• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.1-5
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• 2013

In this paper, we present a conversion algorithm of the oblique ionogram obtained from Jeju and Icheon to the equivalent vertical ionogram of the path mid-point, based on some equivalence theorems between the vertical sounding and the oblique sounding for the ionosphere. And in order to verify the conversion algorithm under the condition of no vertical ionosonde at the mid-point on the test path, the equivalent vertical ionograms are compared to the real vertical ionograms measured adjacently in space-time. The comparison results show that the conversion algorithm performs well for the short-path oblique ionogram and the equivalent vertical ionograms could be applied to get the electron density profiles at the mid-point.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.22 no.1
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• pp.1.2-5
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• 1994

Ionospheric sounding experiments have been conducted at RRL (Radio Research Laboratory), Ministry of Communications, using Digisonde 256 since its installation in 1990. Routine observations of the vertical sounding are carried out 48 times (or 39 times) a day, at every 24 hour. In addition, we also made oblique sounding experiments to obtain the real time data of Maximum Usable Frequency (MUF) and detect the anomalous HF propagation, as a part of the joint study between RRL and CRL (Communications Research Laboratory) of Japan. The two stations involved in the study were Anyang (RRL, Korea) and Kokubunji (CRL, Japan). The ionosondes used in both stations were Digisonde 256, developed by ULCAR (University of Lowell, Center for Atmospheric Research), U. S. A. , and the synchronization of time was accomplished with the help of GPS receiver. During most part of the experiments RRL transmitted non-modulated pulses, and CRL received them. The experiment was scheduled from October 25 through October 29, 1993. However, the ionosphere was not developed well enough to conduct the experiment with pre-set operation parameters. The experiment became successful (from 0500 UT to 0800 UT, October 29) only after the operation parameters had been changed, and the continuous ionograms were obtained by CRL at 0718 UT and 0733 UT in October 29, 1993. We believe this type of experiment will ensure the qualitative enhancement of solar-terrestrial physics research and a routine observation of the oblique ionospheric sounding. In this report, we present the results of the fore-mentioned oblique sounding as well as the vertical sounding results obtained by Digisonde 256 at Anyang station of RRL.

• Geophysics and Geophysical Exploration
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• v.10 no.3
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• pp.211-218
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• 2007

In this study, vertical electrical sounding (VES) data and ordinary kriging are used to identify the alluvial depth of each area that Korea Resources Corporation (KORES) conducted groundwater survey at Miryang area in Gyeongsangnam-do and Pocheon area in Gyeonggi-do from 2003 to 2004. To verify the applicability of VES data to ordianry kriging, regression analysis of VES data versus drillhole data is conducted. Comparing the alluvial depth distributions using ordinary kriging with existing drillhole data, the result shows that the depth distributions are reasonably depicted along with the topography and the basin. So, the ordinary kriging of VES data is useful to identify the alluvial depth distributions.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.345-355
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• 1996

The effectiveness of various electrode configurations in horizontal mappings and 1-D inversions of vertical sounding data for delineating 2-D structures was studied. Apparent resistivity values of three point, dipole-dipole, Wenner, and Schlumberger mappings were simulated for such structures as vertical dyke, tabular prism, buried vertical fault, ramp and complex structure by finite difference method (FDM) and they were compared with each other. Also 2-D cross sections for three structures obtained by interpolation of 1-D inverted sounding data in terms of three layers were compared for Schlumberger and Wenner arrays. On these cross sections, horizontal and vertical resistivity interfaces of the 2-D structures are revealed relatively clearly. Apparent resistivity curves of Schlumberger mapping show vertical resistivity discontinuities very well. On the whole, Schlumberger array is superior to the other arrays in electric sounding as well as mapping. This study clearly indicates that interpretations of 2-D structures based on 1-D inversion are possible.

• Geophysics and Geophysical Exploration
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• v.15 no.2
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• pp.51-56
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• 2012

One of the most critical and essential procedures in the interpretation of gravity and magnetic data is to separate the anomaly due to the specific geologic structure from the summation of effects from a broad variety of geologic sources, especially those of different depths. Separation of the residual anomaly from the regional field is the most simple case of the vertical separation. If the anomaly due to a layer of specific depth can be separated or the depth of the separated layer can be quantitatively determined, it may deserve the separation-sounding. We suggest a wavelength filter whose cutoff frequency is determined by log-power spectrum analysis, as a separation-sounding filter. We applied this filter both to synthetic and real gravity data acquired at Heunghae area, and compared the results with those of Jacobsen's upward continuation filter. These showed that the proposed separation-sounding filter could be a useful tool for interpretation of the vertical geologic structure by stripping the gravity effects of geologic sources down to the desired depth.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.35-43
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• 1992

Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are "A" and "B" at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.al dispersion model.

• Economic and Environmental Geology
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• v.20 no.1
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• pp.77-82
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• 1987

An analysis is made for the relative effectiveness in detecting a subsurface thin layer by four electromagnetic depth sounding systems; horizontal coplanar loops, perpendicular loops, vertical coplanar loops and vertical coaxial loops. The moduli and phases of mutual coupling ratios over a three-layered earth for the four systems are evaluated rapidly by the related convolution technique. Root mean square differences between the responses from the three-layered and the homogeneous earths are used to compare the relative effectiveness of the systems quantitatively. Comparing the all systems, it is found that the perpendicular loop system appears to be the most superior to the other systems.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.154-162
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• 2013

Vertical electrical sounding and 2D electrical resistivity survey were applied for evaluating the characteristics of alluvial layers at a groundwater artificial recharge site. The fine particles in alluvial layer, main target layer of groundwater artificial recharge, may cause clogging phenomena. In this case, electrical resistivity method is an effective technique to verify the spatial distribution of low-resistivity layers, such as saturated silts and clays. On the other hand, much attention should be paid to interpret the resistivity data in unconsolidated layers, because thick clayey overburden sometimes produces a masking effect on underlying interbedded resistive sands and gravels. Considering these points, we designed 35 points arranged in a grid form for vertical electrical sounding and 10 lines for 2D electrical resistivity survey, and concentrated our effort on enhancing the vertical and horizontal resolution of resistivity images. According to the results, 15 meters thick layers consisting of sands and gravels are located in 30 meters below ground. And the spatial distribution of silts and clays are mapped, which may cause clogging. Consequently, this approach can contribute to design and determine the location and depth of injection and observation wells for groundwater artificial recharge.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.201-203
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• 2003

Two MODIS instruments on board the Terra and Aqua Satellites are operational for global remote sensing of the land, ocean and atmosphere. Atmospheric sounding data with a high spatial resolution from MODIS will provide a wealth of useful information. The vertical air temperature and moisture data were retrieved using the MODIS data, and compared with the radiosonde data obtained in the Korean Peninsula. The correlation coefficient are 0.99 and 0.89 for air temperature and moisture cases, respectively. Air temperature data were relatively good agreement, but the moisture data from MODIS were underestimated.

• Journal of Astronomy and Space Sciences
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• v.9 no.2
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• pp.193-202
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• 1992

The fist sounding rocket in Korea, KSR-420S has been under the development at Korea Aerospace Research Institute (KARI), and is expected to be launched in 1993 to measure the vertical ozone profile over the Korean Peninsula. The KSR-420S is expected to provide the fist in situ measurement of ozone concentrations over the Korean Peninsula. An optical ozone detector has been developed at Korea Research Institute of Standards and Science (KRISS), and its calibration has been completed recently. In this paper, measurement principles of the ozone detector in KSR-420S, its calibration data, ozone measurement procedure and data reduction algorithm are presented with sample calculations.