• Journal of Ecology and Environment
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• 제42권4호
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• pp.265-271
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• 2018

Background: Temperature-driven variation in pollinator assemblage and activity are important information, especially at high altitudes, where rising temperature trends exceed global levels. Temporal patterns of pollinators in a flowering season can be used as a proxy to predict the changes of high-altitude plants' mutualistic relationships. We observed a spring temperature change in one population of a high-altitude endemic species, Megaleranthis saniculifolia on Mt. Sobaeksan, and related it to pollinator assemblage and activity changes. Methods: This study was conducted at two sites, each facing different slopes (NE and NW), for two times in the spring of 2013 (early-flowering, April 27-28, vs. mid-flowering, May 7-8, 2013). We confirmed that the two sites were comparable in snowmelt regime, composition of flowering plants, and flower density, which could affect pollinator assemblage and activity. Pollinator assemblage and activity were investigated at three quadrats ($1m^2$ with 5-m distance) for each site, covering a total of 840 min observation for each site. We analyzed correlations between the temperature and visitation frequency. Results: Twelve pollinator species belonging to four orders were observed for M. saniculifolia at both sites during early- and mid-flowering times. Diptera (five species) and hymenopteran species (four species) were the most abundant pollinators. Pollinator richness increased at both sites toward the mid-flowering time [early vs. mid = 7 (NE) and 3 (NW) vs. 9 (NE) and 5 (NW)]. Compared to the early-flowering time, visitation frequency showed a fourfold increase in the mid-flowering time. With the progression of spring, major pollinators changed from flies to bees. Upon using data pooled over both sites and flowering times, hourly visitation frequency was strongly positively correlated with hourly mean air temperature. Conclusions: The spring temperature change over a relatively brief flowering period of M. saniculifolia at high altitudes can alter pollinator assemblages through pollinator dominance and visitation frequency changes. Thus, this study emphasizes information on intra- and inter-annual variations in the mutualistic relationship between pollinators and M. saniculifolia to further assess the warming impacts on M. saniculifolia's reproductive fitness.

• Journal of the Korean Wood Science and Technology
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• 제18권4호
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• pp.65-78
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• 1990

For the purpose of Improving the sounding boards for the conventional GAYAKUM, I was making approximately 202 specimens of radial board, 371 specimens of tangential board by cutting along the grain and the part of stem and 31 specimens of the disjointed traditional GAYAKUM made in Paulownia coreana. And it was conducted to measure specific gravity, dynamic Young's modulus, internal friction, resonant frequency, velosity of sound and width of annual ring by the method of the frexural vibration in a free-free bar in the audio frequency range. And it confirmed the juvenile wood by measuring wood fiber length of specimens. It was also conducted to investigate dynamic properties and moisture absorption by various heat-treatment and to test dynamic Young's modulus and internal friction for the disjointed conventional GAYAKUM. The results obtained were summarized as follow: 1. The Juvenile wood is located within about 7 annual rings from the pith in Paulownia coreana. 2. As increased with the specific gravity, the dynamic Young's modulus had more and more increased, but the internal friction had slightly decreased. 3. I think that radial board would be good for sounding board wood. because radial board is higher than tangential board in dynamic Young's mudulus and internal friction is lower than tangential board. 4. The value of mean dynamic Young's modulus on the conventional GAYAKUM, radial board and tangential board of 604 samples is $0.4283\pm0.037(\times10^{11}dyne/cm^2)$, $0.4316\pm(\times10^{11}dyne/cm^2)$ and $0.4234\pm0.112(\times10^{11}dyne/cm^2)$ respectively. The value of the radial board showed little higher than that of conventional GAYAKUM, but It had a similar tendency between conventional GAYAKUM and tangential board. 5. The annual ring width by four aspect is more narrow in north and west than that of others. 6. The values of specific gravity and dynamic Young's modulus in the mature wood showed higher than those of juvenile wood. 7. As the grain angle in the butt wood more increased to bark from pith, the dynamic Young's modulus were low. Then it was not good for sounding board. 8. It appeared that the heat-treatment for sounding board wood had a more effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature. 9. As increased with the temperature, the rate of moisture absorption of heat-treatment wood had decreased. In conclusion, I thought that the sounding board wood for GAYAKUM would had the most effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature using the radial board of mature wood.

• Korean Journal of Remote Sensing
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• 제32권5호
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• pp.423-434
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• 2016

Surface emissivity and its background values according to each sensor are mandatorily necessary for Mid-Wavelength Infrared (MWIR) remote sensing to retrieve surface temperature and temporal variation. This study presents the methods and results of Land Surface Emissivity (LSE) of the MWIR according to land cover over the Korean Peninsula. The MWIR emissivity was estimated by applying the Temperature Independent Spectral Indices (TISI) method to the Visible Infrared Imaging Radiometer Suite (VIIRS) band 4 Day/Night images ($3.74{\mu}m$ in center wavelength). The obtained values were classified according to land-cover types, and the obtained emissivity was then compared with those calculated from a standard Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) spectral library. The annual means of MWIR emissivity of Deciduous Broadleaf Forest (0.958) and Mixed Forest (0.935) are higher than those of Croplands (0.925) and Natural Vegetation Mosaics (0.935) by about 2-3%. The annual mean of Urban area is the lowest (0.914) with an annual variation of about 2% which is by larger than those (1%) of other land-covers. The TISI and VIIRS based emissivity is slightly lower than the ASTER spectral library by about 2-3% supposedly due to various reasons such as lack of land cover homogeneity. The results will be used to understand the MWIR emissivity properties of the Korean Peninsula and to examine the seasonal and other environmental changes using MWIR images.

• Journal of People, Plants, and Environment
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• 제24권5호
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• pp.519-527
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• 2021

Background and objective: This study was conducted to establish a Plant Hardiness Zone (PHZ) map, investigate the effect of global warming on changes in PHZ, and elucidate the difference in the distribution of evergreen trees between the central and southern region within hardiness Zone 7b in Korea. Methods: Mean annual extreme minimum temperature (EMT) and related temperature fluctuation data for 40 years (1981 to 2020) in each of the meteorological observation points were extracted from the Open MET Data Portal of the Korea Meteorological Administration. Using EMT data from 60 meteorological observation points, PHZs were classified according to temperature range in the USDA Plant Hardiness Zone Map. Changes in PHZs for each decade related to the effects of global warming were analyzed. Temperature fluctuation before and after the day of EMT were analyzed for 4 areas of Seoul, Suwon, Suncheon, and Jinju falling under Zone 7b. For statistical analysis, descriptive statistics and ANOVA were performed using the IBM SPSS 22 Statistics software package. Results: Plant hardiness zones in Korea ranged from 6a to 9b. Over four decades, changes to warmer PHZ occurred in 10 areas, especially in colder ones. Based on the analysis of daily temperature fluctuation, the duration of sub-zero temperatures was at least 2 days in Seoul and Suwon, while daily maximum temperatures were above zero in Suncheon and Jinju before and after EMT day. Conclusion: It was found that the duration of sub-zero temperatures in a given area is an important factor affecting the distribution of evergreen trees in PHZ 7b.

• Journal of Ecology and Environment
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• 제29권1호
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• pp.23-27
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• 2006

This study was conducted to evaluate forest carbon cycling and soil $CO_2$ efflux rates in a 42-year-old pine (Pinus densiflora) stand located in Hamyang-gun, Korea. Aboveground and soil organic carbon storage, litterfall, litter decomposition, and soil $CO_2$ efflux rates were measured for one year. Estimated aboveground biomass carbon storage and increment in this stand were $3,250gC/m^2\;and\;156gC\;m^{-2}yr^{-1}$, respectively. Soil organic carbon storage at the depth of 30 cm was $10,260gC/m^2$ Mean organic carbon inputs by needle and total litterfall were $176gC\;m^{-2}yr^{-1}\;and\;235gC\;m^{-2}yr^{-1}$, respectively. Litter decomposition rates were faster in nne roots less than 2 mm diameter size ($<220\;g\;kg^{-1}yr^{-1}$) than in needle litter ($<120\;g\;kg^{-1}yr^{-1}$). Annual mean and total soil respiration rates were $0.37g\;CO_2m^{-2}h^{-1}$ and $2,732g\;CO_2m^{-2}yr^{-1}$ during the study period. A strong positive relationship existed between soil $CO_2$ efflux and soil temperature (r=0.8149), while soil $CO_2$ efflux responded negatively to soil pH (r=-0.3582).

• Journal of Environmental Science International
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• 제29권3호
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• pp.257-272
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• 2020

This study investigates the temporal and spatial variations of marine meterological elements (air temperature (Temp), Sea Surface Temperature (SST), and Significant Wave Height (SWH)) in seven coastal waters of South Korea, using hourly data observed at marine meteorological buoys (10 sites), Automatic Weather System on lighthouse (lighthouse AWS) (9 sites), and AWS (20 sites) during 2013-2017. We also compared the characteristics of Temp, SST, and air-sea temperature difference (Temp-SST) between sea fog and non-sea-fog events. In general, annual mean values of Temp and SST in most of the coastal waters were highest (especially in the southern part of Jeju Island) in 2016, due to heat waves, and lowest (especially in the middle of the West Sea) in 2013 or 2014. The SWH did not vary significantly by year. Wind patterns varied according to coastal waters, but their yearly variations for each coastal water were similar. The maximum monthly/seasonal mean values of Temp and SST occurred in summer (especially in August), and the minimum values in winter (January for Temp and February for SST). Monthly/seasonal mean SWH was highest in winter (especially in December) and lowest in summer (June), while the monthly/seasonal variations in wind speed over most of the coastal waters (except for the southern part of Jeju Island) were similar to those of SWH. In addition, sea fog during spring and summer was likely to be in the form of advection fog, possibly because of the high Temp and low SST (especially clear SST cooling in the eastern part of South Sea in summer), while autumn sea fog varied between different coastal waters (either advection fog or steam fog). The SST (and Temp-SST) during sea fog events in all coastal waters was lower (and more variable) than during non-sea-fog events, and was up to -5.7℃ for SST (up to 5.8℃ for Temp-SST).

• Journal of the korean society of oceanography
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• 제38권3호
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• pp.111-121
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• 2003

The seasonal succession of zooplankton communities in the coastal area off Incheon, Kyeonggi Bay, was investigated with the samples collected at intervals of 10 to 15 days from January 1999 to December 2000. Total abundance of zooplankton communities showed remarkable seasonal variations, ranged from 1,100 to $120,400{\;}indiv./\textrm{m}^3$, and annual mean abundance was $22,000{\;}indiv./\textrm{m}^3$. There were several times of the total abundance during a year, and the timing ofhigh abundances were about the same in 1999 and 2000. During the study period except summer, the abundance of dinoflagellate Noctiluca scintillans and copepod Acartia hongi contributed to the most part of total zooplankton. Whereas, during summer, smaller copepod Oithona davisae and Paracalanus crassirostris were dominant species. Zooplankton communities in the coastal waters off Incheon showed typical characteristics of coastal-estuarine communities, which were dominated by a few species, and abrupt seasonal variations in abundance. We suggest that the seasonal succession and abundance variations of zooplankton communities were caused by the seasonal variations in water temperature and by the seasonally varying phytoplankton biomass in the study area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• 제36권1호
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• pp.33-39
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• 2018

As the retrieval accuracy of PWV estimates from GPS measurements is proportional to the accuracy of water vapor WMT, the WMT model is a significant formulation in the conversion of PWV from the GPS ZWD. The purpose of this study is to develop a MWMT model for the retrieval of highly accurate GPS PWV using the radiosonde measurements from six upper-air observing stations in the region of Korea. The values of 1-hr PWV estimated at four GPS stations during one year are used to evaluate the validity of the MWMT model. It is compared to the PWV obtained from radiosonde data that are located in the vicinity of GPS stations. Intercomparison of radiosonde PWVs and GPS PWVs derived using different WMT models is performed to assess the quality of our MWMT model for Korea. The result in this study indicates that the MWMT model is an effective model to retrieve the enhanced accurate GPS PWV, compared to other GPS PWV derived by Korean annual or global WMT models.

• Journal of Korean Society for Atmospheric Environment
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• 제16권1호
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• pp.37-47
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• 2000

The Urban thermal environment is influenced and modified in many ways. One modification is brought by the anthropogenic heat generation emitted from the combustion processes and the use of energy such as industrial, domestic and traffic procedure. The anthropogenic heat generation affect an the increase of urban temperature, the well-known urban heat islands. The study on the urban thermal environment needs a great deal of the statistic data about the inner-structure of urban, the contribution of different constructions and the traffic amount on urban thermal environment in finite region. In order to overtake a quantitative analysis of effect of the anthropogenic heat, a distribution map of the urban anthropogenic heat was made using hte data of the energy consumption used at the several constructions and traffic amount of vehicles in Pusan Metropolitan. Annual mean heat flux over the 4$\textrm{km}^2$ urbanized area in Pusan is 41.5W/$m^2$, ranging from 31.4W/$m^2$ in summertime to 59.5W/$m^2$ in wintertime and maximum diurnal anthropogenic heat generation is corresponding to 10% of irradiance during summertime.

• Journal of Environmental Science International
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• 제9권2호
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• pp.109-114
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• 2000

The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.