• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.71-85
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• 2012

The purpose of this study is to estimate air purification effectiveness considering the improvement of its methods related atmospheric environment. The air purification effectiveness is estimated in Daegu, one out of Korean Metropolitan cities because air pollution is getting serious in a heavily urbanized area. The absorption of pollutants is calculated by considering spatial heterogeneity that was not considered previous studies and the spatial resolution of air dispersion modeling is also improved by kriging method. According to the type and distribution of urban forest, total 26 kinds of plant communities were distributed with Pinus densiflora community, Pinus densiflora-Quercus mongolica community, Pinus densiflora-Quercus acutissima community and other kinds of communities in the study area. In the results of estimating the $CO_2$ absorption amount for identification of the air purification effectiveness on urban forest, the annual absorption amount was total 108,155t/yr. Also, the annual absorption amounts of $NO_2$ and $SO_2$ were total 183.5 ton and 410.2 ton respectively. The findings from this study can confirm the differences of pollutant absorption by concentration that could not identify if spatial distribution of pollutant concentration had not been considered.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.3
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• pp.191-200
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• 2013

This study was conducted to examine the geographic variation of bud phenology of Zelkova serrata provenances. Data were collected from Gangneung, Yilmsil, Hwaseong and Jinju plantations which were parts of the 6 provenance trials established by Korea Forest Research Institute in 2009. The 16 provenances were included in these trials. The starting date of bud burst and finishing date of leaf expansion were investigated from April to May every other day. The four geographic factors and fifteen climatic factors of the test sites and provenances were considered in this study. Canonical correlation analysis was conducted to examine the major factors affecting the bud phenology between test sites and provenances. The study results suggested that the major factors affecting the timing of bud burst were the differences of extremely high temperature (March-October), annual mean temperature, mean temperature (March-October), extremely high temperature (July-August) and mean humidity (June-October) between test site and provenance. The provenances with lower mean or high temperature than those of plantation showed the earlier bud burst and leaf expansion. It showed a typical north-south or low-high temperature cline. Finally, we discussed the implication of the tree breeding program of Z. serrata based on these results.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.520-529
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• 2012

Geographic distribution and species composition of phytoplankton were investigated in Jinhae Bay for 12 months. Total 158 species were found including 95 bacillariophyceae, 58 dinophyceae, 1 euglenoids, and 4 dictyochaceae. The total cell numbers of phytoplakton ranged from $4.0{\times}10^3{\sim}9.0{\times}10^7\;cells{\cdot}L^{-1}$. Highest and lowest amounts of cells were found in July (Chl.a 13.19 $mg{\cdot}m^{-3}$) and March(Chl.a 3.44 $mg{\cdot}m^{-3}$), respectively. Leptocylindrus danicus and Pseudo-nitzschia spp. were dominant in spring, and Dactliosolen fragilissimus and Pseudo-nitzschia spp. were dominant in summer. Chaetoceros spp. and Skeletonema spp. were domonant in autumn and winter. The amounts of nitrogen and phosphorus were also measured during the survey. Higher ratio of nitrogen (DIN : DIP = 28 : 1) was found in the east Jinhae Bay compared to the ratio of the west Jnhae Bay that showed 14 : 1 of N : P ratio. The total amounts of nitrogen, phosphorus and Chl.a were also higher in the east Jinhae Bay compared to the west area. The geographic differences between the east and west of Jinhae Bay were also discussed along with phytoplankton compostion.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.85-99
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• 2020

Reservoir is an important infrastructure of our society because it can store immense amount of water for various usages - manufacturing, agriculture, drinking, power generation, tourism etc. For maintenance of reservoir, various efforts in administrative and technological aspects are periodically conducted and monitoring the conditions of reservoir bed is the first priority for maintenance of reservoir. To check the conditions of reservoir bed, we measured depth of reservoir by using echo sounder, which is relatively reliable, prior to discharging of stored water and surveyed topography of reservoir by using UAV after discharging of water. Then, we conducted interpolation of measured depth of water by means of inverse distance weighting interpolation, Kriging interpolation, minimum curvature interpolation and radial basis function interpolation and calculated the volume of reservoir for each interpolation method. We compared the calculated volume of reservoir with the volume of water calculated by UAV after discharging of water and found the following results: First, as results of the above processes, we found that the Kriging interpolation was 97% correct in measurement of the volume of reservoir. Second, as results of comparison of differences between topographical areas and interpolated areas after selection of cross section for comparison, Kriging interpolation was found to have the most similar configuration with the topographical configuration by showing the least difference in the area of cross section. Therefore, it is determined that the optimal modeling of reservoir bed with the water depth data measured by echo sounder shall provide basic information for efficient maintenance of reservoir.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.45-59
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• 2006

In this study, the effects of the surface topographical characteristics on the meteorological fields are examined in a mesoscale meteorlolgical model. We calculated the direct solar radiation using the illumination angle considering the inclination of topography and tried to find out its effect on meteorological fields. In above experiments, we selected two cases for the clear day and the cloudy day to show the effect of weather and represented the results for two cases. In the correction of the direct solar radiation, the results of two cases indicate that there are obvious differences on the steep Taeback and Soback mountains. And on the time-series analysis the east-facing slope of these mountains receives the more direct solar radiation about $10-60W/m^2$ in the morning hours but lesser in the afternoon hours than the horizontal surface while it is opposite on the west-facing slope. And the results mentioned above are more obvious at clear day. With the same analysis method, at clear day, the surface skin temperature is higher at all hours than that on horizontal surface on the both of slope. At cloudy and rainy day, the surface skin temperature on the east-facing slope is higher in the morning hours but lower in the afternoon hours than that on horizontal surface. But on the west-facing slope, it is higher at all hours than that on horizontal surface. In the two cases, the temperature considering the slope of surface is almost higher than that on the horizontal surface. The wind is stronger than that on the horizontal surface with increasing pressure gradient force according as increasing temperature gradient around the Taeback and the Soback mountains.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.90-103
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• 2012

Mallipo is a representative beach contaminated by Hebei Spirit oil spill accident in December 2007. This study aims to compare the differences of two seasons (winter and summer) for the spatio-temporal variation patterns of oiling status in the whole area and divided five regions of Mallipo beach. In the whole area, the decreasing rate of average TPH (total petroleum hydrocarbon) in winter was twice greater than summer during four years. According to the spatial variation pattern analysis of oiling status using weighted mean center and weighted standard distance, the oil concentration was clustered on southwestern region in winter, however, the TPH was dispersed in the whole area in summer. Temporal variation pattern of TPH in each of Mallipo's five regions showed that TPH had been consistently decreased in winter, but oil concentration had not been changed in summer since 2009 except the southwestern region. Therefore, in order to evaluate and predict the progress of oiling status, it is needed to analyze the spatio-temporal variation pattern of TPH using spatial analysis after separating data into seasons (e.g., winter and summer). In addition, time series analysis is useful in the regional scales through spatial partitioning rather than the whole beach area for the understanding of temporal variation pattern.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.157-169
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• 2010

In this study, the applicability of SRTM(The Shuttle Radar Topography Mission) DEM(Digital Elevation Model) which is one of the remotely sensed shuttle's radar digital elevation was tested for use as the input data in a grid-based rainfall-runoff model. The SRTM DEM and digital topographic map derived DEM(TOPO DEM) were building with 500m spatial resolution for the Chungju-Dam watershed which located in the middle east of South Korea, and stream-burning method was applied to delineate the proper flow direction for model application. Similar topographical characteristics were shown as a result of comparing elevation, flow-direction, hydrological slope, number of watershed cell, and profile between SRTM DEM and TOPO DEM. Two DEMs were tested by using a grid-based rainfall-runoff model named KIMSTORM with 6 storm events. The results also showed no significant differences in average values of relative error for both peak runoff(0.91 %) and total runoff volume(0.29 %). The results showed that the SRTM DEM has applicability like TOPO DEM for use in a grid-based rainfall-runoff modeling.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.169-185
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• 2016

Recently mean stand height has been added as new attribute to forest type maps, but it is often too costly and time consuming to manually measure 9,100,000 points from countrywide stereo aerial photos. In addition, tree heights are frequently measured around tombs and forest edges, which are poor representations of the interior tree stand. This work proposes an estimation of mean stand height using an image-based point cloud, which was extracted from stereo aerial photo with FUSION S/W. Then, a digital terrain model was created by filtering the DSM point cloud and subtracting the DTM from DSM, resulting in nDSM, which represents object heights (buildings, trees, etc.). The RMSE was calculated to compare differences in tree heights between those observed and extracted from the nDSM. The resulting RMSE of average total plot height was 0.96 m. Individual tree heights of the whole study site area were extracted using the USDA Forest Service's FUSION S/W. Finally, mean stand height was produced by averaging individual tree heights in a stand polygon of the forest type map. In order to automate the mean stand height extraction using photogrammetric methods, a module was developed as an ArcGIS add-in toolbox.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.2
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• pp.34-43
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• 2018

DEM(Digital Elevation Model) being fundamental data in geospatial domain is produced from different data and using various methods. As they are derived their precision varies and altering derivative in application. In this work, we compare two widely used DEMs namely(Advanced Land Observing Satellite World 3D 30m and Shuttle Radar Topography Mission Global 30m) around coastal islands in Gyeongsangnam-do, South Korea. First statistics of each DEM were calculated and later overlapped in Landsat image for visual comparison of areas below and above zero-meter elevation. As a result, it was found that DEMs were highly correlated with each other and had similar statistics. Besides having few high differences in hilly land area, they were able to represent the coastal lines. It has also been noted that they have many negative values and should carefully select study area covering full watershed in coastal regions to avoid negative elevation even after filling the sinks.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.90-103
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• 2017

This study analyzed the surface temperature characteristics of urban green spaces under high summer temperatures to clarify the functions of green spaces in reducing urban temperatures. We obtained accurate surface temperature data using highresolution unmanned aerial vehicle images of the survey site, which was an isolated green space in the city. We analyzed differences in the surface temperature by land cover type, vegetation type, species type, and the relationship between surface temperature and vegetation volume. Based on the results, among the land cover types, wetlands and forests had low temperatures and paving areas had very high temperatures. Regarding vegetation type, broad-leaved trees had lower temperatures than coniferous trees in forests. However, in planted areas, coniferous trees had lower temperatures than broad-leaved trees. The temperature of long grass was higher than that of short grass, which suggested that the volume of grass affected the temperature. Regarding forest species type, the temperature of broad-leaved Robinia pseudoacacia forest and mixed broad-leaved forest was lower than coniferous Pinus densiflora forest. There was a slight difference in temperature between R. pseudoacacia forest and mixed broad-leaved forest. The analysis of the relationship between vegetation volume and temperature by forest species type indicated a negative correlation, where the temperature decreased with increasing vegetation volume, similar to the results of previous studies. However, we found a weak positive correlation in R. pseudoacacia forest; therefore, an increase in volume may not reduce the surface temperature depending on the dominant species.