• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.240-249
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• 2005

The normal Indian Ocean is characterized by warmer waters over the eastern region and cooler waters over the western region. Changes in sea surface temperature (SST) over the western and eastern Indian Ocean give birth to a phenomenon now referred to as the Indian Ocean Dipole Mode (IODM). The positive phase of this mode is characterized by positive SST anomalies over the western Indian Ocean and negative anomalies over the southeastern Indian Ocean, while the negative phase is characterized by a reversed SST anomaly pattern. On the other hand, the normal Pacific Ocean has warm (cool) waters over the western (eastern) parts. Positive (negative) SST anomalies over the central/eastern (western) Pacific Ocean characterize the E1 Nino phenomenon. The reverse situation leads to the La Nina phenomenon. The coupled ocean-atmosphere phenomenon over the Pacific is referred to as the E1 Nino Southern Oscillation (ENSO) phenomenon. In this study the impact of IODM and ENSO on the East Asian monsoon variability has been studied using observational data and using the Community Atmospheric Model (CAM) of the National Center for Atmospheric Research (NCAR). Five sets of model experiments were performed with anomalous SST patterns associated with IODM/ENSO superimposed on the climatological SSTs. The empirical and dynamic approaches reveal that it takes about 3-4 seasons fur the peak IODM mode to influence the summer monsoon activity over East Asia. On the other hand, the impact of ENSO on the East Asian monsoon could occur simultaneously. Further, the negative (positive) phase of IODM and E1 Nino (La Nina) over the Pacific enhances (suppresses) monsoon activity over the Korea-Japan Sector. Alternatively, IODM appears to have no significant impact on monsoon variability over China. However, El Nino (La Nina) suppresses (enhances) monsoon activity over China. While the IODM appears to influence the North Pacific subtropical high, ENSO appears to influence the Aleutian low over the northwest Pacific. Thus, the moisture supply towards East Asia from the Pacific is determined by the strengthening/weakening of the subtropical high and the Aleutian low.

• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.247-255
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• 2016

As an attempt to determine the identity of the old trees of flowering cherries planted in the yard of the Catholic Archdiocese of Daegu, we conducted comparative phylogenetic analyses between wild and cultivated Prunus yedoensis Matsum. We generated the phylogeny (MP) and haplotype network (TCS) of 25 individuals, including wild P. yedoensis, from Jeju Island, cultivated P. ${\times}$yedoensis 'Somei-yoshino' from Korea and Japan, and P. spachiana f. ascendens (Makino) Kitam. from Jeju Island and Japan based on highly informative sequences of two cpDNA regions (rpl16 gene and trnS-trnG intergenic spacer). The wild and cultivated P. yedoensis were distinguished from each other in both the phylogeny and haplotype networks, and the old flowering cherry trees in Daegu had a cpDNA haplotype identical to that of the cultivated P. ${\times}$yedoensis 'Someiyoshino'. Compared to the cultivated P. ${\times}$yedoensis 'Somei-yoshino', wild P. yedoensis appears to have greater haplotype diversity, presumably originating from the genetic diversity of P. spachiana f. ascendens that functioned as a maternal parent in the hybrid origin of wild P. yedoensis. A future detailed study requires extensive sampling of P. spachiana f. ascendens from Japan and Korea to determine their precise phylogenetic relationships relative to wild and cultivated P. yedoensis. We concluded that the old flowering cherry trees planted in the yard of the Catholic Archdiocese of Daegu are highly likely to be of cultivated origin rather than wild types from Jeju Island, as previously speculated.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.415-422
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• 2013

This study was conducted to establish the optimum LED light source and quality for growth of Wasabia japonica seedlings in the LED chamber plant factory system. The light treatments were combined with four colors LED (red, blue, white, far-red), irradiation time ratio of the red and blue LED per minute(1:1, 2:1, 5:1, 10:1), and duty ratio of mixed light (100%, 99%, 97%). The growth response of W. japonica was the greatest in the R + B mixed light treatment, and seedlings grown in the red LED alone was higher than blue LED alone in the monochromic radiation treatments. In the R + B mixed LED, 1:1 ratio of R and B was the best for total biomass and tiller production. In mixed light treatments, the growth response of W. japonica was highest in the 100% duty ratio with R + B mixed light, while that was highest in the 97% duty ratio with R + B + W mixed light. Leaf area and dry weight were increased in the red light treatment alone, while specific leaf area was increased in the blue light alone. With the increasing red LED light ratio, leaf area and dry weight of W. japonica was significantly increased under the R + B mixed light treatment. In mixed light treatments, the leaf growth responses of W. japonica was highest in the 97% duty ratio with R+B mixed light, while that was highest in the 100% duty ratio with R + B + W mixed light. For cultivating W. japonica in a plant factory, treating red LED supplemented with a blue light or higher ratio of the red to blue LED was benefit to promote the growth of W. japonica.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.1
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• pp.25-31
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• 2008

Information on daily maximum air temperature is important in predicting the status of plants and insects, but the uneven and sparse distribution of weather stations prohibits timely access to the data in regions with complex topography. Since cumulative solar irradiance plays a critical role in determining daily maximum temperature on any sloping surfaces, derivation of a quantitative relationship between cumulative solar irradiance and the resultant daily maximum temperature is a prerequisite to development of such estimation models. Air temperatures at 8 sideslope locations with similar elevation and slope angle but aspect, circumventing a cone-shaped, grass-covered parasitic volcano (c.a., 570 m diameter for the bottom circle and 90m bottom-to-top height), were measured from June to December in 2007. Daily maximum temperatures from each location were compared with the average of 8 locations (assumed to be the temperature measured at a "horizontal reference" position). The temperature deviation at all locations increased with the day of year (or sun elevation) from summer solstice to winter solstice. Averaged over the entire period, the south facing location was warmer by $1^{\circ}C$ in daily maximum temperature than "horizontal reference" and the north facing location was cooler by $0.8^{\circ}C$ than the reference, resulting in the year round average south-north temperature difference of $1.8^{\circ}C$. In November, both south and north facing slopes showed the greatest deviation of $+2.0^{\circ}C$ and $-1.3^{\circ}C$, respectively in daily maximum temperature at monthly scale. On a daily scale, the greatest deviation was +3.8 and $2.7^{\circ}C$ at the south and north slope, respectively. The cumulative solar irradiance (on the slope for 4 hours from 11:00 to 15:00 TST) explained >60% of the variance in daily maximum temperature deviations among 8 locations, suggesting a feasibility of developing an estimation model for daily maximum temperature over complex topography at landscape scales.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.228-233
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• 2007

Pear psylla, Caccopsylla pyricola (Homoptera: Psyllidae), is a serious insect pest in pear orchards. C. pyricola overwinters as adults under rough bark scales of pear trees. When the weather warms up in the spring, the overwintered adults become active, climb up to the tree branches, and inhabit on fruit twigs to lay eggs. This study was conducted to develop a forecasting model for the onset of upward-movement of overwintered C. pyricola adults to control them by timely spraying of petroleum oil. The adult population densities were observed under rough barks (B) and on fruit twigs (T) of pear trees. Relative upward-movement rates (R) were calculated as T/(B+T). Low threshold temperatures for the activation of overwintered C. pyricola adults were selected arbitrarily from 5 to $9^{\circ}C$ at a $1^{\circ}C$ interval. Then, the days (D) when daily maximum air temperatures were above each low threshold temperature were counted from 1 February until to the dates with R $\geq$ 0.8. The same methods were applied for the prediction of the first observation of eggs. The variation of coefficients (CV) for the mean Des were lowest with the low threshold temperature of $6^{\circ}C$. At this selected threshold temperature, the upward movement of C. pyricola adults occurred with 12 D and they started laying eggs with 25 D. In the field validation, the model outputs with the $6^{\circ}C$ threshold temperature reasonably well explained the observed data in Suwon and Cheonan in 2002. Practical usages of the model were also discussed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.232-237
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• 2010

While global solar radiation is an essential input variable in crop models, the observation stations are relatively sparse compared with other meteorological elements. Instead of using measured solar radiation, the Angstrom-Prescott model estimates have been widely used. Monthly data for solar radiation and sunshine duration are a convenient basis for deriving Angstrom-Prescott coefficients (a, b), but it is uncertain whether daily solar radiation could be estimated with a sufficient accuracy by the monthly data - derived coefficients. We derived the Angstrom-Prescott coefficients from the 25 years observed global solar radiation and sunshine duration data at 18 locations across South Korea. In order to figure out any improvements in estimating daily solar radiation by replacing monthly data with daily data, the coefficients (a, b) for each month were derived separately from daily data and monthly data. Local coefficients for eight validation sites were extracted from the spatially interpolated maps of the coefficients and used to estimate daily solar radiation from September 2008 to August 2009 when, pyranometers were operated at the same sites for validation purpose. Comparison with the measured radiation showed a better performance of the daily data - derived coefficients in estimating daily global solar radiation than the monthly data - derived coefficients, showing 9.3% decrease in the root mean square error (RMSE).

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.1
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• pp.36-44
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• 2020

This study analyzed the Planting Prototype of Haengdan(杏壇)is the One of the traditional planting techniques and the value of natural monument plant and derived the value of the ginkgo tree in Sejong-ri as a natural monument. The results are as follows; First, ginkgo trees have high environmental adaptability, practicality and visual value. There were also many ginkgo trees that were deeply related to Confucian and Buddhist ideas. Ginkgo trees accounted for the largest portion of the number of old tree designated as natural monuments in recognition of their value. Second, after analyzing the historical and cultural values of ginkgo trees, ginkgo trees became the place of gardens and buildings by symbolizing Confucius(孔子)' Confucian ideas. In Buddhism, it was related to the creation of temples or the achievements of ancient monks. The people had a symbol of the prosperity of their offspring and the succession of the family. Third, in 1024 gongdobo, the grandson of Confucius, rebuilt the shrine, installed the platform in the central position and planted ginkgo trees. It originated from what he called "the "haengdan(杏壇)." The tree was then recorded as "heungheang(紅杏)" which was written by Wang Jae-jin's poetry during the Ming Dynasty. Thus it was misused as apricot tree. The cause of this is due to the same kanji reading. or it can be seen as influence on the taoism. But Korea has been sticking to the use of the first ginkgo trees. Forth, biologically, the Sejong-ri ginkgo tree is characterized by the composition of a pair of male trees. The landscape is contrasted with the twisted male tree and vertical female trees. In addition, in terms of authenticity and integrity, the relationship between Admiral Im, Nan-Su(林蘭秀) of the Goryeo Dynasty and the ginkgo tree is found in various literature.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.43-50
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• 2017

A xylan-degrading bacterium (strain WJ-1) was isolated from soil collected from Jeju Island, Republic of Korea. Strain WJ-1 was characterized as a gram-positive, aerobic, and spore-forming bacterium. The predominant fatty acid in this bacterium was anteiso-$C_{15:0}$ (42.99%). A similarity search based on 16S rRNA gene sequences suggested that the strain belonged to the genus Streptomyces. Further, strain WJ-1 shared the highest sequence similarity with the type strains Streptomyces spinoveruucosus NBRC 14228, S. minutiscleroticus NBRC 13000, and S. glaucescens NBRC 12774. Together, they formed a coherent cluster in a phylogenetic tree based on the neighbor-joining algorithm. The DNA G+C content of strain WJ-1 was 74.7 mol%. The level of DNA-DNA relatedness between strain WJ-1 and the closest related species S. glaucescens NBRC 12774 was 85.7%. DNA-DNA hybridization, 16S rRNA gene sequence similarity, and the phenotypic and chemotaxonomic characteristics suggest that strain WJ-1 constitutes a novel subspecies of S. glaucescens. Thus, the strain was designated as S. glaucescens subsp. WJ-1 (Korean Agricultural Culture Collection [KACC] accession number 92086). Additionally, strain WJ-1 secreted thermostable endo-type xylanases that converted xylan to xylooligosaccharides such as xylotriose and xylotetraose. The enzymes exhibited optimal activity at pH 7.0 and $55^{\circ}C$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.287-298
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• 2020

It is predicted that future climate warming will occur, and the subtropical climate zone currently confined to the south coast of Korea will gradually rise north. The shift of climate zone implies a change in area for cultivating crops. This study aimed to evaluate the current and future status of climate zones based on the high-resolution climate data of South Korea to prepare adaptation measures for cultivating crops under changing agricultural climate conditions. First, the climatic maps of South and North Korea were produced by using the high-resolution monthly maximum and minimum daily temperature and monthly cumulative precipitation produced during the past 30 years (1981-2010) covering South and North Korea. Then the climate zones of the Korean Peninsula were classified based on the Köppen climate classification. Second, the changes in climate zones were predicted by using the corrected monthly climate data of the Korean Peninsula (grid resolution 30-270m) based on the RCP8.5 scenario of the Korea Meteorological Administration. Köppen climate classification was applied based on the RCP8.5 scenario, the temperature and precipitation of the Korean Peninsula would continue to increase and the climate would become simpler. It was predicted that the temperate climate, appearing in the southern region of Korea, would be gradually expanded and the most of the Korean Peninsula, excluding some areas of Hamgkyeong and Pyeongan provinces in North Korea, would be classified as a temperate climate zone between 2071 and 2100. The subarctic climate would retreat to the north and the Korean Peninsula would become warmer and wetter in general.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.159-165
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• 2023

This study measured the ecological niche overlap between two deciduous oak species(Quercus acutissmia and Q. dentata) according to the change in growth responses after treating with the moisture and nutrient contents of the soil at four gradients, and interpreted the degree of competition between the two oak species by ordination method. In the moisture environment gradient, the ecological niche overlap of the two species was high in the photosynthesis-related leaf organs and low in plant architecture such as shoot length. In addition, in case of competition between two oaks, Q. dentata was remarkably dominant in soil moisture gradient, but Q. acutissimia slightly was slightly advantageous over Q. dentata in the soil nutrient gradient. These results show that even in a similar taxonomical group growing in a similar habitat, the response to the organ system of the plant varies depending on the type of environment factor, resulting in different competitive differences among plants.