• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.41-48
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• 2014

To analyze the surface elevation data of Typhoon Bolaven, simple analytical models are employed to investigate major causes of the storm surges in the west coast of Korea. Although the simple models cannot reproduce the storm surges by Typhoon Bolaven accurately, they are able to provide sufficient evidence of physical processes involved in the storm surges. Surges in islands located at deeper water were mainly driven by typhoon low pressure rather than associated winds. In contrast, bigger storm surge heights more than 1m were recorded in shallow coastal areas during low tide, which were dominantly produced by typhoon winds.

• Journal of the Korean Geographical Society
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• v.49 no.1
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• pp.18-31
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• 2014

In this study, the spatio-temporal patterns of salty wind by typhoon in Jeju Island and their damages to windbreak forests are examined. To investigate these patterns, field trips as well as analyses of meteorological data were conducted after the attack of typhoon BOLAVEN in late August, 2012. Collected data show that salty wind damage in windbreak trees by the typhoon was distinct in the southern and eastern coastal areas due to the southeasterly gusts with less precipitation. Most of trees including Japanese cedar (Cryptomeria japonica) within 8km from the coast as well as pine trees (Pinus thunbergii) along the coasts were damaged by salty water driven by the typhoon, but the magnitude of its damages and recovery rates of damaged vegetation varied by species. These results indicate that prediction and proactive activities for salty wind are needed to reduce its damages to local vegetation particularly before the arrival of a dry typhoon accompanying gusty wind.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.273-283
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Bolaven incident on the west sea of Korea in 2012 are performed using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the various coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the Korea Hydrographic and Oceanographic Agency and the Korea Meteorological Administration. Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the Joint Typhoon Warning Center, and the calculated results are compared and analyzed. The waves and storm surges calculated using JMA-MSM wether field agree well with the observations because of the better reflection of the topography and the pre-background weather field. On the other hand, the calculated results based on the weather fields produced using the JTWC best track information show some limitations of the general trend of the variations of wave and surge heights. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.

• Journal of the Korean Solar Energy Society
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• v.36 no.1
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• pp.27-37
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• 2016

A simple but practical Ensemble Prediction System(EPS) for wind power forecasting was developed and evaluated using the measurement of the offshore meteorological tower, HeMOSU-1(Herald of Meteorological and Oceanographic Special Unite-1) installed at the Southwest Offshore in South Korea. The EPS developed by the Korea Institute of Energy Research is based on a simple ensemble mean of two Numerical Weather Prediction(NWP) models, WRF-NMM and WRF-ARW. In addition, the Kalman Filter is applied for real-time quality improvement of wind ensembles. All forecasts with EPS were analyzed in comparison with the HeMOSU-1 measurements at 97 m above sea level during Typhoon Bolaven episode in August 2012. The results indicate that EPS was in the best agreement with the in-situ measurement regarding (peak) wind speed and cut-out speed incidence. The RMSE of wind speed was 1.44 m/s while the incidence time lag of cut-out wind speed was 0 hour, which means that the EPS properly predicted a development and its movement. The duration of cut-out wind speed period by the EPS was also acceptable. This study is anticipated to provide a useful quantitative guide and information for a large-scale offshore wind farm operation in the decision making of wind turbine control especially during a typhoon episode.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.339-344
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• 2013

Water vapor isotopes can be excellent tools for understanding complex mechanisms in the water cycle and atmospheric hydrological cycle and they can be applied to various fields of paleoclimatology, atmospheric science, hydrogeology, oceanography, and ecohydrology. Thus, studies of global or local transport of water vapor may be able to provide a very useful clue to better understand the movements of water and energy in the atmosphere, hydrosphere and biosphere. In this study, the isotopic compositions of water vapor have been observed for moisture transport during the passage of Typhoon Bolaven at Korea Polar Research Institute (KOPRI), Incheon, in the western part of Korea, from August 27 to August 29, 2012. In the clear sky, the isotopic compositions of water vapor at KOPRI exhibited relatively higher isotopic ratios, which were near isotopic equilibrium with sea surface water (${\delta}^{18}O$=-14‰). On the other hand, a largely depleted isotopic ratios in surface water vapor were observed in association with the passage of Typhoon Bolaven (approximately 10‰ depleted compared to the clear sky). The fact that the isotopic minima in water vapor are encountered during the onset period of the Typhoon Bolaven with increases of relative humidity, which is consistent with, so called, "the amount effect".

• Journal of Environmental Science International
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• v.28 no.4
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• pp.441-454
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• 2019

The present study analyzes the characteristics of 43 typhoons that affected the Korean Peninsula between 2002 and 2015. The analysis was based on 3-second gust measurements, which is the maximum wind speed relevant for typhoon disaster prevention, using a typhoon disaster prevention model. And the distribution and characteristics of the 3-second gusts of four typhoons, RUSA, MAEMI, KOMPASU, and BOLAVEN that caused great damage, were also analyzed. The analysis show that between May and October during which typhoons affected the Korean Peninsula, the month with the highest frequency was August(13 times), followed by July and September with 12 occurrences each. Furthermore, the 3-second gust was strongest at 21.2 m/s in September, followed by 19.6 m/s in August. These results show that the Korean Peninsula was most frequently affected by typhoons in August and September, and the 3-second gusts were also the strongest during these two months. Typhoons MAEMI and KOMPASU showed distribution of strong 3-second gusts in the right area of the typhoon path, whereas typhoons RUSA and BOLAVEN showed strong 3-second gusts over the entire Korean Peninsula. Moreover, 3-second gusts amount of the ratio of 0.7 % in case of RUSA, 0.8 % at MAEMI, 3.3 % at KOMPASU, and 21.8 % at BOLAVEN showed as "very strong", based on the typhoon intensity classification criteria of the Korea Meteorological Administration. Based on the results of this study, a database was built with the frequencies of the monthly typhoons and 3-second gust data for all typhoons that affected the Korean Peninsula, which could be used as the basic data for developing a typhoon disaster prevention system.

• Atmosphere
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• v.26 no.4
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• pp.635-647
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• 2016

The effects of sea surface temperature (SST) gradient induced by the previous typhoon on the following typhoon motion over East Asia have been investigated using Weather Research and Forecasting (WRF) model for the previous Typhoon Bolaven (1215) and following Typhoon Tembin (1214). It was observed that Typhoon Bolaven remarkably reduced SST by about $7^{\circ}C$ at Yellow Sea buoy (YSbuoy). Using the WRF experiments for the imposed cold wake over West of Tembin (WT) and over East of Tembin (ET), this study demonstrates that the effects of eastward SST gradient including cold wake over WT is much significant rather than that over ET in relation to unexpected Tembin's eastward deflection. This difference between two experiments is attributed to the fact that cold wake over WT increases the magnitude of SST gradient under the eastward SST gradient around East Asia and the resultant asymmetric flow deflects Typhoon Tembin eastward, which is mainly due to the different atmospheric response to the SST forcing between ET and WT. Therefore, it implies that the enhanced eastward SST gradient over East Asia results in larger typhoon deflection toward the region of warmer SST according to the location of the cold wake effect. This result can contribute to the improvement of track prediction for typhoons influencing the Korean Peninsula

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.569-582
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• 2012

The heavy rainfalls caused large property damages and human casualties. For example, Changma caused 0.25 billion dollars in damages and 57 deaths and 112 missing by accompanying the torrentially convective heavy rainfall in Seoul, 2011. In addition, TY15 (Bolaven) caused a small damage by bringing a relatively small amount of rainfall and strong wind in Gwanju, 2012. The investigation and analyses of these mesoscale processes of rainfall events for different physical properties using KLAPS for weather environments of the above cases were performed. These typical and ideal meoscale systems by better and more favorable cloud systems were chosen to retrieve rain intensity from Radar and Chullian data. The quantitative rain intensities of Radar and Chullian differ greatly from the ground-based gauge values with underestimating over 50 mm/hr at the peak time of hourly maximum rain intensity about over than 85 mm/hr. However, the Radar rain intensity demonstrated approximately lower than 35 mm/hr, and the Chullian rain intensity less than 60 mm/hr for Changma in Seoul, 2011. For typhoon (TY15, Bolaven) in Gwangju, similarly, the quantitative rain intensities of Radar and Chullian differ from the ground-based gauge values. At the peak time, the hourly maximum rain intensity of ground-based gauge was more than 15 mm/hr. However, the Radar rain intensity showed lower than 5 mm/hr, and the Chullian rain intensity lower than 10 mm/hr. Regarding the above two cases of typhoon and Changma, even though Radar and Chullian rain intensities have been underestimated when compared to the ground-based rain intensity, the distributions of time scale features of both Radar and Chullian rain intensities still delineated a similar tendency of rain intensity distribution of the ground-based gauge data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.1
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• pp.1-8
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• 2019

This research mainly focuses on examining the applicability of the deterministic model SLOSH (Sea, Lake and Overland Surges from Hurricanes) on Seas covering South Korea. Also, a simple bathtub approach which estimates coastal inundation area is validated as a first step of estimating effects of sea-level rise on the coastal cities of South Korea according to climate change. Firstly, the typhoon-induced surges are obtained from the model SLOSH by adopting historical typhoons MAEMI (0314) and BOLAVEN (1215). The results are compared to observational, typhoon-induced surge heights at several tidal stations. The coastal inundation area is estimated by comparing the maximum envelop of waves (MEOW) and the elevation of coastal land. It reproduces well the inundation area. It can be seen that this research gained applicability for estimating further potential coastal inundation with climate changes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5385-5392
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• 2014

Super typhoons develop as a result of meteorological changes. In 2012, Typhoons Bolaven and Denba reached Korea. The maximum instantaneous wind speed of the typhoons reached 60 m/sec. Harbor structures including sofa block sustained damage and loss by the abnormally high waves. In Korea, tetrapod blocks were installed the most for wave dissipating. Nevertheless, a structural evaluation of the tetrapod block has not been performed. This study examined the structural mechanism and weakness part of the tetrapod block under a range of boundary conditions. The block has weakness against a tensile force because it is plain concrete. The joint part of the legs is the most vulnerable to tensile stress. The weakest part can be reduced if the joint part is reinforced as a hunch.