• Journal of Climate Change Research
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• v.4 no.3
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• pp.255-267
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• 2013

This study aims to reveal the relationship between major climatic factors and radial growth in Siu-ri, NamYangJuSi, Kyeonggido. To identify tree growth responses to climatic variation, we used correlation analysis after standardization and cross-dating of tree ring growth. We use the climatic data(monthly mean, minimum, maximum temperature and precipitation) from September of previous year to August of current year. In terms of relationship between mean, minimum, maximum temperature and tree ring growth, negative correlations were observed in September and October of the previous year. In case of Quercus mongolica, negative relationship were appeared in December of the previous year, January and February of present year. When it comes monthly maximum temperature, August and September of present year was negatively correlated with radial growth in the case of Pinus densiflora. We can conclude that reduced soil moisture due to high temperatures causes a water stress that stunts tree growth. In contrast, there are positive correlations in March of present year. These results suggest that high temperatures in March appear to prolong the growing season. Growth was positively correlated with precipitation from October to December of previous year and from May to September of present year. The results suggest that the smooth water supply from precipitation can promote the tree growth.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.405-417
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• 2022

The purpose of this study was to describe the photosynthetic features of Prunus maximowiczii and Prunus serrulate Lindl. var. pubescens (Makino) Nakai in response to drought stress. Specifically, we studied the effects of drought on photosynthetic ability and photosystem II activity. Drought stress (DS) was induced by cutting the water supply for 30 days. DS decreased the moisture contents in the soil, and between the 10th and 12th days of DS, both species had 10% or less of x., After the 15th day of DS, it was less than 5%, which is a condition for disease to start. We observed a remarkable decrease of maximum photosynthesis rate starting from 10th day of DS; the light compensation point was also remarkable. Dark respiration and net apparent quantum yield decreased significantly on the 15th day of DS, and then increased on the 20th day. In addition, the stomatal transpiration rate of P. maximowiczii decreased significantly on the15th day of DS, and then increased on the 20th day. Water use efficiency increased on the 15th day of DS, and then decreased on the 20th day. The stomatal transpiration rate of P. serrulate decreased significantly on the 20th day of DS, and then increased afterward, while its water use efficiency increased on the 20th day of DS, and then decreased afterward. These results indicate that the closure of stoma prevented water loss, resulting in a temporary increase of water use efficiency. Chlorophyll fluorescence analysis detected remarkable decreases in the functional index (PI_ABS) and energy transfer efficiency in P. maximowiczii after the 15th day of DS. Meanwhile, photosystem II activity decreased in P. serrulate after 20 days of DS. In addition, Ts-Ta, PI_ABS, DI_O/RC, ET_O/RC followed similar trends as those of the soil moisture content and photosynthetic properties, indicating that they can be used as useful variables in predicting DS in trees.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.747-763
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• 2022

Ocean salinity affects ocean circulation on a global scale and low salinity water around coastal areas often has an impact on aquaculture and fisheries. Microwave satellite sensors (e.g., Soil Moisture Active Passive [SMAP]) have provided sea surface salinity (SSS) based on the dielectric characteristics of water associated with SSS and sea surface temperature (SST). In this study, a Light Gradient Boosting Machine (LGBM)-based model for generating high resolution SSS from Geostationary Ocean Color Imager (GOCI) data was proposed, having machine learning-based improved SMAP SSS by Jang et al. (2022) as reference data (SMAP SSS (Jang)). Three schemes with different input variables were tested, and scheme 3 with all variables including Multi-scale Ultra-high Resolution SST yielded the best performance (coefficient of determination = 0.60, root mean square error = 0.91 psu). The proposed LGBM-based GOCI SSS had a similar spatiotemporal pattern with SMAP SSS (Jang), with much higher spatial resolution even in coastal areas, where SMAP SSS (Jang) was not available. In addition, when tested for the great flood occurred in Southern China in August 2020, GOCI SSS well simulated the spatial and temporal change of Changjiang Diluted Water. This research provided a potential that optical satellite data can be used to generate high resolution SSS associated with the improved microwave-based SSS especially in coastal areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.154-154
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• 2012

지표에서의 토양수분은 작은 구성비를 가짐에도 불구하고 여러 수문 현상을 연계하는 매우 중요한 인자로써 최근 관련 연구가 활발하게 진행되고 있다. 토양수분은 침투나 침루를 통하여 강우와 지하수를 연결하는 기능을 함과 동시에 강우사상에 따른 유출특성에 직접적인 영향을 미치며 증발산을 통하여 에너지 순환을 연결하는 중요한 기능을 한다. 토양수분을 측정하는 방법에는 세타 탐침(Theta Probe), 장력계, TDR(Time Domain Reflectrometry) 등이 이용되고 있으며, 광역 토양수분자료의 보다 정확한 공간 변동성의 관측을 위하여 항공원격탐사와 인공위성 원격탐사기술이 개발되어 적용되고 있다. 인공위성 영상은 자료의 분석이 간편하며, 공간자료이므로 공간 변화를 분석하는 데 있어 매우 편리하다. 그 중 MODIS(Moderate Resolution Imaging Spectroradiometer) 위성영상은 저해상도 영상으로 극궤도 위성인 Terra와 Aqua 위성에 장착되어 있으며, NASA에서 필요한 정보를 받아 사용할 수 있다. 본 연구에서는 유역의 물리적 지형자료와 같은 방대한 양의 자료 수집 없이도, 모형이 구축되면 인공위성자료와 강우자료만으로도 신뢰성 높은 결과를 단시간 내에 효율적으로 산정할 수 있는 자료 지향형 모형인 ANFIS(Adaptive Neuro-Fuzzy Inference System)를 사용하였다. 사용된 퍼지변수로는 시험유역의 토양수분 관측자료와 강수량 및 인공위성 자료인 MODIS NDVI(Normalize Difference Vegetation Index), MODIS LST(Land-Surface Temperature) 영상을 이용하였다. MODIS NDVI는 시간 해상도 8일, 공간해상도 250 인 Level 3 영상이며, MODIS LST는 시간 해상도 1일, 공간해상도 1 km인 Level 3 영상을 사용하였다. 위성자료를 사용하기 위해 Korea TM 좌표체계로 변환한 뒤, 토양수분 관측지점이 속한 각 셀의 속성값을 추출하였다. 위성자료와 수집된 자료 및 토양수분자료와의 관계를 분석하기 위하여 입력자료를 다양한 방법으로 구성하여 입력 변수를 생성하였다. 생성된 입력 변수와 ANFIS 모형을 연계하여 각각의 토양수분 산정모형을 구축하고 대상지점에 대한 토양수분을 산정 및 비교 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.605-605
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• 2016

최근 기후변화로 인한 국지적 또는 대규모 극한 가뭄과 홍수가 빈발함에 따라 수자원 관리 여건은 점점 더 어려워지고 있다. 이런 물 관련 재해에 보다 효과적으로 대응하기 위해서는 수자원인자에 대한 시공간적 모니터링이 필수적인데, 이러한 관점에서 시공간적 광역관측이 가능한 위성자료의 활용가치는 매우 높게 평가되고 있으며, 최근에는 국내외적으로 위성자료를 이용하여 수문 인자 산출, 가뭄 홍수 등의 모니터링 기술 등에 대한 연구가 활발히 진행되고 있다. K-water는 위성정보 활용기술력 축적을 통한 보다 효율적인 수자원 관리를 하기 위하여 수자원 분야에 활용 가능한 해외의 주요 위성자료를 실시간 직수신 처리하여 표출하는 K-water 위성영상관리시스템(K-SIMS, K-water Satellite Image Management System)을 2015년에 구축하였다. 현재 K-SIMS를 통해 관리되는 위성은 AQUA, TERRA, NPP, GCOM-W, GPM로서 총 5개이다. AQUA, TERRA, NPP 위성은 각 궤도운영 스케쥴에 따라 한반도 상공을 통과하는 시각에 안테나가 위성의 궤도를 따라가며 수신하고, GCOM-W, GPM 위성자료는 FTP 접속를 통해 준실시간으로 수신하고 있다. 산출물은 AQUA, TERRA, NPP가 각각 23종, GCOM-W 9종, GPM 2종 등 총 80여종으로 위성원시자료 수신즉시 처리 표출까지 실시간 자동 수행되고 있으나 식생지수, 강수, 구름, 대기온도, 수증기 등 대부분 수문기상학적 변수들로 구성되어 있어 수자원 관리 현업 업무에는 직접 사용하기에는 다소 한계가 있다. 따라서, 위성자료의 활용성을 높이기 위하여 수문해석에 중요한 변수인 토양수분에 대해서 AQUA, TERRA의 MODIS LST(Land Surface Temperature)와 식생지수(Vegetation Index)를 이용하여 SMI(Soil Moisture Index)를 산출하고 이를 K-SIMS에 표출하는 체계를 추가로 구축하여 현업 활용도가 높은 자료를 생산하고 있으며, 향후 위성자료를 활용한 가뭄지수를 추가로 산출하여 표출할 계획이다. 이와 함께 K-water는 차세대 중형위성 개발 사업에 따른 수자원 위성 확보에 대비해 수자원 분야 위성활용 중장기 계획을 마련하였다. 향후에 광학위성, SAR위성 등 다양한 위성자료의 융복합적 활용을 통하여 위성산출물 알고리즘을 지속적으로 개발함으로써 홍수, 가뭄, 수질 등 물 재해 대응 및 수자원 관리 전 분야에 위성자료의 활용을 확대해 나갈 계획이다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.11-11
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• 2020

Background : The genus Cypripediums are typically adapted to the low temperature and cold climates of the high land in Korea. The species which were reported in Korean peninsula are C.japonicum, C.macranthos, C.calceolus and C.guttatum. We had already reported the successful germination of the C.macranthos and C.guttatum. The small spotted lady's slipper orchid(C.guttatum) is most endangered plants to extinction of which population was reported less than 100 in Korea. The objective of the present research is restoration of the C.guttatum in ex situ and adaptation in high land and nursery. Methods and Results : The 350 seedlings of C.guttatum were transplanted in soil at alpine area(altitude 750m) and the nursery of Korea National Arboretum(KNA) in YangPyeong city on May 2019 and 2020 in order to verify the possibility of ex situ restoration. The sprouted ratio of the seedlings were less than 10% in the alpine area and 83% in the nursery of KNA. The reasons of the diverse survival ratio are presumed as the low moisture content in the soil and heavy shade of the alpine area. The 15 cypripedium species and 29 hybrids were also effectively adapted in the KNA rare plant garden. Conclusion : These results demonstrated the difficulties of the restoration for small spotted lady's slipper orchid in the natural habitation. From the above results, we may conclude that the critical factors of the genus Cypripedium are intensive care for the fragile seedlings during the 1^st year acclimatization.

• Korean Journal of Plant Resources
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• v.13 no.3
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• pp.188-194
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• 2000

This study was carried out to obtain the optimum cultivation conditions of wild ornamental plant resources, Dicentra spectabilis L. The altitude of the habitat was ranged from 630m to 690m in Mt. Gujeol. Most of the habitat faced toward the northeast aspect and the gradient was ranged from 25 to 33 degrees. The light intensity of Dicentra community was 14,000lux on the average, and it was tendency to decrease by foliation of other woody plants. The appearance number of Dicentra per quadrat was 30 individuals on the average, and total appearance species in all quadrat surveyed was 52 taxa. Among them, Quercus mongolica, Lindera obtusiloba, Corylus heterophylla, Cornus controversa, woody plants, Corydalis speciosa, Pseudostellaria heterophylla, Artemisia keiskeana, Dryopteris crassirhizoma, Arisaema amurense var. serratum, Carex siroumensis, and Chloranthus japonicus, herbaceous plants, were showed as dominant species. Soil acidity in the habitat was 5.15 to 5.96, and average content of soil moisture was 32.6%. The contents of average organic matter, $P_2O_5$, K, Ca, and Mg were 1.99%, 14mg/kg, 0.55me/100g, 15.2me/100g, and 3.3me/100g, respectively. Electron conductivity was ranged from 0.50 to 0.76dS/m. Also, the average air temperature of May and June was 14.2$^{\circ}C$ and 19.4$^{\circ}C$, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.192-199
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• 1991

To manufacture a good organic fertilizer through rapid composting process, cow dung was mixed with bulking materials such as rice straws, shredded bark, wood chips, and saw dust. The mixing ratio of the cow dung and bulking material was two to one on volume basis and moisture content was adjusted to 60 to 70 percent, C/N ratio 25 to 30 and aeration forced with suction during the aerated pile fermentation. Aerated pile was established outdoors and curing pile was in vinylhouse and the experiment was conducted for 3 years from '88 to '90. After pilling, temperature in aerated pile was reached to the maximum level at 7 to 9 days and the temperatures of cow dung + shredded bark, cow dung + wood chips, and cow dung + rice straws were higher than that of cow dung, and cow dung + saw dust. Total carbon, and C/N ratio in aerated pile fermentation period were increased in the middle stage and then they were decreased with the process of days, and nutrient contents in curing pile period had the same tendency as in the aerated pile.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1032-1036
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• 2012

A bulking agent is an essential material for composting of high-moisture livestock manure such as pig slurry. Sawdust has been used as the most popular bulking agent but resources are limited in Korea. In this study, the feasibility of rice hull as a bulking agent was examined for composting of solid pig manure. The solid pig manure was mixed with 15% sawdust (PM+SD15), 15% rice hull (PM+RH15), 10% sawdust and 5% rice hull (PM+SD10+RH5), and 5% sawdust and 10% rice hull (PM+SD5+RH10) based on fresh weight. These mixtures were composted for 35 days. The average temperature of the composting file for 35 days was higher in PM+SD10+RH5 and PM+SD5+RH10 than in PM+SD15 and PM+RH15. The mass loss of PM+SD10+RH5 and PM+SD5+RH10 were 36.7 and 36.4%, respectively, which were higher than that of PM+SD15 and PM+RH15. After composting, organic matter content and organic matter/nitrogen ratio in all treatments met the official standards of commercial fertilizers. We concluded that rice hull may be a good bulking agent for pig manure composting when it is used in mixture with sawdust.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.29-39
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• 2017

To compare the features of ground-dwelling invertebrates according agroecosystems, we selected paddy fields, dry fields, orchards in the Eastern region of Korea. The surveys were performed by using pit-fall traps twice per year from 2013 to 2015. Total 6,420 individuals of 172 species belonging to 13 orders, 58 families were investigated in the Eastern region, the species of Hymenoptera (38.26%), Orthoptera (16.28%) accounted large portion of the communities. In the geographical observation, invertebrates were caught was 2,983 individuals in Gyeongsangnam-do, the diversity index of Gyeongsangbuk-do community was higher than of the others and abundance and species richness of paddy field were higher than from dry field or orchard. To understand the relation between taxonomic groups and environmental factors, we carried out the canonical correspondence analysis and hierarchical clustering. As a result, Homoptera, Blattaria, Isoptera, and Coleoptera were positively related to soil pH, soil temperature, and moisture contents, and negatively related to the others. Invertebrate community also were patterned dependently by type of ecosystems. This results were shown that distribution of invertebrates is a few influenced the relationship of the space habituated invertebrates and environmental factors.