• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.587-596
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• 2022

Sea levels are rising as a result of climate change, and low-lying areas along the coast are at risk of flooding. Therefore, we tried to investigate the relationship between sea level change and climate indices using satellite altimeter data (Topex/Poseidon, Jason-1/2/3) and southern oscillation index (SOI) and the Pacific decadal oscillation (PDO) data. If time domain data were converted to frequency domain, the original data can be analyzed in terms of the periodic components. Fourier transform and Wavelet transform are representative periodic analysis methods. Fourier transform can provide only the periodic signals, whereas wavelet transform can obtain both the periodic signals and their corresponding time location. The cross-wavelet transformation and the wavelet coherence are ideal for analyzing the common periods, correlation and phase difference for two time domain datasets. Our cross-wavelet transform analysis shows that two climate indices (SOI, PDO) and sea level height was a significant in 1-year period. PDO and sea level height were anti-phase. Also, our wavelet coherence analysis reveals when sea level height and climate indices were correlated in short (less than one year) and long periods, which did not appear in the cross wavelet transform. The two wavelet analyses provide the frequency domains of two different time domain datasets but also characterize the periodic components and relative phase difference. Therefore, our research results demonstrates that the wavelet analyses are useful to analyze the periodic component of climatic data and monitor the various oceanic phenomena that are difficult to find in time series analysis.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.405-412
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• 2022

This paper studies the method of estimating power loss and classifying the factors for improving the power generation efficiency through O&M. It is installed under various climatic conditions worldwide, operational and maintenance technologies suitable for the characteristics of the installation location are required. Existing studies related to solar power generation efficiency have been actively quantifying the impact on short-term losses by environmental factors such as high temperature, dust accumulation, precipitation, humidity, and wind speed, but analysis of the overall impact from a long-term operation perspective is limited. In this study, the potential for efficiency improvement was analyzed by re-establishing a loss classification system according to the power flow of solar power to derive a comprehensive efficiency model for long-term operation and estimating power loss through a case study for each region where climate conditions are classified. As a result of the analysis, the average annual potential for improving soiling loss was 26.9%, Death Valley 7.2%, and Seoul 3.8%. Aging losses was 6.6% in the 20th year as a cumulative. The average annual potential due to temperature loss was 2.9 % for Doha, 1.9% for Death Valley, and 0.2% for Seoul.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.402-412
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• 2022

This study investigated each forest's stand characteristics and the NVOCs emission characteristics for Quercus acuta, Castanopsis sieboldii, Dendropanax trifidus, Camellia Japonica which are major warm temperate evergreen broad-leaved species, and Pinus thunbergii. Data were collected from May 2019 to January 2020. The seasonal temperature and humidity of each research site indicated the typical climatic characteristics of Korea, which are hot and humid in summer and cold and dry in winter. Also, the atmospheric pressure was generally high in winter and higher in autumn and winter than in spring and summer. Overall, the total volume of NVOCs (Natural Volatile Organic Compounds) from the five research sites was the highest in the summer. The concentration of TNVOCs was relatively high in the Dendropanax trifidus forest in spring and winter, the Castanopsis sieboldii forest in the autumn, and the Quercus acuta forest in the summer. According to the results of this study, it was confirmed that the concentrations of NVOCs emission of warm temperate evergreen broad-leaved species such as Quercus acuta, Castanopsis sieboldii, Dendropanax trifidus and Camellia Japonica were not lower but rather higher than Pinus thunbergii. The correlation was positive (+) between NVOCs emission and temperature (r=0.590, P=0.000) or humidity (r=0.655, P=0.000), whereas it was negative (-) between NVOCs emission and atmospheric pressure (r=-0.384, P=0.000) or wind speed (r=-0.263, P=0.018). Among the micrometeological factors, humidity (β=0.507, P=0.000) was found to have the greatest effect on NVOC emission, followed by temperature, atmospheric pressure, and wind speed.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.316-323
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• 2022

Background: We developed a habitat suitability index (HSI) model for Pedicularis hallaisanensis, a Grade II Endangered Species in South Korea. To determine the habitat variables, we conducted a literature review on P. hallaisanensis with a specific focus on the associated spatial factors, climate, topography, threats, and soil factors to derive five environmental factors that influence P. hallaisanensis habitats. The specific variables were defined based on the collected data and consultations with experts in the field, with the validity of each variable tested through field studies. Results: Mt. Seorak had a suitable habitat area of 2.48 km² for sites with a score of 1 (0.62% of total area) and 0.01 km² for sites with a score of 0.9. Mt. Bangtae had a suitable habitat area of 0.03 km² for sites with a score of 1 (0.02% of total area) and 0 km² for sites with a score of 0.9. Mt. Gaya showed 0.13 km² of suitable habitat for sites with a score of 1 (0.17% of total area) and 0 km² for sites with a score of 0.9. Lastly, Mt. Halla showed 3.12 km² of suitable habitat related to sites with a score of 1 (2.04% of total area) and 4.08 km² of sites with a score of 0.9 (2.66% of total area). Mt. Halla accounts for 73.1% of the total core habitat area. Considering the climatic, soil, and forest conditions together with standardized collection sites, our results indicate that Mt. Halla should be viewed as a core habitat of P. hallaisanensis. Conclusions: The findings in this study provide useful data for the identification of core habitat areas and potential alternative habitats to prevent the extinction of the endangered species, P. hallaisanensis. Furthermore, the developed HSI model allows for the prediction of suitable habitats based on the ecological niche of a given species to identify its unique distribution and causal factors.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.4
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• pp.53-61
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• 2022

Growing agricultural products in greenhouses controlled by creating suitable climatic conditions and root zone of crop has been an important research and application subject. Appropriate environmental conditions in greenhouse are necessary for optimum plant growth improved crop yields. This study aimed to establish web-based remote monitoring system which monitors crops growth environment and status of crop on a real-time basis by applying to greenhouses IT technology connecting greenhouse equipment such as temperature sensors, soil sensors, crop sensors and camera. The measuring items were air temperature, relative humidity, solar radiation, CO₂ concentration, EC and pH of nutrient solution, medium temperature, EC of medium, water content of medium, leaf temperature, sap flow, stem diameter, fruit diameter, etc. The developed greenhouse monitoring system was composed of the network system, the data collecting device with sensors, and cameras. Remote monitoring system was implemented in a server/client environment. Information on greenhouse environment and crops is stored in a database. Items on growth and environment is extracted from stored information, could be compared and analyzed. So, A integrated monitoring system for smart greenhouse would be use in application practice and understanding the environment and crop growth for smart greenhouse management. sap flow, stem diameter and pant-water relations

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.259-272
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• 2022

Background: The Korean Peninsula exhibits a characteristic graded floral distribution, with northern (Manchurian flora) and southern (China-Japan-Korea flora) lineage species coexisting according to climatic and topographical characteristics. However, this distribution has been altered by climate change. To identify ecosystem changes caused by climate change and develop appropriate measures, the current ecological status of the entire Korean Peninsula should first be determined; however, analysis of the current floral distribution in North Korea has been hampered for political reasons. To overcome these limitations, this study constructed a database of floral distributions in both South and North Korea by integrating spatial information from the previously established National Ecological Survey in South Korea and geocoding data from the literature on biological distributions published in North Korea. It was then applied to analyze the current status and distribution characteristics of Manchurian and China-Japan-Korea plant species on the Korean Peninsula. Results: In total, 45,877 cases were included in the Manchurian and China-Japan-Korea floral distribution database. China-Japan-Korea species were densely distributed on Jeju-do and along the southern coast of the Korean Peninsula. The distribution density decreased as the latitude increased, and the distributions reached higher-latitude regions in the coastal areas compared with the inland regions. Manchurian species were distributed throughout North Korea, while they were densely distributed in the refugia formed in the high-elevation mountain regions and the Baekdudaegan in South Korea. In the current distribution of biomes classified according to the Whittaker method, subtropical and endemic species were densely distributed in temperate seasonal forest and woodland/shrubland biomes, whereas boreal species were densely distributed in the boreal forest biome Korean Peninsula, with a characteristic gradation of certain species distributed in the temperate seasonal forest biome. Factor analysis showed that temperature and latitude were the main factors influencing the distribution of flora on the Korean Peninsula. Conclusions: The findings reported herein on the current floral distribution trends across the entire Korean Peninsula will prove valuable got mitigating the ecological disturbances caused by ongoing climate change. Additionally, the gathered flora data will serve as a basis for various follow-up studies on climate change.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.428-434
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• 2022

This study was conducted to derive the site index of forest productivity of Robinia pseudoacacia (honey plant) to characterize suitable planting sites and to investigate the effect of the site environmental factors on the site index using the quantification theory I method. The data used in the analysis were growth factors (stand age, dominant height, etc.) of the 6th national forest resources survey and various site environmental factors of a forest soil map (1:5,000). The average site index value of the R. pseudoacacia stand in Korea was 14 (range, 8 to 18). The environmental factors affecting the site index were parent rock, climatic zone, soil texture, local topography, and altitude. The accuracy of the estimation model using quantification theory I was only 33%. However, the correlation between the site index and the site environmental factors was statistically significant at the 1% level. Results of quantification analysis between site index and site environmental factors revealed that metamorphic and igneous rocks received high grades as parent rocks, climate zones received higher grades than central temperate zone, clay loam and silt loam received high grades in soil texture, and hillside received a high grade in local topography. Analysis of the partial correlation between site topographical factors and forest productivity (site index) found that soil class and altitude were partially correlated to x by 0.4129 and 0.4023, respectively, indicating that these factors are the most influential variables.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.422-432
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• 2022

Soil and micro-climatic environmental monitoring was conducted to evaluate the factors causing tree growth impediments at the Baekdudaegan ecological axis restoration project site. As a result, it was found that the nutrient supply was insufficient in the restoration project site due to the lack of organic matter, total nitrogen and cation exchange capacity of the soil compared to the surrounding forest. After the completion of the restoration, the soil moisture in the autumn decreased more than 7 times faster than that of the surrounding forest, and it was evaluated that the soil moisture was significantly low due to the lack of silt and clay content. In the case of the restoration site, the annual potential evapotranspiration was analyzed to be 975mm, which is approximately two times higher than that of the surrounding forest. The soil moisture of the restoration site in the summer decreased rapidly during the daytime when the amount of insolation increased and this was found to be strongly influenced by the increase in potential evapotranspiration. In order to improve the above factors affecting the tree growth at the Baekdudaegan ecological axis restoration project site, it is necessary to induce the smooth supply of nutrients and water to plants by improving physical proprieties and cation exchange capacity, i.e., using litterfall, humus soil, soil conditioner and organic fertilizer. The results of this study are expected to serve as basic data for the design, construction, and management of ecological axis restoration projects in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.534-540
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• 1992

Climatic condition and seeding depth affect the seedling stand and early growth in the direct-seeded rice cultivation on dry soil. This experiment was conducted to elucidate the effects of the day /night temperatures and the seeding depths on the seedling emergence and mesocotyl elongation of rice seed. Three combinations of the day/night temperatures(25/2$0^{\circ}C$ 20/15$^{\circ}C$ and 20/1$0^{\circ}C$) were employed with seeding depths 1, 3, 5 and 7cm at the Phytotron of the Crop Experiment Station in 1991. It appeared that seedling emergence ratio increased and days to seedling emergence decreased in the high temperature (25/2$0^{\circ}C$) and the deep seeding depth (5 and 7cm) condition. The seedling emergence ratio did not. show the, difference up . to the seeding depths of 3cm and below, but the ratio decreased from the seeding depths of 5cm and above. Plant height and leaf number were almost the same up to the depths of 3cm at 30 days after seeding, but those of the seeding depths of 5cm and 7cm were remarkably reduced in all temperature combinations. Mesocotyl and lower internode elongation were seen in the high temperature(25/2$0^{\circ}C$) with the seeding depths of 5cm and 7cm. In the seeding depth of 6cm, of the tested varieties, Tamjinbyeo and Odaebyeo showed the highest emergence ratio. Generally, leaves of all tested varieties appeared approximately in the soil depth of 3cm, so the reasonable seeding depth will be around 3cm in the direct-seeded cultivation on dry soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.s01
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• pp.86-97
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• 1988

Sesame(Sesamum indicum L.) is probably the most ancient oilseed crop known in the world. The seed of sesame is used in a variety of ways as food. The whole seed may be eaten raw, either roasted or parched, or fed to birds and stock. Sesame oil is used as a salad or cooking oil, in shortening, margarine and in the manufacture of soap. Minor uses are as a fixative in the perfume industry and formerly as a carrier for fatsoluble substances in pharmaceuticals such as penicillin. One of the minor constituents of sesame oil, sesamin, is used for its synergistic effect in pyrethrin insecticides, in addition of a small quantity of this substance markedly increases the effectiveness of fly sprays. The meal remaining after oil extraction can be used as and animal feed-stuff or as manure. In general sesame meal is considered to be equal to cottonseed or soybean meal as a protein supplement for livestock and poultry. It is especially high in certain amino-acids such as methionine, which is low in soybean meal, and thus can be combined with it or similar meal to form a more balanced ration. An attempt to summarize the literature review on quality improvement of sesame was made to discuss the accomplishments of the past and perspectives in the future. The reviews on quality improvement of sesame were mainly discussed in connection with the cultural practices and genetic informations in current status. The emphasis focussed on environmental variation of quality in cultural practices, such as harvest time, variety by location, climatic condition, fertilizer application, and growth regulator treatment. On the genetic variation of quality, it was discussed on variety background, mutation breeding, correlations, and inheritance of quality related characteristics. It also was discussed on relationship between quality and plant traits, storage condition or period, and seed coat color. Moreover, current research status were reviewed on some minor elements such as sesamin, oxalic acid, and trypsin inhibitor. As a results of the review, the lack of an effort to quality improvement in each utilization area was indicated as a problem area. More active efforts for the improvement of quality were also insufficient to incorporate the available genes for quality in breeding method or collection and analysis of breeding materials. Therefore, researches in the future would be recommended to emphasize on these problem areas.