• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.126-138
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• 1996

The characteristics of rapid development of the low pressure system over the East Sea from 06 to 08 Nov., 1995 has been analyzed in detail by the synoptic numerical products and satellite observations. The Low system was initially triggered the development of the baroclinic leaf cloud over the border of the northern part of Korea and China and moved eastward and then developed explosively com-ma or lambda type cloud system over the East Sea. To forecast well the general development and movement of the coastal winter cyclone over the East Sea popularly in a numerical simulation by several scientists, the large baroclinicity, continuous support of water vapor, and sequential cold outbreak over the warm sea surface have been more commonly concerned about. The cyclone which the central surface pressure was dropped 40hPa within 24 hours has often accompanied strong wind and heavy snow- or rain-fall in the winter season. In all successive observations with 12-hourly satellite imagery and analyzed meteorological variables in this period, the centers of the sea-level pressure and 500hPa geopotential height associated with this cyclone were typically illustrated by moving farther eastward using GMS combined enhanced IR images. The maxi-mum wind sustained by this system with the intensity and central pressure of tropical storm was about 60 knots with the center pressure drop of 44hPa/day similar to the North American cyclonic bomb and Atlantic storm.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.695-700
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• 2014

This paper analyzed the peak stage of typhoons by using 10 years(2002~2011) data. The main purpose of this research is to provide the characteristic and tendency of peak stage of typhoons for navigators of ship. The research results show that typhoons of maximum wind speed 20~29m/ s and 40~49m/s account for 25% and 24% of whole typhoon, respectively. Ultra Typhoon of maximum wind speed 50m/ s and over accounts for 24% of whole typhoon. Peak stage mean arrival time from tropical depression and tropical storm are 3.6 days and 2.1 days, respectively. Duration time of peak stage is within 2 days and mean duration time of peak stage is 31hours. Latitudes and longitudes that mainly appears peak stage are at $15^{\circ}{\sim}25^{\circ}N$ and $120^{\circ}{\sim}140^{\circ}E$. This dangerous sea area has the oceanic environmental characteristic that Taiwan and Philippines are locate west side and a vast the North Pacific occupy east side. Navigators of ship in this dangerous sea area keep strict watch. Ultra Typhoons occur most frequently in September. Peak stage of Ultra Typhoon also appears at $15^{\circ}{\sim}25^{\circ}N$ and $120^{\circ}{\sim}140^{\circ}E$.

• The Korean Journal of Petroleum Geology
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• v.9 no.1_2 s.10
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• pp.1-15
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• 2001

Hierarchically controlled sequence stratigraphic analysis shows that the Lower Ordovician mixed carbonatesiliciclastic Mungok Formation, Korea consists of three depositional sequences: T1, T2, and T3 in ascending order. Sequence boundaries are generally marked by abrupt transition from coarse-grained shallow-water carbonates to finegrained deeper-water carbonates mixed with fine-grained siliciclastics, and show indication of subaerial exposure such as karstification. Within this sequence stratigraphic framework, facies characteristics indicate that the Mungok sequences were mostly deposited on a subtidal ramp without slope break. The Mungok ramp had been under the influence of frequent tropical storm activity during deposition. The difference in lithology of tempestites seems to have been controlled by the nature of substrates and by proximality. High-frequency cycles consist of upward-shallowing facies successions. Cycles of shallow-water and basinal deposits are not well represented, probably due to cycle amalgamation. Cycle stacking patterns do not show a consistent thickness change that is usually associated with a large-scale sea-level change probably because of unfilled accommodation space.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.69-79
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• 2017

In this study, we developed real-time urban stream discharge forecasting model using short-term rainfall forecasts data simulated by a regional climate model (RCM). The National Centers for Environmental Prediction (NCEP) Climate Forecasting System (CFS) data was used as a boundary condition for the RCM, namely the Global/Regional Integrated Model System(GRIMs)-Regional Model Program (RMP). In addition, we make ensemble (ESB) forecast with different lead time from 1-day to 3-day and its accuracy was validated through temporal correlation coefficient (TCC). The simulated rainfall is compared to observed data, which are automatic weather stations (AWS) data and Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA 3B43; 3 hourly rainfall with $0.25^{\circ}{\times}0.25^{\circ}$ resolution) data over midland of Korea in July 26-29, 2011. Moreover, we evaluated urban rainfall-runoff relationship using Storm Water Management Model (SWMM). Several statistical measures (e.g., percent error of peak, precent error of volume, and time of peak) are used to validate the rainfall-runoff model's performance. The correlation coefficient (CC) and the Nash-Sutcliffe efficiency (NSE) are evaluated. The result shows that the high correlation was lead time (LT) 33-hour, LT 27-hour, and ESB forecasts, and the NSE shows positive values in LT 33-hour, and ESB forecasts. Through this study, it can be expected to utilizing the real-time urban flood alert using short-term weather forecast.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.17-24
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• 2018

The HEC-HMS model was applied to identify the rainfall-runoff processes for the Anseongchun basin, where the lower part of the stream has been damaged severely by tropical storms in the past. Modeling processes include incorporating with the SCS-CN model for loss, Clark's UH model for transformation, exponential recession model for baseflow, and Muskingum model for channel routing. The parameters were calibrated through an optimization technique using a trial and error method. Sensitivity analysis after calibration was performed to understand the effects of parameters, such as the time of concentration, storage coefficient, and base flow related constants. Two storm water events were simulated by the model and compared with the corresponding observations. Good accuracy in predicting the runoff volume, peak flow, and the time to peak flow was achieved using the selected methods. The results of this study can be used as a useful tool for decision makers to determine a master plan for regional flood control management.

• Wind and Structures
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• v.10 no.3
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• pp.287-300
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• 2007

Wind action is a factor of fundamental importance in the structural design of light or slender constructions. Codes for structural design usually assume that the incident mean wind velocity is parallel to the ground, which constitutes a valid simplification for frequent winds caused by meteorological phenomena such as Extratropical Storms (EPS) or Tropical Storms. Wind effects due to other phenomena, such as thunderstorms, and its combination with EPS winds in so-called squall lines, are simply neglected. In this paper a model that describes the three-dimensional wind velocity field originated from a downburst in a thunderstorm (TS) is proposed. The model is based on a semi empirical representation of an axially-symmetrical flow line pattern that describes a stationary field, modulated by a function that accounts for the evolution of the wind velocity with time. The model allows the generation of a spatially and temporally variable velocity field, which also includes a fluctuating component of the velocity. All parameters employed in the model are related to meteorological variables, which are susceptible of statistical assessment. A background wind is also considered, in order to account for the translational velocity of the thunderstorm, normally due to local wind conditions. When the translation of the TS is caused by an EPS, a squall line is produced, causing the highest wind velocities associated with TS events. The resulting vertical velocity profiles were also studied and compared with existing models, such as the profiles proposed by Vicroy, et al. (1992) and Wood and Kwok (1998). The present model predicts horizontal velocity profiles that depend on the distance to the storm center, effect not considered by previous models, although the various proposals are globally compatible. The model can be applied in any region of interest, once the relevant meteorological variables are known, to simulate the excitation due to TS winds in the design of transmission lines, long-span crossings, cable-stayed bridges, towers or similar structures.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.248-266
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• 2020

Purpose: The purpose of this study is to create a checklist for each type of disaster and to suggest a method for establishing an appropriate response system and making accurate and rapid decision-making. Method: In order to derive checklist factors, previous case analyses (Tropical Storm Rusa (2002), Typhoon Maemi (2003), and Typhoon Chaba (2016) were conducted for typhoon disaster. Grouping was conducted to derive checklist factors by analyzing general status (climate and weather) information and characteristics by case. Result: The case study was divided into national level and county level. In terms of national unit, eight forecasts were included: weather forecast, typhoon landing status, typhoon intensity, typhoon radius, central pressure, heavy rain conditions, movement speed, and route. Local governments should reflect regional characteristics, focusing on the presence or absence of similar typhoons (paths) in the past, typhoon landing time, regional characteristics, population density, prior disaster recovery, recent disaster occurrence history, secondary damage, forecast warning system. A total of eight items were derived. Conclusion: In the event of a disaster, decision making will be faster if the checklist proposed in this study is used and applied. In addition, it can be used as the basic data for disaster planners' response plans in case of disasters, and it is expected to be a more clear and quick disaster preparedness and response because it reflects local characteristics.

• Atmosphere
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• v.20 no.3
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• pp.239-246
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• 2010

In this study, the climatological characteristics of the landfall typhoons on North Korea are surveyed to estimate the frequency, the intensity, the track, and their damage. The data for the period of 1951-2008 are used from both RSMC (Regional Specialized Meteorological Center) Tokyo Typhoon Center and NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research), EM-DAT (Emergency Events Database). There are the ten highest frequencies from 1961 to 1965 and is one frequency for the period of both 1966-1979 and 1976-1980 respectively. Even if a clear trend on the frequency of typhoon is not defined, it is noticeable the intensity has been weak since the frequency of TS (Tropical Storm) decreased. In order to figure out both the characteristic of intensity and the relation between the typhoon track and the expansion of North Pacific High (NPH), Typhoon's tracks are classified into three types as follows: (I) landing on the west coast of North Korea through the mainland of China, (II) landing on the west coast of North Korea, (III) landing on a central/eastern part of the Korean peninsula through South Korea. More often than not, the characteristic of Type (I) is the case of a landfall after it becomes extratropical cyclone. Type(II) and Type(III) show a landfall as TS grade, by comparision. On the relation between the typhoon's track and the expansion of NPH analyzed, Type (I) shows the westward expansion while both Type (II) and Type (III) show the northward expansion and development of NPH. This means the intensity of a typhoon landfall on North Korea is variable depending on the development of NPH. Finally, only two cases are found among total five cases in EM-DAT, reportedly that North Korea was damaged. And therefore, the damage by the wind of Prapiroon (the $12^{th}$ typhoon, 2000) and heavy rainfall with Rusa (the $15^{th}$ typhoon, 2002) landing on North Korea was analyzed. Moreover, it is estimated both Prapiroon and Rusa have done badly damaged to North Korea as the economical losses of as much as six billion and five hundred-thousand US dollar, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.564-574
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• 2008

This study investigates a long-term variation of annual maximum surge heights(AMSH) and main characteristics of high surge events, which is influenced by the global warming and intensifying typhoons, using sea level data at Sokcho and Mukho tidal stations over 34 years ($1974{\sim}2007$). It is found that the there is a longterm uptrend of the AMSH at Sokcho (8.3 cm/34yrs) and at Mukho (8.7 cm/34yrs), which is significant within 95% confidence level based on the linear regression. The statistical analysis reveals that 53% of the AMSH occurs during typhoon's event in both tidal stations and the highest surge records are mostly produced by the typhoon. It is concluded that the uptrend in the AMSH is attributed by the increasing typhoon activities globally as well as locally in Korea due to the increased sea surface temperature in tropical oceans. The continuous efforts monitering and predicting the extreme surge events in the future warm environments are required to prevent the growing storm surge damage by the intensified typhoon.