• Atmosphere
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• v.18 no.3
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• pp.159-169
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• 2008

The characteristics of the typhoon's extratropical transition (ET) over the western North Pacific area were investigated using the cyclone phase space (CPS) diagram method suggested by Hart (2003). The data used in this study were the global data assimilation prediction system (GDAPS) and NCEP data set. The number of typhoons selected were 75 cases during 2002 to 2007, and the three parameters were analyzed : the motion relative thickness asymmetry of the storm (B), the upper thermal wind shear and the lower thermal wind shear. Comparing the best-track data provided by the Regional Specialized Meteorological Center /Tokyo, the time of the ET based on CPS was 2~6 hours earlier than the best-track data. And it was shown that the 400- km and 30 kt wind radius of storm for the CPS method were better agreement than the previous suggested radius 500- km.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.465-480
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• 2020

Numerical simulations of the storm surge and the wave induced by the Typhoon Sanba incident on the south coast of Korea in 2012 are conducted using the JMA-MSM forecast weather field, NCEP-CFSR reanalysis weather field, ECMWF-ERA5 reanalysis weather field, and the pressure and wind fields obtained using the best track information provided by JTWC. The calculated surge heights are compared with the time history observed at harbors along the coasts of Korea. For the waves the calculated significant wave heights are compared with the data measured using the wave buoys and the underwater pressure type wave gauge. As a result the JMA-MSM and the NCEP-CFSR weather fields give the highest reliability. The ECMWF-ERA5 gives in general surge and wave heights weaker than the measured. The ECMWF-ERA5, however, reproduces the best convergence belt formed in front of the typhoon. The weather field obtained using JTWC best track information gives the worst agreement.

• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.105-113
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• 2014

Equine herpesvirus type 1 (EHV-1) is an economically important pathogen of horses and exerts its major impact by inducing abortion storms and sporadic abortions in pregnant mares, early neonatal death in foals, and respiratory disease in young horses. Although equine herpesvirus type 4 (EHV-4) rarely causes clinical manifestations of disease in organs other than the respiratory track, isolated cases of myeloencephalopathy and sporadic abortions have been reported in EHV-4 infections. Here, we report an abortion storm in Thoroughbred breeding farms in Jeju island, South Korea. It occurred for 16 days from first abortion to last one. There were no clinical signs prior to abortion and stillbirth in broodmares. Two PCR-primers were made on glycoprotein B gene of EHV-1 and EHV-4 to amplify specific common regions of the viruses. We could detect the virus specific genes in aborted samples by PCR, and concluded that the cause of abortion storm was EHV infection. This report describes the first abortion storm case caused by EHV in Thoroughbred breeding farms in South Korea.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.711-717
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• 2009

In this study, SWMM model is used to reproduce the main storm sewer system located in the Nae-Hang drainage basin of the Mokpo city and keep track of flood discharge. Given the outlet of the reaches border the coastline, this paper has taken the dual-drainage approach to perform inundation simulation, considering both the overflows and inflows at the manholes of the sewer system, and at the same time, taking the impacts of tidal stage into consideration. The following conclusions are reached in this study: First, when planning lowland sewer system alongside the coastline or the riverside, the tidal stage or flood stage need to be considered in the planning and design processes. Second, an analysis that fails to consider overflow and inundation at the manholes may overestimate inundation depth of the flooded area. In other words, in order to estimate flood discharge and flood stage in a lowland storm sewer system, it is desirable to analyze the conveyance capacity of storm sewer system and simulate overflow and inundation at the manholes at the same time.

• Water Engineering Research
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• v.3 no.2
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• pp.113-122
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• 2002

Accurate quantitative forecasting of rainfall for basins with a short response time is essential to predict flash floods. In this study, a Quantitative Flood Forecasting (QFF) model was developed by incorporating the evolving structure and frequency of intense weather systems and by using neural network approach. Besides using radiosonde and rainfall data, the model also used the satellite-derived characteristics of storm systems such as tropical cyclones, mesoscale convective complex systems and convective cloud clusters as input. The convective classification and tracking system (CCATS) was used to identify and quantify storm properties such as lifetime, area, eccentricity, and track. As in standard expert prediction systems, the fundamental structure of the neural network model was learned from the hydroclimatology of the relationships between weather system, rainfall production and streamflow response in the study area. All these processes stretched leadtime up to 18 hours. The QFF model will be applied to the mid-Atlantic region of United States in a forthcoming paper.

• Atmosphere
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• v.19 no.2
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• pp.183-198
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• 2009

The purpose of this study is to summarize the tropical cyclone (TC) activity of 2008 over the western North Pacific including the verification of the official track and intensity forecast errors of these TCs. The TC activity - frequency, Normalized Typhoon Activity (NTA), and life span - was lower than 58-year (1951-2008) average. 22 tropical cyclones of tropical storm (TS) intensity or higher formed in the western North Pacific and the South China Sea in 2008. The total number is less than 58-year average frequency of 26.4. Out of 22 tropical cyclones, 11 TCs reached typhoon (TY) intensity, while the rest 11 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - six STS and five TS storms. One typhoon KALMAEGI (0807) among them affected the Korea peninsula. However, no significant impact - casualty or property damage - was reported. On average of 22 TCs in 2008, the Korea Meteorological Administration (KMA) official track forecast error for 48 hours was 229 km. There was a big challenge for individual cyclones such as 0806 FENGSHEN and 0817 HIGOS presenting significant forecast error, with both intricate tracks and irregular moving speed. The tropical cyclone season in 2008 began in April with the formation of NEOGURI (0801). In May, four TCs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to August. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2008 summertime. The 2008 TC activity has continued the below normal state since mid 1990s which is apparent the decadal variability in TC activity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.1-14
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• 2009

Linear-tracked typhoons were simulated to investigate the effect of parameter sensitivity at Gyeongnam coastal zone. To do this, appropriateness of the linear-tracked MAEMI(0314) was tested and 175 scenarios were simulated on the basis of virtual MAEMI. The results show surge heights are relatively large at Masan and Tongyeong, and it can be attributed to topographical effects. At Masan, 2.5 m-surge height is probable with the same intensity but slightly different track from the real typhoon MAEMI. At the other stations, surge heights induced by real MAEMI are nearly same as the maximum heights of the virtual typhoons, which indicates the real track of the typhoon MAEMI was almost the most severe one. Surge heights caused by the barometric effect are higher than those by the wind effect, and the former effect shows the maximum at the eye of typhoon.

• Atmosphere
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• v.20 no.4
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• pp.451-466
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• 2010

This edition has continued since 2006 tropical cyclone season our effort to provide standard tropical cyclone summaries by the western North Pacific basin and detailed reviews of operationally or meteorologically significant tropical cyclones to document significant challenges and shortfalls in the tropical cyclone warning system to serve as a focal point for research and development efforts. The tropical cyclone season of 2009 in the western North Pacific basin is summarized and the main characteristics of general atmospheric circulation are described. Also, the official track and intensity forecasts of these cyclones are verified. The total number is less than 59-year (1951~2009) average frequency of 26.4. The 2009 western North Pacific season was an inactive one, in which 22 tropical storms generated. Of these, 13 TCs reached typhoon (TY) intensity, while the rest 9 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - three STS and six TS storms. On average of 22 TCs in 2009, the Korea Meteorological Administration official track forecast error for 48 hours was 219 km. There was a big challenge for individual cyclones such as 0902 CHAN-HOM, 0909 ETAU, and 0920 LUPIT resulting in significant forecast error, with both intricate tracks and irregular moving speed. There was no tropical cyclone causing significant direct impact to the country. The tropical cyclone season in 2009 began in May with the formation of KUJIRA (0901). In September and October, ten TSs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to July. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2009 summertime. Year 2009 has continued the below normal condition since mid 1990s which is apparent in the decadal variability in TC activity.

• Atmosphere
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• v.17 no.2
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• pp.207-216
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• 2007

The Moving-nest Typhoon Model (MTM) was installed on the Korea Meteorological Administration (KMA)'s CRAY X1E in 2006 and started its test operation in August 2006 to provide track and intensity forecasts of tropical cyclones. In this study, feasibility of the MTM forecast is compared with the Global Data Assimilation and Prediction System (GDAPS) of the KMA and the operational typhoon forecast models in the Japan Meteorological Agency (JMA), from the sixth tropical cyclone to the twentieth in 2006. Forecast skills in terms of the storm position error of the two KMA models were comparable, but MTM showed a slightly better ability. While both GDAPS and MTM produced larger errors than JMA models in track forecast, the predicted intensity was much improved by MTM, making it comparable to the JMA's typhoon forecast model. It is believed that the Geophysical Fluid Dynamics Laboratory (GFDL) bogus initialization method in MTM improves the ability to forecast typhoon intensity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.492-501
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• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.