1993, which is originated from the grassland development in the southeastern part of Anmyundo where the pine tree dominated by 1986. In the northen part of Anmyundo the surface area of the pine land-cover increased a little in 1993 comparing to 1986.

• Journal of Korean Society of Forest Science
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• v.81 no.1
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• pp.40-52
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• 1992

The use of meteorological information is essential in the industrial society. More specialized weather services are required to perform better industrial activities including forestry. A topoclimatological technique, in this study, which makes use of empirical relationships between the topography and the weather in Cheju Island was applied to produce reasonable estimates of monthly air temperatures over remote land area where routine observations are rare. Altitude values of the 250m grid points were first read from a 1 : 25000 topographic map. The mean altitude and other valuable topographical variables were then determined for each $1km^2$ land area. Daily minimum, maximum and mean air temperature data were collected from 19 points in Cheju Island from June 1987 to September 1988. The data were analyzed and grouped into 36 sets by type of air temperature and by month. Each of data set was regressed to the topographical variables to delineate empirical relationships between the local air temperature and the site topography. The total of 36 regression equations were finally selected and the equations were used to calculate the monthly air temperature for each $1km^2$ land area. The outputs were presented in a fine-mesh grid map with a 6-level contour capability.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.91-101
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• 2006

This study was conducted to analyze the relationships between distributions of major hardwood species and characteristics of topography in natural hardwood forest at Mt. Joongwang, Pyongchang-gun, Gangwon-do which belongs to mid-northern part of the temperate forest. Acer pictum var. mono, Acer manshuricum and Quercus mongolica were affected by elevation, while Ulmus davidiana var. japonica and Fraxinus rhynchophylla were affected by the change of slope. Importance values of A. pictum, Betula costata, Ulmus laciniata and Cornus controversa in valley were 13.41%, 5.68% and 3.29%, respectively, which were higher than in any other topography. Species diversity of valley was the highest with 0.98. Ratio of A. pictum and Q. mongolica in dominant species were 24% and 14%, respectively in valley, while were 19% and 23% in slop. Q. mongolica ratio in ridgeline was higher than any other species. Importance values of A. pictum increased continuously until elevation 1,200 m. importance values of F. rhynchophylla was 6.6% which was the highest value found on elevation 800 m. Distributions of major hardwood species were different according to the elevation. The ratio of Q. mongolica and A. pictum were 6.4%~17.5% and 6.0%~10.7% respectively, which were the highest ratio. Species diversity increased according to the increase of the elevation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.207-217
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• 2008

The SSTop (Sea Surface Topography) provides an estimate of the large scale structure of the deviations between the geoid height and the mean sea surface in terms of a normalized surface spherical harmonic series. The SSTop is the key information which has been used to determine the shape of earth, geoid, current and tide etc. Also, the SSTop is a basic source for the unification of vertical datums at the different height systems which were established according to the their respective purposes. In order to unify the vertical datum around the East-Asian (E-A) region (covers the area: $20^{\circ}-45^{\circ}N$ and $110^{\circ}-140^{\circ}E$), we estimated the value of SSTop in the E-A region using the predicted values of mean sea surface (from KMSS04) and geoid height (from EGM96 and EIGEN-GL04C) and analyzed to aspect of SSTop at 5 tidal stations (InCheon, JeJu, QingDao, Aburatsubo, KeeLung) with the estimated values of each station previously. The result from this study indicates that the SSTop in the E-A region is relatively stable except for the area around the Japanese and Ryukyu deep, and also shows that the distribution of values of SSTop is ranged from 40 to 60 cm at tidal stations except InCheon station.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.4
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• pp.469-476
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• 2009

The new laser scanning technology allows to attain 3D information faster with higher accuracy on surface ground, vegetation and buildings of the earth surface. This acquired information can be used in many areas after modifying them appropriately by users. The contour production for accurate landform is an advanced technology that can reveal the mountain area landscapes hidden by the trees in detail. However, if extremely precise LiDAR data is used in constructing the contour, massive-sized data intricates the contour diagram and could amplify the data size inefficiently. This study illustrates the algorithm producing contour that is filtered in stages for more efficient utilization using the LiDAR contour produced by the detailed landscape data. This filtering stages allow to preserve the original landscape shape and to keep the data size small. Point Filtering determines the produced contour diagram shape and could minimize data size. Thus, in this study we compared experimentally filtered contour with the current digital map(1:5,000).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.261-269
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• 1989

Agricultural activities in Chejudo require more specialized weather services in this region. The meteorological information available from the Korea Meteorological Service (KMS) is limited in its areal coverage because the KMS stations are located along the narrow band of coastal area. topoclimatological technique which makes use of empirical relationships between the topography and the weather can be applied to produce reasonable estimates of the climatic variables such as air temperature and precipitation over remote land area where routine observations are rare. Presentation of these estimates in a from of fine-mesh grid map can also be helpful to upgrade the quality of weather services in this region. Altitude values of the 250 m grid points were read from a 1: 25000 topographic map and the mean altitude, the mean slope, and the aspect of the slope were determined for each 1 km$^2$ land area from these altitude data. Daily minimum air temperature data were collected from 18 points in Chejudo during the winter period from November 1987 to February 1988. The data were grouped into 3 sets based on synoptic pressure pattern. Departures from the KMS observations were regressed to the topographical variables to delineate empirical relationships between the local minimum temperature under specific pressure patterns and the site topography. The selected regression equations were used to calculate the daily minimum temperature for each 1 km$^2$ land area under the specific pressure patterns. The outputs were presented in a fine-mesh grid map with a 6-level contour capability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.366-372
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• 2019

The PRISM model has been used to estimate precipitation in South Korea where observation data are readily available at a large number of weather station. However, it is likely that the PRISM model would result in relatively low reliability of precipitation estimates in North Korea where weather data are available at a relatively small number of weather stations. Alternatively, a hybrid method has been developed to estimate the precipitation distribution in area where availability of climate data is relatively low. In the hybrid method, Regression coefficients between the precipitation-terrain relationships are applied to a low-resolution precipitation map produced using the PRISM. In the present study, a hybrid approach was applied to North Korea for estimation of precipitation distribution at a high spatial resolution. At first, the precipitation distribution map was produced at a low-resolution (2,430m) using the PRISM model. Secondly, a deviation map was prepared calculating difference between altitudes of synoptic stations and virtual terrains produced using 270m-resolution digital elevation map (DEM). Lastly, another deviation map of precipitation was obtained from the maps of virtual precipitation produced using observation data from the synoptic weather stations and both synoptic and automated weather station (AWS), respectively. The regression equation between precipitation and terrain was determined using these deviation maps. The high resolution map of precipitation distribution was obtained applying the regression equation to the low-resolution map. It was found that the hybrid approach resulted in better representation of the effects of the terrain. The precipitation distribution map for the hybrid approach had similar spatial pattern to that for the existing method. It was estimated that the mean annual cumulative precipitation of entire territory of North Korea was 1,195mm with a standard deviation of 253mm.