• Korean Journal of Remote Sensing
• /
• v.35 no.4
• /
• pp.617-623
• /
• 2019

Numerous water disasters have recently occurred all over the world, including South Korea, due to global climate change in recent years. As water-related disasters occur extensively and their sites are difficult for people to access, it is necessary to monitor them using satellites. The Ministry of Environment and K-water plan to launch the next-generation medium satellite No. 5 (water resource/water disaster satellite) equipped with C-band synthetic aperture radar (SAR) in 2025. C-band SAR has the advantage of being able to observe water resources twice a day at a high resolution both day and night, regardless of weather conditions. Currently, RADARSAT-2 and Sentinel-1 equipped with C-band SAR achieve the purpose of their launch and are used in various environmental fields such as forest structure detection and coastline change monitoring, as well as for unique purposes including the detection of flooding, drought and soil moisture change, utilizing the advantages of SAR. As such, this study aimed to analyze the characteristics of the next-generation medium satellite No. 5 and its application in environmental fields. Our findings showed that it can be used to improve the degree of precision of existing environmental spatial information such as the classification accuracy of land cover map in environmental field works. It also enables us to observe forests and water resources in North Korea that are difficult to access geographically. It is ultimately expected that this will enable the monitoring of the whole Korean Peninsula in various environmental fields, and help in relevant responses and policy supports.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.24 no.1
• /
• pp.25-36
• /
• 2021

The honey bee has a crucial ecological status for maintaining the natural ecology system. Pollination mediations by honey bees are recognized as an efficient way to enhance the quality of biological diversity and green areas in the nature and the urban ecological system. However, the population of bee around the world is decreasing and we do not know exactly how bees react to the physical environment in the urban area. This study is a basic research for the improvement of pollination services in the Korean urban ecological system. It aims to induce and review environmental variables which have high relations with the activities of pollination mediation insects in the urban area. The study established a Maxent model using five urban environmental variables that reflect the ecology of Bombus ignitus and the place information where Bombus ignitus appears in 18 spots of Seoul city, and compared with previous research results on Apis millifera. Bombus ignitus preferred places with more natural environments such as mountain forest areas and vicinities of streams. They preferred Stratified Tree Area the most among the vegetation types existing in the urban area. Comparing chicken models, both species saw their response value drop as the building coverage rose. In the case of Apis millifera and Bombus ignitus variables, the response value of both species was high in 10 out of 20 types. The result of this study is expected to provide basic information for improving the pollination services in the Korean urban area and to be utilized as the basic materials for the future urban planning.

• Korean Journal of Remote Sensing
• /
• v.38 no.1
• /
• pp.83-101
• /
• 2022

Accurate atmospheric correction is essential for the analysis of land surface and environmental monitoring. Aerosol optical depth (AOD) information is particularly important in atmospheric correction because the radiation attenuation by Mie scattering makes the differences between the radiation calculated at the satellite sensor and the radiation measured at the land surface. Thus, it is necessary to use high-quality AOD data for an appropriate atmospheric correction of high-resolution satellite images. In this study, we examined the Second Simulation of a Satellite Signal in the Solar Spectrum (6S)-based atmospheric correction results for the Sentinel-2 images in South Korea using raster AOD (MODIS) and single-point AOD (AERONET). The 6S result was overall agreed with the Sentinel-2 level 2 data. Moreover, using raster AOD showed better performance than using single-point AOD. The atmospheric correction using the single-point AOD yielded some inappropriate values for forest and water pixels, where as the atmospheric correction using raster AOD produced stable and natural patterns in accordance with the land cover map. Also, the Sentinel-2 normalized difference vegetation index (NDVI) after the 6S correction had similar patterns to the up scaled drone NDVI, although Sentinel-2 NDVI had relatively low values. Also, the spatial distribution of both images seemed very similar for growing and harvest seasons. Future work will be necessary to make efforts for the gap-filling of AOD data and an accurate bi-directional reflectance distribution function (BRDF) model for high-resolution atmospheric correction. These methods can help improve the land surface monitoring using the future Compact Advanced Satellite 500 in South Korea.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.9
• /
• pp.1195-1208
• /
• 2022

Silver nanoparticles (AgNPs) have potential applications in medicine, photocatalysis, agriculture, and cosmetic fields due to their unique physicochemical properties and strong antimicrobial activity. Here, AgNPs were synthesized using actinobacterial SL19 strain, isolated from acidic forest soil in Poland, and confirmed by UV-vis and FTIR spectroscopy, TEM, and zeta potential analysis. The AgNPs were polydispersed, stable, spherical, and small, with an average size of 23 nm. The FTIR study revealed the presence of bonds characteristic of proteins that cover nanoparticles. These proteins were then studied by using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and identified with the highest similarity to hypothetical protein and porin with molecular masses equal to 41 and 38 kDa, respectively. Our AgNPs exhibited remarkable antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. The combined, synergistic action of these synthesized AgNPs with commercial antibiotics (ampicillin, kanamycin, streptomycin, and tetracycline) enabled dose reductions in both components and increased their antimicrobial efficacy, especially in the case of streptomycin and tetracycline. Furthermore, the in vitro activity of the AgNPs on human cancer cell lines (MCF-7, A375, A549, and HepG2) showed cancer-specific sensitivity, while the genotoxic activity was evaluated by Ames assay, which revealed a lack of mutagenicity on the part of nanoparticles in Salmonella Typhimurium TA98 strain. We also studied the impact of the AgNPs on the catalytic and photocatalytic degradation of methyl orange (MO). The decomposition of MO was observed by a decrease in intensity of absorbance within time. The results of our study proved the easy, fast, and efficient synthesis of AgNPs using acidophilic actinomycete SL19 strain and demonstrated the remarkable potential of these AgNPs as anticancer and antibacterial agents. However, the properties and activity of such particles can vary by biosynthesized batch.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1D
• /
• pp.203-209
• /
• 2006

SAR (Synthetic Aperture Radar) technology, which is not influenced by cloud cover because of using electromagnetic wave of long wavelength, has an advantage in mapping the earth. NASA, recognizing these strong points of SAR, launched SRTM (Shuttle Radar Topography Mission), and acquired the topographic information of the earth. SRTM and NED (National Elevation Data) of USGS were used for the research and vegetation height map was produced through differentiating the two data. Correlation between SRTM-NED and planting year was analyzed to see the relationship. Strong correlation was detected and it shows the feasibility of estimating timber age and eventually creating timber age map from SRTM-NED. Additional analyses were conducted to check if the linearity is influenced by regional characteristics and forest uniformity. As results, the correlation between SRTM-NED and timber age is influenced by roughness of the terrain. Overall, this paper shows that timber age estimation using SRTM and NED can be sufficiently practical.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.1
• /
• pp.57-72
• /
• 2018

Time series analysis of tower flux measurement can be used to build quantitative evidence for the achievement of climate-smart agriculture (CSA). In this study, we have assessed the first objective of CSA (regarding ecosystem productivity and efficiency) for rice paddy-dominated heterogeneous farmland. A set of quantitative indicators were evaluated by analysing the time series data of carbon, water and energy fluxes over the Haenam farmland site in Korea (HFK) during the rice growing seasons from 2003 to 2015. Four different varieties of rice were cultivated during the study period in chronological order of Dongjin No. 1 (2003-2008), Nampyung (2009), Onnuri (2010-2011), and Saenuri (2012-2015). Overall at HFK, gross primary productivity (GPP) ranged from 800 to $944g\;C\;m^{-2}$, water use efficiency (WUE) ranged from 1.91 to $2.80g\;C\;kg\;H_2O^{-1}$, carbon uptake efficiency (CUE) ranged from 1.06 to 1.34, and light use efficiency (LUE) ranged from 0.99 to $1.55g\;C\;MJ^{-1}$. Among the four rice varieties, Dongjin No. 1-dominated HFK showed the highest productivity with higher WUE and LUE, but comparable CUE. Considering the heterogeneous vegetation cover at HFK, a rule of thumb comparison suggested that the productivity of Dongjin No1-dominated HFK was comparable to those of monoculture rice paddies in Asia, whereas HFK was more efficient in water use and less efficient in carbon uptake. Saenuri-dominated HFK also produced high productivity but with the growing season length longer than Dongjin No.1. Although the latter showed better traits for CSA, farmers cultivate Saenuri because of higher pest resistance (associated with adaptability and resilience). This emphasizes the need for the evaluation of other two objectives of CSA (i.e. system resilience and greenhouse gas mitigation) for complete assessment at HFK, which is currently in progress.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.5 no.2
• /
• pp.136-142
• /
• 1985

For better grassland development in the forest, this field experiment was carried out to investigate the effect of thirteen different fertilizer levels of nitrogen(N), phosphorus ($P_2O_5$) and potassium ($K_2O$) on the botanical composition, growth and dry matter yield of grass-clover mixtures grown under trees with 40-50% of shading level. This experiment was arranged as a randomized block design with replications, and performed on the experimental field in the suburban forest of Suweon in 1984. The results obtained are summarized as follows: 1. Plant height and cover degree of grasses found to be high with 28 and 42kg N fertilizer per 10a, while those were the lowest with zero and N-zero fertilizer levels. The degree of bare land after the fourth cut was also high in the low N level. 2. A significant higher degree of leaf green and chlorophyll content of leaf blade was observed in the plot of 28 and 42 kg N per 10a when compared with low N fertilizer plot. However, leaf decay and plant type of grasses tended to be a little poor as the high N was applied. 3. the regrowth plant length and dry weight of grasses after the first cut increased significantly with 28 and 42 kg N fertilizer. However, those showed slightly increased regrowth in the plot of zero and N-zero fertilizer levels. 4. The dry matter yield of grasses was higher with 28 and 42 kg N than that of low N fertilizer level. Higher yields were obtained in the plot of standard ($N-P_2O_5-K_2O$=28-20-24 kg/10a), 50% increase of $N,P_2O_5K_2O$ and N-50% increase, although there were no significant differences among three fertilizer levels. 5. Growth, botanical composition, regrowth and yield of grasses grown under pine trees were significantly influenced by N fertilizer level, regardless of $P_2O_5\;and\;K_2O$. The fertilizer level of $N-P_2O_5-K_2O$ was 28-20-24 kg per 10a for more forage production in the forest. Considering economic yield in this study, however, the optimum fertilizer level of N, $P_2O_5\;and\;K_2O$ was suppose to be 21-28, 10-15, and 12-18kg per 10a, respectively.

• Journal of the Korean Geographical Society
• /
• v.38 no.4
• /
• pp.630-639
• /
• 2003

This study aims to analysis the distribution and change of cropland and forest, the Onseong, Saebyeol, and Eundeok counties on the lower reach of Duman(Tumen) river, northeast Korea, using 1992 year Landsat TM data, 2000 year Landsat ETM data, and digital terrain elevation data(DTED). Land cover and land use of the study areas are classified into cropland, forest, village, and water body, using the supervised classification method including 1:50,000 DTED analysis, image band composition, and principal component analysis(PCA). Results of quantitative analysis present that each growth rate of cropland of Onseong and Eundeok are 22.8% and 14.7% corresponding to decreasing rates of forest, 8% and 13.6% during 8 years from 1992 to 2000. In Onseong, Saebyeol, and Eundeok, each values of mean elevations and slope gradients increased to 192m, 95m, and 91m from 157m, 85m, and 78m, and to 6.6$^{\circ}$, 3.0$^{\circ}$, and 4.4$^{\circ}$ from 5.2$^{\circ}$, 2.5$^{\circ}$, and 3.0$^{\circ}$. Especially, in case of newly developed cropland, the values of mean elevation and mean gradient have 225m, 122m, and 127m, and 9.4$^{\circ}$, 5.1$^{\circ}$, and 8.0$^{\circ}$, in above three regions. These new croplands were developing along to deeper valleys and toward lower hill and mountain slope up to knickpoint zone of gradient change. Deforested lands for cropland have formed irregular pattern of patch-type, and become sources for the sheet erosion, rilling and gulleying in mountain slope and sedimentation in local river channel. Though there were no field checking, analysis using landsat images and GIS mapping can help understand actual environmental problems relating to cropland development of mountain slope in North Korea.

• Ecology and Resilient Infrastructure
• /
• v.7 no.4
• /
• pp.227-237
• /
• 2020

Microclimatic data were measured, and the human thermal sensation was analyzed at 10 local climate zones based on the major land cover classification to investigate the thermal environment of urban areas during summer nighttime. From the results, the green infrastructure areas (GNIAs) showed an average air temperature of 1.6℃ and up to 2.4℃ lower air temperature than the gray infrastructure areas (GYIAs), and the GNIAs showed an average relative humidity of 9.0% and up to 15.0% higher relative humidity. The wind speed of the GNIAs and GYIAs had minimal difference and showed no significance at all locations, except for the forest location, which had the lowest wind speed owing to the influence of trees. The local winds and the surface roughness, which was determined based on the heights of buildings and trees, appeared to be the main factors that influenced wind speed. At the mean radiant temperature, the forest location showed the maximum value, owing to the influence of trees. Except at the forest location, the GNIAs showed an average decrease of 5.5℃ compared to GYIAs. The main factor that influenced the mean radiant temperature was the sky view factor. In the analysis of the human thermal sensation, the GNIAs showed a "neutral" thermal perception level that was neither hot nor cold, and the GYIAs showed a "slightly warm" level, which was a level higher than those of the GNIAs. The GNIAs showed a 3.2℃ decrease compared to the GYIAs, except at the highest forest location, which indicated a half-level improvement in the human thermal environment.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.24 no.1
• /
• pp.48-61
• /
• 2022

South Korea is quite vegetation rich country which has 63% forests and 16% cropland area. Massive NOx emissions from megacities, therefore, are easily combined with BVOCs emitted from the forest and cropland area, then produce high ozone concentration. BVOCs emissions have been estimated using well-known emission models, such as BEIS (Biogenic Emission Inventory System) or MEGAN (Model of Emission of Gases and Aerosol from Nature) which were developed using non-Korean emission factors. In this study, we ran MEGAN v2.1 model to estimate BVO Cs emissions in Korea. The MO DIS Land Cover and LAI (Leaf Area Index) products over Korea were used to run the MEGAN model for June 2012. Isoprene and Monoterpenes emissions from the model were inter-compared against the enclosure chamber measurements from Taehwa research forest in Korea, during June 11 and 12, 2012. For estimating emission from the enclosed chamber measurement data. The initial results show that isoprene emissions from the MEGAN model were up to 6.4 times higher than those from the enclosure chamber measurement. Monoterpenes from enclosure chamber measurement were up to 5.6 times higher than MEGAN emission. The differences between two datasets, however, were much smaller during the time of high emissions. More inter-comparison results and the possibilities of improving the MEGAN modeling performance using local measurement data over Korea will be presented and discussed.