• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.5
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• pp.25-35
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• 2023

The estuary reservoir is a major source of agricultural water in Korea; for effective and sustainable water resource management of the estuary reservoir, it is crucial to comprehensively consider various water resource factors, including water supply, flood, and pollutant management, and analyze future runoff changes in consideration of environmental changes such as climate change. The objective of this study is to estimate the impact of future climate change on the runoff characteristics of an estuary reservoir watershed. Climate data on future Shared Socioeconomic Pathway (SSP) scenarios were derived from two Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 6 (CMIP6). The Hydrological Simulation Program-Fortran (HSPF) was used to simulate past and future long-term runoff of the Ganwol estuary reservoir watershed. The findings showed that as the impact of climate change intensified, the average annual runoff in the future period was higher in the order of SSP5, SSP3, SSP1, and SSP2, and the ratio of runoff in July decreased while the ratio of runoff in October increased. Moreover, in terms of river flow regime, the SSP2 scenario was found to be the most advantageous and the SSP3 scenario was the most disadvantageous. The findings of this study can be used as basic data for developing sustainable water resource management plans and can be applied to estuary reservoir models to predict future environmental changes in estuary reservoirs.

• Korean Journal of Remote Sensing
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• v.11 no.3
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• pp.23-31
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• 1995

The International TOVS(TIROS Operational Vertical Sounders) Process Package(ITPP-VI), which has been installed at Korea Meteorological Administration(KMA), is only for a global usage to need a surface data to generate atmospheric soundings and total ozone amount. If the initial input process in the ITTP-VI is not modified, it takes climatic surface data for producing sounding data and total ozone amount in general. KMA is trying to improve the quality of TOVS total ozone amount using real-time synoptoc observation in various ways instead of climatological data because this retrieved data in the new scheme for total ozone presently used at the KMA may critically provide to analyze the long-term trend of ozone structure over the Korean peninsula. Two cases in this study show that TOVS retrieved total ozone amounts used by synoptic surface observations can delineate more detailed ozone structures rather than those used by climate surface data. The distribution of TOVS retrieved ozone amount fields with the synoptic surface analyzed data(TOVS-GPV) show more in detail relatively than those with the climate data(TOVS-CLIMAT) as expected. In addition, the collocated inter-comparisons of TOVS-GPV with TOVS-CLIMAT, TOMS observations and Dobsometer observations are performed statistically. TOVS-GPV fields with TOMS observations show smaller bias relatively than TOVS-CLIMAT and also reduce the differences.

• Korean Journal of Remote Sensing
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• v.32 no.3
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• pp.201-220
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• 2016

In this study, the net solar radiation fluxes at the surface are retrieved by updating an existing algorithm to be applicable for MODerate resolution Imaging Spectroradiometer (MODIS) observations, in which linear relationships between the solar radiation reflected from the top of atmosphere and the net surface solar radiation are employed. The results of this study have been evaluated through intercomparison with existing Clouds and the Earth's Radiant Energy System (CERES) data products and ground-based data from pyranometers at Gangneung-Wonju National University (GWNU) and the Southern Great Plains (SGP) of observatory of Atmospheric Radiation Measurement (ARM) site. Prior to the comparison of the surface radiation energy in relation to the energy balance of the earth, the radiation energy of the upper part of the atmosphere was compared. As a result, the coefficient of determination was over 0.9, showing considerable similarity, but the Root-Mean-Square-Deviation (RMSD) value was somewhat different, and the downward and net solar-radiation energy also showed similar results. The surface solar radiation data measured from pyranometers at Gangneung-Wonju National University (GWNU) and Atmospheric Radiation Measurement (ARM) observatory are used to validate the solar radiation data produced in this study. When compared to the GWNU, The results of this study show smaller RMSD values than CERES data, showing slightly better agreements with the surface data. On the other hand, when compared with the data from ARM SGP observatory, the results of this study bear slightly larger RMSD values than those for CERES. The downward and net solar radiation estimated by the algorithm of this study at a high spatial resolution are expected to be very useful in the near future after refinements on the identified problems, especially for those area without ground measurements of solar radiation.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.471-479
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• 2011

Evapotranspiration (ET) including evaporation from a land surface and transpiration from photosynthesis of vegetation is a hydrological factor that has an important role in water cycle. However, there is a limitation to understand it due to heterogeneity of land cover and vegetation. In this study, Mapping EvapoTRanspiration with Internalized Calibration (METRIC) model, one of the energy balance models, and MODerate resolution Imaging Spectroradiometer (MODIS) satellite based well-known Penman-Monteith algorithm were compared. Two ET maps were categorized and compared by land cover classification. The results represented overall applicability of the two models with the highest correlation coefficients in needleleaf and broadleaf forests. This study will be useful to estimate remote sensing based ET maps with high resolution and to figure out spatio-temporal variability and seasonal changes.

• Atmosphere
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• v.15 no.2
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• pp.91-99
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• 2005

This study compares the summer monsoon circulations during a heavy rainfall period over the Korean peninsular from 11 to 18 July 2004, simulated by three widely used regional models; WRF, MM5, and RSM. An identical model setup is carried out for all the experiments, except for the physical option differences in the RSM. The three models with a nominal resolution of about 50 km over Korea are nested by NCEP-DOE reanalysis data. Another RSM experiment with the same cumulus parameterization scheme as in the WRF and MM5 is designed to investigate the importance of the representation of subgrid-scale parameterized convection in reproducing monsoonal circulations in East Asia. All thee models are found to be capable of reproducing the general distribution of monsoonal precipitation, extending northeastward from south China across the Korean peninsula, to northern Japan. The results from the WRF and MM5 are similar in terms of accumulated precipitation, but a slightly better performance in the WRF than in the MM5. The RSM improves the bias for precipitation as compared to those from the WRF and MM5, but the pattern correlation is degraded due to overestimation of precipitation in northern China. In the comparison of simulated synoptic scale features, the RSM is found to reproduce the large-scale features well compared to the results from the MM5 and WRF. On the other hand, the simulated precipitation from the RSM with the convection scheme used in the MM5 and WRF is closer to that from the WRF and MM5 simulations, indicating the significant dependency of simulated precipitation in East Asia on the cumulus parameterization scheme.

• Atmosphere
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• v.28 no.1
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• pp.25-35
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• 2018

This study presents future potential sea level change over the seas surrounding Korea using Climate Model Intercomparison Project Phase 5 9 model ensemble result from Representative Concentration Pathways (RCPs), downloaded from icdc.zmaw.de. At the end of 21st century, regional sea level changes are projected to rise 37.8, 48.1, 47.7, 65.0 cm under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenario, respectively with the large uncertainty from about 40 to 60 cm. The results exhibit similar tendency with the global mean sea level rise (SLR) with small differences less than about 3 cm. For the East Sea, the Yellow Sea, and the southern sea of Korea, projected SLR in the Yellow Sea is smaller and SLR in the southern sea is larger than the other coastal seas. Differences among the seas are small within the range of 4 cm. Meanwhile, Commonwealth Scientific and Industrial Research Organization (CSIRO) data in 23 years shows that the mean rate of sea level changes around the Yellow Sea is high relative to the other coastal seas. For sea level change, contribution of ice and ocean related components are important, at local scale, Glacial Isostatic Adujstment also needs to be considered.

• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.308-313
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• 1997

TDS (Thermal Lkso~ption Spectroscopy)system, for diagnosis of CRT manufacturing process, was designed and constructed. Outgassings and themla1 desorptions from the part or materials of CRT can be measured and analysed with this system at various temperatures. The system is consisted of 3 pirrts. vacuum chamher and pumping system with variable conductance, sample heating stages & their controller, and outgassing measurement devices, like as ion gauge or quadrupole mass spectrometer. The ultimate pressure of the system was under $1\times10^{-7}$ Pa. With the variable conductance system, the effective pumping speed of the chamber could he controlled from sub 11s to 100 11s. The effective pumping speed values were determined by dynamic flow measurement principle. The temperatures and ramp rate of sample were controlled by tungsten heater and PID controller up to $600^{\circ}C$ within t $\pm 1^{\circ}C$$difference to setting value. Ion gauge & QMS were calibrated for quantitative measurements. Some examples of TDS measurement data ;ind application on the CRT process analysis were shown.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.5
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• pp.375-384
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• 2001

Optical remote sensing techniques are particularly advantageous over the conventional fixed point methods because with these methods large-area monitoring can be possible and sample preparation difficulties are avoidable. Instruments based on the differential optical absorption spectroscopy (DOAS) technique are widely used for monitoring air pollutants in urban areas in recent years. In this study, $O_3$, SO$_2$, NO$_2$, and VOCs (benzene, toluene, xylene, and styrene) are measured continuously at Sihwa industrial area using a DOAS from February to November. 1999. Intercomparison between the DOAS method and the conventional methods (filed point samplers for $O_3$, NO$_2$, and SO$_2$, and adsorbent sampling methods and gas chromatography for VOCs) are performed simultaneously at the same site. The time series of the DOAS data and that of fixed point method show good match at the view point of the tendency, but the absolute concentration values of these two methods differ quite a lot from each other; correlation coefficients shows 0.78 for $O_3$and 0.97 for SO$_2$. However, the results of VOCs measurements are not quite satisfactory ; the spectral interference with $O_2$and $O_3$appears to be the major cause of the errors for VOCs .

• Journal of Korean Society of Rural Planning
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• v.19 no.4
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• pp.125-135
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• 2013

Analysis and evaluation of uncertainty is adopting the advanced methodology among the methods for greenhouse gas emission assessment that was defined in GPS2000 (Good practice guideline 2000) and GPG-LULUCF (GPG Land Use, Land-Use Change and Forestry). In 2006 IPCC guideline, two approaches are suggested to explain the uncertainty for each section with a national net emission and a prediction value on uncertainty as follows; 1) Spread sheet calculation based on the error propagation algorithm that was simplified with some assumptions, and 2) Monte carlo simulation that can be utilized in general purposes. There are few researches on the agricultural field including greenhouse gas emission that is generated from livestock and cultivation lands due to lack of information for statistic data, emission coefficient, and complicated emission formula. The main objective of this study is to suggest an evaluation method for the uncertainty of greenhouse gas emission in agricultural field by means of intercomparison of the prediction value on uncertainties which were estimated by spread sheet calculation and monte carlo simulation. A statistic analysis for probability density function for uncertainty of emission rate was carried out by targeting livestock intestinal fermentation, excrements treatment, and direct/indirect emission from agricultural lands and rice cultivation. It was suggested to minimize uncertainty by means of extraction of emission coefficient according to each targeting section.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.186-191
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• 2007

The objective of this research was to assess the reliability of data and to improve nuclear analytical techniques concerning the Domestic Radioactivity Intercomparison program for environmental radioactivity monitoring of Jeju from 1998 to 2006. Gross beta for filter papers and water samples was determined, and gamma nuclides for natural and artificial nuclides in soil and water samples were analyzed. The gross beta activity of all samples except for the water samples of 1998 and 1999 showed a good agreement within the confidence intervals. In gamma nuclides, $^{40}K$ and $^{137}Cs$ of soil samples and most nuclides in the water samples, with the exception of several nuclides, were evaluated to be reliable. Based on these results, it is considered that a reliable method for the analysis and monitoring of environmental radioactivity were established, which may play an important role in case of emergency radiation accident.