• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.693-706
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• 2020

For ten meteorological observatories running an automated synoptic observing system (ASOS), we classified the observation environments into five classes based on the World Meteorological Organization (WMO) classification guidelines. Obstacles (such as topography and buildings) and land-cover types were the main factors in evaluating the observation environments for the sunshine duration, air-temperature, and surface wind. We used the digital maps of topography, buildings, and land-cover types. The observation environment of the sunshine duration was most affected by the surrounding buildings when the solar altitude angle was low around the sunrise and sunset. The air-temperature observation environment was determined based on not only the solar altitude angle but the distance between the heat/water source and ASOS. There was no water source around the ASOSs considered in this study. Heat sources located near some ASOSs were not large enough to affect the observation environment. We evaluated the surface wind observation environment based on the roughness length around the ASOS and the distance between surrounding buildings and the ASOS. Most ASOSs lay at a higher altitude than the surroundings and the roughness lengths around the ASOSs were small enough to satisfy the condition for the best level.

• Journal of Astronomy and Space Sciences
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• v.17 no.1
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• pp.87-98
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• 2000

We examine the relative contributions of the electric field and ionospheric conductance to the auroral electrojets. For this purpose we used magnetometer data obtained from the International Magnetospheric Study (IMS) meridian chains of observatories for March 17, 18, and 19, 1978. Based on the study by Allen & Kroehl (1975), we redefine the AU and AL indices by utilizing the magnetic disturbance data obtained from the AE stations located within limited magnetic local time (MLT) sectors; i.e., $1500\leq MLT\leq1800$ and$0000\leq MLT\leq0300$, respectively. The current densities of the eastward and westward electrojets are calculated based on the AU and AL indices thus defined. Under the assumption that the Hall conductance at the dusk sector is mainly caused by the solar EUV radiation, we estimate the electric field contributin to the AU index. Assuming further that electric field distributins at dawn and dusk sectors are comparable, it is also possible to estimate the contribution of the Hall conductance associated at the dusk sector is mainly caused by the solar EUV radiation, we estimate the electric field contribution to the AU index. Assuming further that electric field distributions at dawn and dusk sectors are comparable, it is also possible to estimate the contribution of the Hall conductance associated with auroral particle precipitation to the AL index. From this study it is noted that the electric fields and Hall conductances thus estimated show significant correlations with the AU and AL indices, respectively, suggesting that the AU and AL indices are closely associated with the directly driven and loading-unloading processes of substorms.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.2
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• pp.70-78
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• 2002

The landscape disign of Gamcheon wholesale fish Market was designed around a turnkey base to promote the economy of Busan Metropolitan City, to establish a fishery marketing center and to modernize existing facilities. The objectives of the project were to promote the mood of an old market, while preserving its functions and efficiency as a market, to design outdoor spaces with natural resources and amenities in balance, and to create attractive tourist spots in connection with the wide area development plan. The project was oriented, fast, to enhance the functions of the market. For this purpose, a multi-dimensional space layout was designed in consideration of functions as a wholesale market. The safety of pedestrians was secured by separating lathes for vehicles and for pedestrians. Tree planting with various functions such as sheltering, wind breaking and guiding was planned. Secondly, nature-friendly and human-friendly landscaping design was attempted. For this, the beautiful natural resources of Amnam Park were utilized, and green spaces such as green bridges linking buildings in the wholesale market, and rooftop gardens were to be arranged. In addition, environment-friendly facilities such as roads paved with natural materials(i.e. gravel, shells) and program parking lots were to be planned. Thirdly, landscape design was considered to create attractive tourist spots. For example, a fish farm was created as a theme street for pedestrians and various water-friendly spaces such as pedestrian ramps, observatories and seaside streets were to be secured. The main contents are as follows. First, a green bridge to Ahnnam Park was introduced for a tour source and flower garden, an event plan and viewing deck open to the sea were planned on the bridge's axis. Secondly, for the effective land use plan concerning open space and convenience to visitors, a promenade was planned, which is connected with the theme plaza and small plazas by environmental sculptures in front of the market hall and at the gate. As well, an observatory and a roof garden help create three dimensional multi leveled space, with a good view of the natural landscape of the sea, sky and park Thirdly, landscape materials, such as trees and those for facilities, strengthened for protection against the seawind and salt damage were selected. The commercial market area was intended to be transformed a traditional functional area of efficiency and economy into an attractive marine leisure area where both tourists and neighbors can make use of it.

• Journal of Astronomy and Space Sciences
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• v.24 no.3
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• pp.249-260
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• 2007

The crustal deformation due to Ocean Tide Loading (OTL) in the Korean peninsula reaches up to ${\sim}3cm$ in the vertical direction. Considering that the achievable positioning accuracy of current state-of-the-art space geodesy technologies is at the several millimeter level, the centimeter-level OTL effect should be precisely modelled and corrected for. This study begins with comparison of ocean tide models and validation of OTL-prediction softwares. Different ocean tide models caused about ${\sim}6mm$ RMS differences in the vertical deformation in the Kyung-gi Bay area. When we analyzed the OTL displacements in the Seoul, Ulsan, and Seogwipo areas where three VLBI observatories are planned to be installed, the maximum displacement of ${\sim}3.5cm$ was predicted in the Seogwipo area and ${\sim}2cm$ in the Seoul and Ulsan areas. When the OTL corrections were not applied in the GPS data processing, the OTL effect propagates into the Zenith Wet Delay (ZWD) estimates, and the scale factor between ZWD differences and OTL displacements was 3.72.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.259-274
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• 2014

On Aug 18, 2013, Sakurajima volcano in Japan erupted on a relatively large-scale. Geostationary Ocean Color Imager (GOCI) had used to detect volcanic ash in the surrounding area on the next day of this eruption. The geomagnetic variation has been analyzed using geomagnetic data from Cheongyang observatory in Korea and several geomagnetic observatories in Japan. First, we reconstruct geomagnetic data by principal component analysis and conduct semblance analysis by wavelet transform. Secondly, we minimize the error of solar effect by using wavelet based semblance filtering with Kp index. As a result of this study, we could confirm that the geomagnetic variation usually occur at the moment of Sakurajima volcano eruption. However, we cannot rule out the possibilities that it could have been impacted by other factors besides volcanic eruption in other variation's cases. This research is an exceptional study to analyze geomagnetic variation related with abroad volcanic eruption uncommonly in Korea. Moreover, we expect that it can help to develop further study of geomagnetic variation involved in earthquake and volcanic eruption.

• Journal of the Korean Geotechnical Society
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• v.30 no.6
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• pp.51-59
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• 2014

Shallow landslides and debris flows are a common form of soil slope instability in South Korea. These events may be generally initiated as a result of intense rainfall or lengthening rainfall duration because of the effects of climate change. This paper presents the evaluation of rainfall-induced natural soil slope stability and reinforced soil slope instability under vertical load (railway or highway load) throughout South Korea based on quantitative analysis obtained from 58 sites rainfall observatories for 38 years. The slope stability was performed for infinite and geogrid-reinforced soil slopes by taking an average of maximum rainfall every ten years from 1973 to 2010. Seepage analysis is carried out on unsaturated soil slope using the maximum rainfall at each site, and then the factor of safety was calculated by coupled analysis using saturated and unsaturated strength parameters. The contour map of South Korea shows four stages in 10-year-time for the degree of landslide hazard. The safety factor map based on long term observational data will help prevent rainfall-induced soil slope instability for appropriate design of geotechnical structures regarding disaster protection.

• Journal of the Korean earth science society
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• v.28 no.1
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• pp.123-135
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• 2007

Five episodes of the large-scale transport of air pollutants in East Asia and its inflow into the Korean Peninsula have been analyzed through satellite and ground observations. These episodes include regionally polluted continental airmass, which is created by the pollutants produced in the cities and the industrial regions in China, to land on or pass through the Korean Peninsula by way of the Yellow Sea. The analysis of the NOAA satellite observation data made it possible to create images by combining 3 channels of visible and infrared ray ranges and also to identify the distribution and the transport of the air pollution mass over the Yellow Sea. The ground observation data of the air pollutants gathered in Chongwon were found highly valuable in verifying the information in comparison with ones from the satellite. Especially, regarding the episodes of large-scale transport of the air pollutants, the difference of concentration between $PM_{10}\;and\;PM_{2.5}$ was found small with the increase of $PM_{2.5}$ value. The concentration of $PM_{10}$ in the episode of yellows and, however, was found much higher than that of $PM_{2.5}$. In the episode of 27 January 2006, the inflow of the regionally polluted continental air mass into the central and southwestern region of the Korean Peninsula was observed sequentially in the various ground observatories as well as by the satellite. The north-northwest airflow dissipated the clouds over from Mt. Halla in Jeju Island up to far downwind, reduced air pollution, and created von $K\acute{a}rm\acute{a}n$ vortex.

• Journal of Environmental Science International
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• v.26 no.5
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• pp.573-584
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• 2017

In order to simulate a typhoon precisely, the satellite observation data has been assimilated using WRF (Weather Research and Forecasting model) three-Dimensional Variational (3DVAR) data assimilation system. The observation data used in 3DVAR was GPS Radio Occultation (GPS-RO) data which is loaded on Low-Earth Orbit (LEO) satellite. The refractivity of Earth is deduced by temperature, pressure, and water vapor. GPS-RO data can be obtained with this refractivity when the satellite passes the limb position with respect to its original orbit. In this paper, two typhoon cases were simulated to examine the characteristics of data assimilation. One had been occurred in the Western Pacific from 16 to 25 October, 2015, and the other had affected Korean Peninsula from 22 to 29 August, 2012. In the simulation results, the typhoon track between background (BGR) and assimilation (3DV) run were significantly different when the track appeared to be rapidly change. The surface wind speed showed large difference for the long forecasting time because the GPS-RO data contained much information in the upper level, and it took a time to impact on the surface wind. Along with the modified typhoon track, the differences in the horizontal distribution of accumulated rain rate was remarkable with the range of -600~500 mm. During 7 days, we estimated the characteristics between daily assimilated simulation (3DV) and initial time assimilation (3DV_7). Because 3DV_7 demonstrated the accurate track of typhoon and its meteorological variables, the differences in two experiments have found to be insignificant. Using observed rain rate data at 79 surface observatories, the statistical analysis has been carried on for the evaluation of quantitative improvement. Although all experiments showed underestimated rain amount because of low model resolution (27 km), the reduced Mean Bias and Root-Mean-Square Error were found to be 2.92 mm and 4.53 mm, respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.202-214
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• 2014

We introduce status and prospect of increasingly utilizing, unmanned, global ocean observing systems, and the global network to integrate, coordinate, and manage the systems. Platforms of the ocean observing system are diversified in order to resolve/monitor the variability occurring at multiple scales in both three-dimensional space and time. Here purpose, development history, and current status of the systems in two kinds - mobile (surface drifter, subsurface float, underwater glider) and fixed platforms (surface and subsurface moorings, bottom mounts), are examined and the increased future uses to produce synergies are envisioned. Simultaneous use of various mobile and fixed platforms is suggested to more effectively design the observing system, with an example of the NSF-funded OOI (Ocean Observations Initiative) program. Efforts are suggested 1) to fill the data gap existing in the deep sea and the Southern Ocean, and toward 2) new global network for oceanic boundary currents, 3) new technologies for existing and new sensors including biogeochemical, acoustic, and optical sensors, 3) data standardization, and 4) sensor calibration and data quality control.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.4
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• pp.57-65
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• 2015

This study investigates characteristics of time series spatial distribution on climate factors in Andong Dam basin by estimating precise spatio-temporal distribution of hydro-meteorological information. A spatio-temporal distribution by estimating Semi-Variogram based on spatial autocorrelation was examined using the data from ASOS and 7 hydro-meteorological observatories in Andong Dam basin of upper Nakdonggang River, which were installed and observed by NIMR(National Institute of Meterological Research). Also, temperature and humidity as climate variables were analyzed and it was recognized that there is a variability in watershed area by time and months. Regardless of season, an equal spatial distribution of temperature at 14 o'clock and humidity at 10 o'clock was identified, and nonequal distribution was noticed for both variables at 18 o'clock. From monthly spatial analysis, the most unequal distribution of temperature was seen in January, and the most equal distribution was detected in September. The most unequal distribution of humidity was identified in May, and the most equal distribution was seen in January. Unlike in forest, seasonal spatial distribution characteristics were less apparent;but temperature and humidity had respective characteristics in hydro-meteorology.