• Title/Summary/Keyword: Severe Storm

Search Result 103, Processing Time 0.022 seconds

Numerical Analysis of Beach Erosion Due to Severe Storms (폭풍에 의해 발생하는 해빈침식에 대한 수치해석)

  • 조원철;표순보
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.12 no.1
    • /
    • pp.19-26
    • /
    • 2000
  • A numerical model is applied for predicting two-dimensional beach and dune erosion during severe storms. The model uses equation of sediment continuity and dynamic equation, governing the on-offshore sediment transport due to a disequilibrium of wave energy dissipation. And the model also uses sediment transport rate parameter K from dimensional analysis instead of that recommended by Kriebel. During a storm, a beach profile evolves to a form where the depth at the surf zone is related to the distance seaward of the waterline. In general, the erosion in the beach profile is found to be sensitive to equilibrium profile parameter, sediment transport rate parameter, storm surge level and breaking wave height.

  • PDF

LARGE-SCALE CURRENTS AND SEA-BOTTOM ELEVATION CHANGE DEVELOPED BY WINTER STORMS

  • Sato, Shinji
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
    • /
    • 1996.10a
    • /
    • pp.89-94
    • /
    • 1996
  • Severe storms are frequently generated in winter along coasts on the Japan Sea side, which are developed by strong northwestern wind caused by periodic passages of low-pressure systems across the sea. The winter storm generally persists for several days, generating strong winds and large waves from northwest. During the storm, strong alongshore currents are also observed in the offshore region, which may continue to flow over a couple of days. (omitted)

  • PDF

Patterns of Water Level Increase by Storm Surge and High Waves on Seawall/Quay Wall during Typhoon Maemi (태풍 매미 내습시 해일$\cdot$고파랑에 의한 호안$\cdot$안벽에서의 수위증가 패턴 고찰)

  • Kang, Yoon-Koo
    • Journal of Ocean Engineering and Technology
    • /
    • v.19 no.6 s.67
    • /
    • pp.22-28
    • /
    • 2005
  • We investigated the characteristics of the overflow/wave overtopping, induced by the storm surge and high waves in Masan bay and Busan Coast during Typhoon 'Maemi', which landed at the southeast coast of the Korean peninsula on September, of 2003, causing a severe inundation disaster. Characteristics of the water level, increase by the overflow / wave overtopping, were discussed in two patterns. One is the increase of water level in the region, located inside of a bay, like Masan fishing port, and the waves are relatively small. The other is in the open sea, in which the waves act directly, as on the seawall in Suyong bay. In the former region, the water level increase was affected by the storm surge, as well as the long period oscillation and waves. In Masan fishing port, about $80\%$ of the water level increase on the quay wall was caused by the storm surge. In the latter one, it was greatly affected by the wave run-up. In Suyong bay, about $90\%$ of the water level increase on the seawall was caused by the wave run-up.

Development of a Web Service based GIS-Enabled Storm-surge Visualization System (웹 서비스 기반 GIS 연동 폭풍.해일 시각화 시스템 개발)

  • Kim, Jin-Ah;Park, Jin-Ah;Park, K.S.;Kwon, Jae-Il
    • Journal of KIISE:Computing Practices and Letters
    • /
    • v.14 no.9
    • /
    • pp.841-849
    • /
    • 2008
  • Natural disaster such as inundation due to the typhoon induced storm-surge has inflicted severe losses on the coastal area. The problem of global warming and sea surface rising has issued and thus influences the increase of frequency and potential power of storm-surge. What we can do is to make intelligent effort to predict and prevent the losses through the early warning and prevention activity from the accurate prediction and forecasting about the time-varying storm-surge height and its arriving time resulted from the numerical simulation with sea observations. In this paper, we developed the web service based GIS-Enabled storm-surge visualization system to predict and prevent the storm-surge disasters. Moreover. for more accurate topography around coastal area and fine-grid storm-surge numerical model, we have accomplished GIS-based coastal mapping through LiDAR measurement.

Can Panax ginseng help control cytokine storm in COVID-19?

  • Choi, Jong Hee;Lee, Young Hyun;Kwon, Tae Woo;Ko, Seong-Gyu;Nah, Seung-Yeol;Cho, Ik-Hyun
    • Journal of Ginseng Research
    • /
    • v.46 no.3
    • /
    • pp.337-347
    • /
    • 2022
  • Coronavirus disease 2019 (COVID-19) is currently a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 are directly associated with hyper-activation of innate immune response that excessively produce pro-inflammatory cytokines and induce cytokine storm, leading to multi-organ-failure and significant morbidity/mortality. Currently, several antiviral drugs such as Paxlovid (nirmatrelvir and ritonavir) and molnupiravir are authorized to treat mild to moderate COVID-19, however, there are still no drugs that can specifically fight against challenges of SARS-CoV-2 variants. Panax ginseng, a medicinal plant widely used for treating various conditions, might be appropriate for this need due to its anti-inflammatory/cytokine/viral activities, fewer side effects, and cost efficiency. To review Panax ginseng and its pharmacologically active-ingredients as potential phytopharmaceuticals for treating cytokine storm of COVID-19, articles that reporting its positive effects on the cytokine production were searched from academic databases. Experimental/clinical evidences for the effectiveness of Panax ginseng and its active-ingredients in preventing or mitigating cytokine storm, especially for the cascade of cytokine storm, suggest that they might be beneficial as an adjunct treatment for cytokine storm of COVID-19. This review may provide a new approach to discover specific medications using Panax ginseng to control cytokine storm of COVID-19.

Monitoring of wind effects on an instrumented low-rise building during severe tropical storm

  • Li, Q.S.;Hu, S.Y.
    • Wind and Structures
    • /
    • v.20 no.3
    • /
    • pp.469-488
    • /
    • 2015
  • A full-scale instrumented low-rise building with gable roof was built at a coastal site with a high incidence of tropical cyclones for monitoring of wind effects on the building during windstorms. This paper presents the field measurements of the wind velocity field around and the wind-induced pressures on the low-rise building during the passage of severe tropical storm Soudelor. Near-ground wind characteristics such as wind speed, wind direction, turbulence intensity, gust factor, turbulence integral length scale and wind velocity spectra were investigated. The wind-induced pressures on the roof of the building were analyzed and discussed. The results revealed that the eave and ridge edges on the roof were subjected to the most severe suction pressures under quartering winds. These suction pressures showed obvious non-Gaussian behavior. The measured results were compared with the provisions of ASCE 7-10 to assess the suitability of the code of practice for the wind-resistant design of low-rise buildings under tropical cyclones. The field study aims to provide useful information that can enhance our understanding of the extreme wind effects on low-rise buildings in an effort to reduce tropical cyclone wind damages to residential buildings.

MAGNETIC PROPERTIES OF INNER MAGNETOSPHERE DURING GEOMAGNETIC STORMS INFERRED FROM A TSYGANENKO MAGNETIC FIELD MODEL

  • Lee, D.Y.;Kim, K.C.;Choi, C.R.;Kim, H.J.
    • Journal of Astronomy and Space Sciences
    • /
    • v.21 no.4
    • /
    • pp.303-314
    • /
    • 2004
  • In this paper we report some properties of inner magnetospheric structure inferred from the T01_s code, one of the latest magnetospheric models by Tsyganenko. We have constructed three average storms representing moderate, strong, and severe intensity storms using 95 actual storms. The three storms are then modelled by the T01_s code to examine differences in magnetic structure among them. We find that the magnetic structure of intense storms is strikingly different from the normal structure. First, when the storm intensity is large, the field lines anchored at dayside longitudinal sectors become warped tailward to align to the solar wind direction. This is particularly so for the field lines anchored at the longitudinal sectors from postnoon through dusk. Also while for the moderate storm the equatorial magnetic field near geosynchronous altitude is found to be weakest near midnight sector, this depression region expands into even late afternoon sector during the severe storm. Accordingly the field line curvature radius at the equator in the premidnight geosynchronous region becomes unusually small, reaching down to a value less than 500 km. We attribute this strong depression and the dawn-dusk asymmetry to the combined effect from the enhanced tail current and the westward expansion/rotation of the partial ring current.

Probabilistic Analysis of Independent Storm Events: 1. Construction of Annual Maximum Storm Event Series (독립호우사상의 확률론적 해석: 1. 연최대 호우사상 계열의 작성)

  • Park, Min-Kyu;Yoo, Chul-Sang
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.11 no.2
    • /
    • pp.127-136
    • /
    • 2011
  • In this study, annual maximum storm events are proposed to determined by the return periods considering total rainfall and rainfall intensity together. The rainfall series at Seoul since 1961 are examined and the results are as follows. First, the bivariate exponential distribution is used to determine annual maximum storm events. The parameter estimated annually provides more suitable results than the parameter estimated by whole periods. The chosen annual maximum storm events show these properties. The events with the biggest total rainfall tend to be selected in the wet years and the events with the biggest rainfall intensity in the wet years. These results satisfy the concept of critical storm events which produces the most severe runoff according to soil wetness. The average characteristics of the annual maximum storm events said average rainfall intensity 32.7 mm/hr in 1 hr storm duration(total rainfall 32.7 mm), average rainfall intensity 9.7 mm/hr in 24 hr storm duration(total rainfall 231.6 mm) and average rainfall intensity 7.4 mm/hr in 48 hr storm duration(total rainfall 355.0 mm).

An Analysis of the Temporal Pattern according to Hydrologic Characteristics of Short-Duration Rainfall (단시간강우의 수문학적 특성에 따른 시간분포 분석)

  • Lee, Jung-Sik;Shin, Chang-Dong;Chang, Jin-Wook
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.6 no.3 s.22
    • /
    • pp.57-68
    • /
    • 2006
  • The objective of this study is to analyze the temporal pattern characteristic of short-duration rainfall defined as a rainfall durations of 6 hours or less by the Huff's 4th quartile distribution. To analyze the temporal pattern characteristic of short-duration rainfall, the rainfall data are classified by rainfall duration and rainfall type(Changma, Typhoon, Severe rain storm, Frontal storm) and change of rainfall segment. Also, the results of this study compared with result of research work of Korea Institute of Construction Technology(1989) and Ministry of Construction & Transportation(2000). The conclusions of this study are as follows; (1) Short-duration rainfall with duration of 6 hours or less is found to be most prevalent frist-quartile storms. (2) In the case of rainfall type, Changma and Severe rain storms and Frontal storm is found second-quartile storms, and Typhoon is found third-quartile storms. (3) In the result by change of sixth segment storms, the type of temporal pattern of rainfall is found to be most prevalent two sixth parts, (4) Comparative analysis of the results shows that shapes of the dimensionless cumulative curves and values are different from those of existing researches.

Numerical Simulation of Coastal Urban Inundation due to Storm Surge and Rainfall (폭풍해일과 강우에 의한 해안 도시 범람 수치모의)

  • Kim, Gun Hyeong;Pyo, Chang Kyu;Yoon, Sung Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.26 no.6
    • /
    • pp.388-396
    • /
    • 2014
  • In this study, numerical simulations are conducted for the inundations due to storm surge and rainfall at Masan City of Korea where severe damages occurred by the typhoon Maemi. A coupled numerical model which can deal with various flow patterns such as storm surge, rainfall and sewer flows is employed. The numerical results show that the inundation area and depth increase significantly when the combined effects of storm surge and rainfall are considered in comparison with those obtained without a rainfall effect. Further numerical simulations are conducted to evaluate the performance of the sea wall being constructed for the coastal defence. The results show that the maximum inundation depths decrease when the sea wall is constructed. However, the duration of inundation becomes longer, because the rainwater on the ground cannot be discharged easily to the sea due to the presence of the sea wall.