• Atmosphere
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• v.17 no.4
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• pp.435-453
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• 2007

KEOP (Korea Enhanced Observing Period)-2004 intensive summer observation was carried out from 20 June to 5 July 2004 over the Southwestern part of the Korean peninsula. In this study, the effects of KEOP-2004 intensive observation data on the simulation of precipitation system are investigated using KLAPS (Korea Local Analysis and Prediction System) and PSU/NCAR MM5. Three precipitation cases during the intensive observation are selected for detailed analysis. In addition to the control experiments using the traditional data for its initial and boundary conditions, two sensitivity experiments using KEOP data with and without Jindo radar are performed. Although it is hard to find a clear and consistent improvement in the verification score (threat score), it is found that the KEOP data play a role in improving the position and intensity of the simulated precipitation system. The experiments started at 00 and 12 UTC show more positive effect than those of 06 and 18 UTC. The effect of Jindo radar is dependent on the case. It plays a significant role in the heavy rain cases related to a mesoscale low over Changma front and the landing of a Typhoon. KEOP data produce more strong difference in the 06/18 UTC experiments than in 00/12 UTC, but give more positive effects in 00/12 UTC experiments. One of the possible explanations for this is that : KEOP data could properly correct the atmosphere around them when there are certain amounts of data, while gives excessive effect to the atmospheric field when there are few data. CRA analysis supports this reasoning. According to the CRA (Contiguous Rain Area) analysis, KEOP data in 00/12 UTC experiments improve only the surrounding area, resulting in essentially same precipitation system so the effects remain only in each convective cell rather than the system itself. On the other hand, KEOP data modify the precipitation system itself in 06/18 UTC experiments. Therefore the effects become amplified with time integration.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.57-68
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• 1995

Precipitation samples were collected by a wet-only automatic acid precipitation sampler at Kangwha island on the western coast in Korea, through January until December 1992. pH, electric conductivity and the concentrations of major water-soluble ion components such as N $H_{4}$$^{+}$, $Ca^{2+}$, $K^{+}$, $Mg^{2+}$, N $a^{+}$, N $O_{3}$$^{[-10]}$ , S $O_{4}$$^{2-}$ and C $l^{[-10]}$ were measured. From the result of checking the validity for assesment of pollution level of precipitation samples by pH using correlation analysis between pH and major components, and t-test of chemical composition between acid rain and non-acid rain, pH proved to be not satisfactory for its pillution level. A more comprehensive method is therefore required. In order to estimate the monthly analytical result of chemical composition of precipitation samples comprehensively, a cluster analysis was used among the various multivariate statistical analysis. As a result of making a cluster analysis for separating the monthly precipitation samples into homogeneous patterns by setting the concentrations of nine major water-soluble ion components as a variable, three homogeneous patterns were obtained. The first pattern was a group of months having average ion concentrations, the second a guoup of months having low ion concentration, and the third a group of months having high ion concentrations. Thus, it was indicated that the pollution level of precipitation was higher on February and lower on May, June, August and September than the other months. As a result, this analysis method could be estimated the chemical coposition of precipitation regionally as well as monthly.monthly.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.21-26
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• 2003

Develop and need design application of carbon sex design concept that consider plasticity in elastic design concept until now. To Place that is representative construction of hull in this research rain deflection pattern analysis technique and grandeur increment method such as general load type increment law and displacement type increment law and Newton-Raphson method increment body law to use jointly compare. Specialty. through analysis by initial deflection pattern. examined closely carbon set conduct of place by initial deflection pattern. Applied thin plate structure which receive compressive load used ANSYS that analysis method is mediocrity finite element analysis program to save complicated conduct that effect that conduct after initial buckling and conduct after secondary buckling get in the whole construction is very big and such and grandeur increment law presumes complicated rain fan shape conduct in bifurcation point specially.

• Atmosphere
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• v.19 no.1
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• pp.37-51
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• 2009

Kinematic characteristics of a heavy rainfall event occurred in Changma front are analyzed using synoptic weather charts, satellite imagery and NCEP(National Centers for Environmental Prediction) / NCAR(National Centers for Atmospheric Research) reanalysis data. The heavy rainfall is accompanied with mesoscale rain clouds developing over the Southwest region of Korea during the period from 0300 LST to 2100 LST 25 June 2006. The surface cyclone in the Changma front is generated and developed rapidly when it meets following vertical conditions: The maximum value of relative vorticity is appeared at 700 hPa and is extended gradually near the surface. It is thought that the vertical structure of relative vorticity is closely related with the descent of strong wind zone exceeding $10ms^{-1}$. The jet core at 200 hPa is shifted southward and extended downward and the low-level jet stream associated with upper-level jet stream appeared at 850 hPa. Kinematic features of heavy rainfall system at cyclone-generating point are as follows: In the generating stage of cyclone, the relative vorticity below 850 hPa increased and the convergence below 850 hPa and the divergence at 400 hPa are intensified by southward movement of jet core at 200 hPa. The heavy rainfall system seems to locate to the south of the exit region of upper-level jet streak; In the developing stage of cyclone, the relative vorticity below 850 hPa and the convergence near surface are further strengthened and upward vertical velocity between 850 hPa and 200 hPa is increased.

• Journal of architectural history
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• v.14 no.2 s.42
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• pp.143-157
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• 2005

This study aims to analyze functions and characteristics of 'Cha-il(遮日)' which was used at ritual events(宮中儀禮行事) in the Joseon dynasty, Joseon dynasty had many ritual events related with O-Rae(五禮). Cha-il was almost used at important ritual events, especially at the congratulatory events. The congratulatory events(宮中宴享) are the representative events were held with many temporary install facilities(假設施設) in a palace. Cha-il was a kind of Korean traditional membrane structures. Cha-il was set up for cutting off interior space from sunlight and rain. In general, Cha-il was Consisted of Cha-il-jang(遮日帳:woven fabric), Cha-il-jook(遮日竹:bamboo column), some ropes, and fixing wares. In the congratulatory events, three types of Cha-il. were set up. Baek-mok-Dae-Cha-il(白木大遮日)was made of cotton cloth. Yu-Dun-Cha-Il(油芚遮日) was made of oiled paper or oiled cotton cloth. Man-Joen-Cha-Il(滿箭遮日) consisted of wooden structure. Baek-mok-Dae-Cha-il(白木大遮日)was set up on the most important area of stage for protecting from sunlight. Yu-Dun-Cha-Il was set up on less important area of stage for protecting from sunlight and rain. Man-Joen-Cha-Il was set up below Baek-mok-Dae-Cha-il for supporting and draining raindrops off. The results of this study were as follows; Functions of Cha-il were to protect ritually space from sunlight and rain, and to extend ritually space, and to reconstruct ritually space. Cha-il was the peculiar temporary install facility which differed from other countries.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.607-613
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• 2015

In order to design M/W(microwave) short backhaul above 10 GHz to meet the increase in mobile traffic demand, the rain attenuation as well as the atmospheric conditions such as Earth bulge and Fresnel zone should be considered. In this paper, the path lengths have been estimated theoretically in various frequency bands using the Korean standard rain rate, and an example of path profile has been analyzed in urban area utilizing spectrum management intelligence system (SMIS). These derived minimum path lengths in various frequency bands are compared to the foreign them, and then will be proposed to improve the Korean minimum path length unitized to 10 km. This paper will provide useful information for microwave engineers in designing a M/W access link, and be utilized to make an efficient usage of high frequency bands for the short mobile broadband backhaul.

• Journal of Korea Water Resources Association
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• v.47 no.2
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• pp.207-221
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• 2014

Recently, due to global warming, climate change has affected short time concentrated local rain and unexpected heavy rain which is increasingly causing life and property damage. Therefore, this paper studies the characteristic of localized heavy rain and flash flood in Nakdong basin study area by applying Data Mining method to predict flood and constructing water level predicting model. For the verification neural network from Data Mining method and hydraulic flood routing was used for flood from July 1989 to September 1999 in Nakdong point and Iseon point was used to compare flood level change between observed water level and SAM (Slope Area Method). In this research, the study area was divided into three cases in which each point's flood discharge, water level was considered to construct the model for hydraulic flood routing and neural network based on artificial intelligence which can be made from simple input data used for comparison analysis and comparison evaluation according to actual water level and from the model.

• Analytical Science and Technology
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• v.16 no.6
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• pp.466-474
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• 2003

This paper describes the concentrations of total dissolved iron (tFe) and $Fe^{2+}$ in rainwater and snow, the relationship of Fe species with other metals and ions in bulk rainwater, and the $Fe^{2+}$ generation mechanism in aqueous samples in rainwater of time series collection. Volume weight mean concentrations of tFe and $Fe^{2+}$ were 3.22 and $1.25{\mu}gL^{-1}$ in bulk rainwater, and 50.1 and $43.5{\mu}gL^{-1}$ in snow, respectively. $Fe^{2+}$ was significant fraction to the tFe, accounted for 3.25-93.4% of the tFe in rainwater and 87% in snow. We also investigated temporal variations of tFe, $Fe^{2+}$, other metals and ions in rainwater of time series collection during rain event. Although the concentration range of tFe was different from those of other species, a decreasing trend of tFe from the beginning of the rain event was similar with other species. However, though $Fe^{2+}$ did not show such a decreasing trend, $Fe^{2+}$/tFe was in good correlation with solar radiation. From the results of multiple linear regression analysis and thermodynamic calculations (Mineql+), $Fe^{2+}$ in our samples may be generated from photochemical reduction of $Fe^{3+}$ species (such as $Fe(OH)^{2+}$,$Fe(OH)^{2+}$ and Fe-oxalate) at daytime.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.23-28
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• 1996

In order to investigate the chemical components of acid precipitation at Samchok City in Korea, the rainwater was collected according to 3mm rainfall from september 1994 to december 1994. pH, electric conductivity were measured and ionic components were analyzed by Ion chromatography. As the analytical results, the average value were 6.27 for pH, 53.16 S/cm for E.C., the average concentration were 393.42 eq/1 for C $l^{[-10]}$ , 18.41 eq/1 for N $O_{3}$$^{[-10]}$ , 91.44 eq/1 for S $O_{4}$$^{2-}$, 335.92 eq/1 for N $a^{+}$, 65.66 eq/1 for N $H_{4}$$^{+}$, 18.22 eq/1 for $K^{+}$, 120.49 eq/1 for $Mg^{2+}$ and 147.04 eq/1 for $Ca^{2+}$. pH value correlated negatively with rainfall amount and the component of C $l^{[-10]}$ and N $a^{+}$ were transported to urban air by the seasalt. It showed that S $O_{4}$$^{2-}$ and N $O_{3}$$^{[-10]}$ had influence on acidity of precipitation, 73% and 27%, respectively, in this area. Ion Concentration of N $O_{3}$$^{[-10]}$ was higher than S $O_{4}$$^{2-}$ in the early rain, S $O_{4}$$^{2-}$ was higher than N $O_{3}$$^{[-10]}$ in the succeeding rain by multi-regration analysis. the percentages of removal by percipitation were higher in N $O_{3}$$^{[-10]}$ than in S $O_{4}$$^{2-}$./TEX> 2-/.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.335-346
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• 2006

Among various input data to hydrologic models, rainfall measurements arguably have the most critical influence on the performance of hydrologic model. Traditionally, hydrologic models have relied on point gauge measurements to provide the area-averaged rainfall information. However, rainfall estimates from gauges become inadequate due to their poor representation of areal rainfall, especially in situations with sparse gauge network. Alternatively, radar that covers much larger areas has become an attractive instrument for providing area- averaged precipitation information. Despite of the limitation of the QPE(Quantitative Precipitation Estimation) using radar, we can get the better information of spatial variability of rainfall fields. Also, rain-gauges give us the better quantitative information of rainfall field. Therefore, in this study, we developed improved methodologies tu estimate rainfall fields using an ordinary cokriging technique which optimally merges radar reflectivity data into rain-gauges data.