• 한국가시화정보학회지
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• 제5권2호
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• pp.9-13
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• 2007

Typhoon simulation based on dynamical forecasting results is demonstrated by utilizing geodesic model GME (operational global numerical weather prediction model of German Weather Service). It is based on uniform icosahedral-hexagonal grid. The GME gridpoint approach avoids the disadvantages of spectral technique as well as the pole problem in latitude-longitude grids and provides a data structure extremely well suited to high efficiency on distributed memory parallel computers. In this study we made an attempt to simulate typhoon 'NARI' that passed over the Korean Peninsula in 2007. GME has attributes of numerical weather prediction model and its high resolution can provide details on fine scale. High resolution of GME can play key role in the study of severe weather phenomenon such as typhoons. Simulation of future typhoon that is assumed to occur under the global warming situation shows that the life time of that typhoon will last for a longer time and the intensity will be extremely stronger.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_1호
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• pp.23-28
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• 2001

A new numerical weather prediction and dispersion model, the Operational Multi-scale Environment model with Grid Adaptivity(OMEGA) including an embedded Atmospheric Dispersion Model(ADM), is introduced as a next generation atmospheric simulation system for real-time hazard predictions, such as severe weather or the transport of hazardous release. OMEGA is based on an unstructured grid that can facilitate a continuously varying horizontal grid resolution ranging from 100 km down to 1 km and a vertical resolution from 20 -30 meters in the boundary layer to 1 km in the free atmosphere. OMEGA is also naturally scale spanning and time. In particular, the unstructured grid cells in the horizontal dimension can increase the local resolution to better capture the topography or important physical features of the atmospheric circulation and cloud dynamics. This means the OMEGA can readily adapt its grid to a stationary surface, terrain features, or dynamic features in an evolving weather pattern. While adaptive numerical techniques have yet to be extensively applied in atmospheric models, the OMEGA model is the first to exploit the adaptive nature of an unstructured gridding technique for atmospheric simulation and real-time hazard prediction. The purpose of this paper is to provide a detailed description of the OMEGA model, the OMEGA system, and a detailed comparison of OMEGA forecast results with observed data.

• 한국항해항만학회지
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• 제43권5호
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• pp.310-319
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• 2019

With the recent increase in the volume of liquid cargo transportation, there is a need for STS( Ship To Ship) globally. In the case of the STS mooring, the safety assessment should be conducted according to other criteria because mooring is different from the general mooring at the quay, but there is no separate standard in Korea. Thus in this study, STS mooring simulation and sensitivity analysis using OPTIMOOR program, the numerical analysis program, was conducted to identify the characteristics of the STS mooring. The target sea modeled the Yeosu port anchorage in Korea and the target ship was selected as the case of VLCC (Very Large Crude Oil Carrier)-VLCC. Through the numerical simulation and sensitivity analysis, the characteristics of STS mooring were identified. Also based on these results, we focused on establishing the standard for STS mooring safety assessment. Numerical simulation results show that the STS mooring safety can be changed according to a ship's cargo loading condition, pre-tension of mooring line, sea depth, encounter angle with the weather, and the weather condition. Additionally, the risk matrix is prepared to establish the safe external force range in the corresponding sea area. This result can be used to understand the mooring characteristics of STS and contribute to the revision of mooring safety assessment criteria.

• 한국수자원학회논문집
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• 제44권12호
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• pp.967-974
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• 2011

RDAPS 수치예보로부터 생산된 일단위 강우시계열을 바탕으로 유량 예측을 모의하고, 정성적인 중장기 예보를 고려한 ESP 분석을 수행하여 결과를 비교하고 적용성을 검토하였다. 금강유역을 대상으로 ESP, 정성적 기상예보를 고려한 ESP, RDAPS 기상수치예보에의한유량예측결과를평균유출량과비교 분석을 통해각기법별 결과의 개선효과를 평가하였다. 예측 모의 결과 기상정보를 고려한 ESP 방법의 결과가상대적으로 양호한 것으로 분석되었다. 확률예측의 정확도를 평가하기 위한 불일치율(Discrepancy Ratio) 분석 결과에서도 같은 결과를 얻었다. RDAPS 수치예보의 경우 3시간 단위의 누적강수라는 특성이 감안된 시간분해능을 갖는 일단위 시나리오로 개선되거나 장기간 동안 지속적인 모의 평가가 이루어진다면 더욱 정밀한 유량예측을 모의 할 수 있을 것으로 예상된다.

• 대기
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• 제26권2호
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• pp.277-288
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• 2016

Polar lows are intense mesoscale cyclones that mainly occur over the sea in polar regions. Owing to their small spatial scale of a diameter less than 1000 km, simulating polar lows is a challenging task. At King Sejong station in West Antartica, polar lows are often observed. Despite the recent significant climatic changes observed over West Antarctica, adequate validation of regional simulations of extreme weather events such as polar lows are rare for this region. To address this gap, simulation results from a recent version of the Polar Weather Research and Forecasting model (Polar WRF) covering Antartic Peninsula at a high horizontal resolution of 3 km are validated against near-surface meteorological observations. We selected a case of high wind speed event on 7 January 2013 recorded at Automatic Meteorological Observation Station (AMOS) in King Sejong station, Antarctica. It is revealed by in situ observations, numerical weather prediction, and reanalysis fields that the synoptic and mesoscale environment of the strong wind event was due to the passage of a strong mesoscale polar low of center pressure 950 hPa. Verifying model results from 3 km grid resolution simulation against AMOS observation showed that high skill in simulating wind speed and surface pressure with a bias of $-1.1m\;s^{-1}$ and -1.2 hPa, respectively. Our evaluation suggests that the Polar WRF can be used as a useful dynamic downscaling tool for the simulation of Antartic weather systems and the near-surface meteorological instruments installed in King Sejong station can provide invaluable data for polar low studies over West Antartica.

• 한국해안·해양공학회논문집
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• 제32권4호
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• pp.252-261
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• 2020

2018년 남해안에 내습한 태풍 콩레이에 의해 발생한 폭풍해일과 파랑을 일본 기상청의 기상자료인 JMA-MSM 기상 예보 자료를 이용하여 수치모의하고 남동 해안의 항만에서 관측된 폭풍해일 시계열 자료와 비교 검증하였다. 폭풍해일과 동시에 발생하는 파랑에 대해서는 국립해양조사원과 기상청에서 운영하는 해상 파고부이 자료 및 한국해양과학기술원에서 관측한 연안 AWAC 파고계 자료와 비교하여 검증하였다. 기상자료에 따른 폭풍해일과 파랑의 정밀도를 파악하기 위해 미국 합동태풍경보센터인 JTWC에서 제공하는 best track을 이용하여 생성된 기압장과 바람장을 이용한 수치모의를 수행하고 비교 분석하였다. 이 연구를 통하여 정도 높은 폭풍해일과 파랑을 추산하기 위해 신뢰도 높은 기상장이 필수적임을 알 수 있었다.

• 국제초고층학회논문집
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• 제1권2호
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• pp.81-85
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• 2012

Vertical meteorological conditions encountered by super tall buildings, such as wind speed, temperature and humidity, vary due to their height. Therefore, it is necessary to consider these environmental changes to properly estimate the heating and cooling loads, and to minimize the energy demands for HVAC in super tall buildings. This paper aims to analyze how vertical meteorological changes affect heating and cooling loads of super tall buildings by using numerical simulation. A radiosonde, which observes atmospheric parameters of upper air such as wind speed, wind direction, temperature, relative humidity and pressure, was used to provide weather data for the building load simulation. A hypothetical super tall building was used for the simulation to provide quantified characteristics of the heating and cooling loads, comparing the lower, middle and upper parts of the building. The effect of weather data on the heating and cooling loads in super tall building was also discussed.

• 한국해양공학회지
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• 제35권1호
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• pp.13-23
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• 2021

Since the introduction of the mandatory energy efficiency design index (EEDI), several studies have been conducted on the maneuverability of waves owing to the decrease in engine power. However, most studies have used the mean wave force during a single cycle to evaluate maneuverability and investigated the turning performance. In this study, we calculated the external force in accordance with the angle of incidence of the wave width and wavelengths encountered by KVLCC2 (KRISO very large crude-oil carrier) operating at low speeds in regular waves using computational fluid dynamics (CFD). We compare the model test results with those published in other papers. Based on the external force calculated using CFD, an external force that varies according to the phase of the wave that meets the hull was derived, and based on the derived external force and MMG control simulation, a maneuvering simulation model was constructed. Using this method, a weather vaning simulation was performed in regular waves to evaluate the course-keeping ability of KVLCC2 in waves. The results confirmed that there was a difference in the operating trajectory according to the wavelength and phase of the waves encountered.

• 한국전산유체공학회지
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• 제18권1호
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• pp.43-48
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• 2013

The feasibility of a unique greenhouse, named as Gradient Biome, is now being examined extensively in the University of Tokyo. It is a large chamber (length:200m, width:50m, height:40m) in which the weather, such as temperature and humidity, of the tropical zone through to that of the frigid zone on the earth is reproduced with continuous gradient. In the Gradient Biome, ecosystems (mainly plants) corresponding to each weather are introduced and the possible responses of this ecosystems to the expected global warming are to be observed. Since one of the expected responses is the shift of the ecosystem(s) toward the region of suitable environment, there should be no artificial obstacles, which can prevent the shift, inside the Biome. This requirement is not so easy to be satisfied since the environment tends to be homogeneous. This paper presents the results of the numerical studies conducted to find the ways of how the temperature and humidity in the Gradient Biome could be reproduced. One of the contributed solvers of OpenFOAM, which is an open source physics simulation code, was modified and used for the numerical simulations.

• 한국해안·해양공학회논문집
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• 제32권4호
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• pp.273-283
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• 2020

2012년 서해에 내습한 태풍 볼라벤에 의해 발생한 폭풍해일과 파랑을 일본 기상청의 JMA-MSM 기상 예보 자료를 이용하여 수치모의하고, 계산된 해일고를 전국 해안의 항만에서 관측된 폭풍해일 자료와 비교하였다. 폭풍해일과 동시에 발생하는 파랑에 대해서는 해양조사원과 기상청에서 운영하는 해상 파고부이 자료와 비교하여 검증하였다. 기상자료에 따른 폭풍해일과 파랑의 특성을 파악하기 위해 미국 합동태풍경보센터인 JTWC에서 제공하는 best track을 이용하여 생성된 기압장과 바람장을 이용한 수치모의를 수행하고 비교하여 분석하였다. JMA-MSM 기상장은 지형과 선행 배경 기상장이 잘 반영되어 태풍 통과 전후의 전 기간에 걸쳐 파랑과 폭풍해일을 비교적 잘 재현한 반면, JTWC best track을 이용하여 생성된 기상장은 태풍 영향 구역이 협소하여 파랑과 해일고의 시간적 변화 등 전반적인 추세를 반영하지 못하는 등 한계가 있었다. 이 연구를 통하여 폭풍해일과 파랑을 추산하기 위해 신뢰도 높은 기상장이 필수적임을 알 수 있었다.