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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean earth science society
Journal Basic Information
Journal DOI :
The Korean Earth Science Society
Editor in Chief :
Volume & Issues
Volume 34, Issue 7 - Dec 2013
Volume 34, Issue 6 - Oct 2013
Volume 34, Issue 5 - Sep 2013
Volume 34, Issue 4 - Aug 2013
Volume 34, Issue 3 - Jun 2013
Volume 34, Issue 2 - Apr 2013
Volume 34, Issue 1 - Feb 2013
Selecting the target year
Characteristics of Chaff Echoes Observed by X-band Dual Polarization Radar
Seo, Eun-Kyoung ; Park, Sora ; Nam, Kyung-Yeub ; Heo, Sol-Ip ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 1~12
DOI : 10.5467/JKESS.2013.34.1.1
To effectively remove chaff echoes, which are often misidentified as precipitation echoes on weather radars, this study examines the relationship between the radar reflectivity and each of dual polarimetric parameters. The dual polarimetric parameters are collected only for the echo areas identified as chaff echoes on the NIMR X-band dual polarization radar. Overall, the polarimetric parameters (i.e., reflectivity, differential reflectivity, cross correlation coefficient, standard deviation of differential reflectivity and specific differential phase) for chaff echoes have a wider range of values than those for precipitation echoes and the chaff filaments tend to be horizontally oriented to radar beams. There appears to be a considerable overlap in the cross correlation coefficient range of chaff and precipitation echoes since some precipitation echoes have cross correlation coefficient lower than 0.8. Therefore, although the cross correlation coefficient is known to be a good variable in identifying and separating chaff echoes from precipitation echoes, it is suggested that additional care should be taken when using the cross correlation coefficient solely in removing chaff echoes.
The Adjustment of Radar Precipitation Estimation Based on the Kriging Method
Kim, Kwang-Ho ; Kim, Min-seong ; Lee, Gyu-Won ; Kang, Dong-Hwan ; Kwon, Byung-Hyuk ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 13~27
DOI : 10.5467/JKESS.2013.34.1.13
Quantitative precipitation estimation (QPE) is one of the most important elements in meteorological and hydrological applications. In this study, we adjusted the QPE from an S-band weather radar based on co-kriging method using the geostatistical structure function of error distribution of radar rainrate. In order to estimate the accurate quantitative precipitation, the error of radar rainrate which is a primary variable of co-kriging was determined by the difference of rain rates from rain gauge and radar. Also, the gauge rainfield, a secondary variable of co-kriging is derived from the ordinary kriging based on raingauge network. The error distribution of radar rain rate was produced by co-kriging with the derived theoretical variogram determined by experimental variogram. The error of radar rain rate was then applied to the radar estimated precipitation field. Locally heavy rainfall case during 6-7 July 2009 is chosen to verify this study. Correlation between adjusted one-hour radar rainfall accumulation and rain gauge rainfall accumulation improved from 0.55 to 0.84 when compared to prior adjustment of radar error with the adjustment of root mean square error from 7.45 to 3.93 mm.
Oxygen Isotopic Ratios for Ultramafic Xenoliths from the Korean Peninsula
Lee, Jeong-A ; Kim, Kyuhan ; Lee, Jong-Ik ; Choo, Mikyung ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 28~40
DOI : 10.5467/JKESS.2013.34.1.28
This study examined the geochemical characteristics, equilibrium temperature and pressure conditions, and oxygen isotopic ratios of mantle xenoliths from the various geological sites of the Korean peninsula. The results are as follows: (1) The ultramafic xenoliths from the Korean peninsula mainly consist of typical high magnesium olivine (MgO : 49.12-50.95 wt.%, Mg value: 90.1-92.2), corresponding to worldwide Cenozoic ultramafic xenoliths in chemical compositions. (2) The pressure-temperature conditions of ultramafic xenoliths in the Korean peninsula are from 854 to
and 4.6 to 24.4 kbar. (3) The oxygen isotopic ratios (
) for olivines in ultramafic xenoliths range from 5.06‰ to 5.51‰, which are relatively uniform oxygen isotopic values and overlapped by the values of N-MORB and upper mantle peridotite (
‰). However, olivines of the ultramafic xenoliths from the Baegdusan and Chejudo have a relatively wide
values ranging from 5.07 to 5.51‰ and 5.07 to 5.45‰, respectively. Based on the results, this study suggests that the high
signature of the Baegdusan xenoliths give a hint that ~5% of the oxygen in typical EM2 sources originally derived from recycled sediments.
Distribution of Flood Sediment Deposits using the Seafloor Image by Side Scan Sonar near the Northern Coast of Gungchon-ri, East Sea
Lee, Cheol-Ku ; Jung, Seom-Kyu ; Kim, Seong-Ryul ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 41~50
DOI : 10.5467/JKESS.2013.34.1.41
To analyze the distribution pattern of flood sediment deposits near the mouth of Chucheoncheon (river), side scan sonar images and seafloor sediment properties were investigated in the offshore area within about 50 m deep in water. Based on the analysis result of the sonar images, the seafloor of the study area is divided into three areas of basement, sandy-mud, and dispersed flood sediment. The colors of sonar images in each area are represented by dark black, light grey, and greyish black, respectively. The sediment composition in the grey black area shows 33.73% of gravel, 62.88% of sand, 3.37% of silt, and 0.02% of clay. On the other hand, the composition of the light grey area is 10.31% of sand, 56.42% of silt, and 33.27% of clay. Especially the sediment of the grey black area contains the considerable amount of burned plant fragments in black color, which could distinctly be differentiated from those in the offshore. The distribution pattern of the flood sediment deposits suggests that the land-originated detrital sediments seem to be transported from the Chucheon river into offshore along the shore rather than transversely. In conclusion, the longshore current of the study area is probably dominant to affect the spatial distribution of bottom features.
Sensitivity of Numerical Solutions to Time Step in a Nonlinear Atmospheric Model
Lee, Hyunho ; Baik, Jong-Jin ; Han, Ji-Young ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 51~58
DOI : 10.5467/JKESS.2013.34.1.51
An appropriate determination of time step is one of the important problems in atmospheric modeling. In this study, we investigate the sensitivity of numerical solutions to time step in a nonlinear atmospheric model. For this purpose, a simple nondimensional dynamical model is employed, and numerical experiments are performed with various time steps and nonlinearity factors. Results show that numerical solutions are not sensitive to time step when the nonlinearity factor is not influentially large and truncation error is negligible. On the other hand, when the nonlinearity factor is large (i.e., in a highly nonlinear regime), numerical solutions are found to be sensitive to time step. In this situation, smaller time step increases the intensity of the spatial filter, which makes small-scale phenomena weaken. This conflicts with the fact that smaller time step generally results in more accurate numerical solutions owing to reduced truncation error. This conflict is inevitable because the spatial filter is necessary to stabilize the numerical solutions of the nonlinear model.
Source Characteristics of the Recent Earthquakes for Seven Years in the Southwestern Region of the Korean Peninsula
Jung, Mi Kyeong ; Kyung, Jai Bok ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 59~68
DOI : 10.5467/JKESS.2013.34.1.59
Focal mechanism solutions in the southwestern region of the Korean Peninsula (
) were obtained from the analysis of the recent 22 earthquakes (
) occurred from January, 2005 to March, 2011. The spatial differences between the epicenters recalculated by this study and those by KMA (Korea Meteorological Administration) and KIGAM (Korea Institute of Geoscience and Mineral Resources) are less than
, indicating a small deviation. However, they become a little bit larger in the coastal area due to a biased arrangement of seismic stations. Redetermined depths of hypocenters show a difference less than 12.7 km by comparison with the depth data announced by KIGAM. Most epicenters in inland area are located closely to the lineaments. Fault plane solutions were obtained from the analysis of P and SH wave polarities, and SH/P amplitude ratios. They show strike-slip faulting or strike-slip faulting with reverse components dominantly. The P-axes trends are mainly ENE-WSW or E-W directions. The direction of fault plane and auxiliary plane with 'NNE-SSW and WNW-ESE' or 'NE-SW and NW-SE' are dominant and almost parallel to the general trends of lineaments in the study area.
Compression of Terrain Data using Integer Wavelet Transform (IWT) and Application on Gravity Terrain Correction
Chung, Hojoon ; Lee, Heuisoon ; Oh, Seokhoon ; Park, Gyesoon ; Rim, Hyoungrea ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 69~80
DOI : 10.5467/JKESS.2013.34.1.69
Terrain data is one of important basic data in various areas of Earth science. Recently, finer DEM data is available, which necessary to develop a method that deals with such huge data efficiently. This study was conducted on the lossless compression of DEM data and efficient partial reconstruction of terrain information from compressed data. In this study, we compressed the wavelet coefficients of DEM, obtained from integer wavelet transform (IWT) by entropy encoding. CDF (Cohen-Daubechies-Feauveau) 3.5 wavelet showed the best compression ratio of about 45.4% and the optimum decomposition level was 3. Results also showed that a small region of terrain could be restored from the inverse wavelet transform with a part of the wavelet coefficients that are related to such region instead of whole reconstruction. We discussed the potential applications of the terrain data compression for precise gravity terrain correction.
A Communication Structure of Science Gifted Students Based on the Social Network Analysis
Chung, Duk-Ho ; Yoo, Dae Young ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 81~92
DOI : 10.5467/JKESS.2013.34.1.81
The purpose of this study was to investigate the communication structures that science gifted students used in small group activities, and to examine the relationship between communication styles and their achievement level. Eight small groups,5 members in each, participated in small group activities, in which they discussed how to calculate the average density of the earth. The communication structures and the achievement level presented in the group activities were analyzed using Pajek, Ucinet 6.0. As a result, we classified the communication styles of science gifted students into monopolistic type and co-ownership type according to the degree of dispersion of the interaction. We also classified it into
type based on the density and network centralization of interaction. The achievement levels of gifted students in their group work were affected by the density of interaction and the network centralization in small group activities, not by the dispersion of interaction among the members of the groups. Therefore, we recommend that teachers make the communication relevant to solving problem when they utilize a small group activity in science teaching.
Two Middle School Science Teachers' Experiences of Teaching Science in the Republic of Korea: A Phenomenological Analysis
Nam, Younkyeong ; Jang, Myoung-Duk ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 93~101
DOI : 10.5467/JKESS.2013.34.1.93
This study investigated how the unique educational contexts in the Republic of Korea (RK) impacted two science teachers' teaching practices in a public middle school and what the science teaching experience means to them. In particular, we explored how the middle school science teachers decide pedagogical approaches to use in their teaching based on classroom climate, students' attitude toward learning science, school curriculum and classroom culture. Using a phenomenological research approach, we analyzed classroom observation data and interview data to interpret the teachers' science teaching experience. Results of the study showed that the teachers' practice was dominantly affected by two external factors. First, the teachers' teaching practice was affected by the amount of science content knowledge they need to cover within a given class time. Second, the teachers' teaching practice was affected by students' attitudes toward science learning and their science preparedness in private tutoring centers. Implications of the study results are discussed in the paper.
Diagnosis of Northeast Asian Summer Precipitation using the Western North Pacific Subtropical High Index
Kwon, MinHo ;
Journal of the Korean earth science society, volume 34, issue 1, 2013, Pages 102~106
DOI : 10.5467/JKESS.2013.34.1.102
The intensity of the East Asian summer monsoon has a negative correlation with that of the western North Pacific summer monsoon. Based on the relationship, we suggest the potential predictability of Northeast Asian summer precipitation by using the relationship. The western North Pacific subtropical high (WNPSH) properly represents the intensity of the western North Pacific summer monsoon. It also dominates climate anomalies in the western North Pacific-East Asian region in summertime. The estimates of the Northeast Asian summer rainfall anomalies using WNPSH variability have a greater benefit than those using the western North Pacific monsoon index.