• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.116-118
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• 2023

In recent years, the need for economical and sustainable ship routing has emerged due to the enforced regulations on environmental issues. Despite the development of weather forecasting technology, maritime accidents by rough waves have continued to occur due to incorrect weather forecasts. In this study, onboard measurements are conducted to observe the acutal situation on merchant ships in operation encountering rough waves. The types of measured data include information related to navigation (Ship's position, speed, bearing, rudder angle) and engine (engine revolutions, power, shaft thrust, fuel consumption), weather conditions (wind, waves), and ship motions (roll, pitch, and yaw). These ship experiments was conducted to 28,000 DWT bulk carrier, 63,000 DWT bulk carrier, 20,000 TEU container ship, and 12,000 TEU container ship. The actual ship experiment of each ship is intended to acquire various types of data and utilize them for multi-objective studies related to ship operation. Additionally, in order to confirm the sea conditions, the directional wave spectrum was reproduced using a wave simulation model. Through data collection from ship experiments and wave simulations, various studies could be proceeding such as the measurement for accurate wave information by marine radar and analysis for cargo collapse accidents. In addition, it is expected to be utilized in various themes from the perspective of safety and efficiency in ship operation.

• Atmosphere
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• v.22 no.4
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• pp.489-497
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• 2012

Recently released a top secret document explicitly shows that the early development plan for an earth observation satellite in the USA has a hidden and more important purpose for a concept of 'free space' than the scientific purpose. At that time, the hidden and secret concept imbedded within the early space development plan prevail other national policies of the USA government for purpose of the national security. Under these circumstances, it is quite reasonable to accept a possibility that the meteorological satellites which play a key role in the every area of meteorology and climatology was also born for the hidden purposes. Even it is so, it is quite amazing that the first meteorological satellite is launched in the USA despite of the facts that the major users of the meteorological satellites were not very enthusiastic with the meteorological satellite and the program was not started as a formal meteorological satellite project. This was only possible because of the external socio-political impact caused by the successful launch of the Russian Sputnik satellite and a few key policy developers who favored the meteorological satellite program. It is also interesting to note that the beginning of the first Korean meteorological satellite program was initiated by a similar socio-political influence occurred by the launch of a North Korean satellite.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.351-362
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Maemi incident on the south sea of Korea in 2003 are performed 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 harbours along the coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the measured data. Based on the comparison of surge and wave heights the assessment of the reliability of various weather fields is performed. As a result the JMA-MSM weather fields gives the highest reliability, and the weather field obtained using JTWC best track information gives also relatively good agreement. The ECMWF-ERA5 gives in general surge and wave heights weaker than the measured. The reliability of NCEP-CFSR turns out to be the worst for this special case of Typhoon Maemi. 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 Korean Society of Coastal and Ocean Engineers
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• v.5 no.1
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• pp.11-18
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• 1993

A key element of a successful search and rescue is the correct prediction of the target location. In this paper, new computer models for drift prediction are suggested from the analysis of several methods currently used in other countries. Depending on the availability of the environmental data, users may select a model between the modified versions of U.S. Coast Guard CASP and FLENUMWEACEN SAR. Targets include boats, life rafts and person in water. Life rafts and boats are further classifed. New models are tested and compared with the limited number of field experimental results.

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.575-587
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• 2020

Meteorological phenomena are observed by the Korea Meteorological Administration in a variety of ways (e.g., surface, upper-air, marine, ocean, and aviation). However, there are limits to the meteorological observation of the planetary boundary layer (PBL) that greatly affects human life. In particular, observations using a sonde or aircraft require significant observational costs in economic terms. Therefore, the goal of this study was to measure and analyze the meteorological factors of the vertical distribution of the see-land breeze among local meteorological phenomena using meteorological drones. To investigate the spatial distribution of the see-land breeze, a same integrated meteorological sensor was mounted on each drone at three different points (seaside, bottom of mountain, and mountainside), including the Boseong tall tower (BTT) at the Boseong Standard Weather Observatory (BSWO) in the Boseong region. Vertical profile observations for air temperature, relative humidity, wind direction, wind speed, and air pressure were conducted up to 400 m every 30 minutes from 1100 LST to 1800 LST on August 4, 2018. The spatial characteristics of meteorological phenomena for temperature, relative humidity, and atmospheric pressure were not shown at the four points. Strong winds (~8 m s-1) were observed from the midpoint (~100 m) at strong solar radiation hour, and in the afternoon the wind direction changed from the upper layer at the inland area to the west wind. It is expected that the analysis results of the lower atmospheric layer observed using the meteorological drone may help to improve the weather forecast more accurately.

• 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.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.23-26
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• 2009

효과적인 저수지 운영을 위해 가장 중요한 절차는 저수지 유입량을 적절하게 모의하는 것이다. 실시간 저수지 운영의 경우 기존의 물리적인 강우-유출현상에 기초한 수학적인 모형을 이용해서 유입량을 예측하는데 한계가 있으므로 인공신경망과 같이 자료의 특성에 기반한 모형이 효율적인 대안이 될 수 있다. 본 연구에서는 인공신경망(Artificial neural network, ANN)을 이용하여 실시간 저수지 운영을 위해 현재시간을 기준으로 3시간 후, 6시간 후, 9시간 후, 12시간 후의 유입량을 예측하였다. 본 연구의 대상지역은 한강수계의 화천댐 유역으로 기상청 수치예보자료인 RDAPS(Regional Data Assimilation and Prediction System)자료 중에서 강우예측자료를 사용하였다. RDAPS 강우예측자료를 이용한 예측값 결과와 비교하기 위해 지점 강우자료를 사용하였으며, 이 지점 강우자료는 화천댐 유역에 있는 AWS, 기상청, 국토해양부의 지점자료을 이용하였다. RDAPS 강우예측값만을 이용한 유입량 예측결과가 과거 12시간 강우 누적값을 이용한 유입량 예측값과 비슷한 정확도를 가지는 것을 알 수 있었으며, 자료의 효율적인 취득을 고려해야만 하는 실시간 운영의 경우, RDAPS 강우예측자료와 인공신경망을 이용한 모형이 충분히 효과적인 대안이 될 수 있음을 알 수 있다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.130-137
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• 1992

The previous model of Inchon Bay (Choi 1980) was refined to hindcast/forecast the tides in the Inchon Bay by prescribing the 8 tidal constituents at the open boundaries. A series of hindcast was performed for the period of meterologically calm condition and the simulated results were compared with limited observation showing the reasonable agreements. Preliminary stage of real-time tidal prediction over the whole Inchon Bay were briefly outlined for practical purposes. The established model were further improved by dynamically interfacing, a one dimensional representation of the Han River system. With this model the tidal propagation in the Han River were computed and simulation of recent September. 1990 flood were performed. Discussion for further model development are also described.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.476-483
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• 2007

One of the main function of Ieodo Ocean Research Station is to service the information about the weather and fishing grounds condition which are collected through calibrating convection flow and ocean current around the station. However, due to the influence of the station's structure below sea level, it is difficult to obtain the exact flow data. Therefore, it is required to research on the effect of the structure and the method to evaluate and revise the observed data. In this paper, as a basic study, it deals with the algorithm that simulate the interaction between ocean current and the station structure, followed by discussions about the way to applicate the algorithm. Through 3-dimensional computational fluid dynamics analyses (using Navier-Stokes equations with K-turbulence model), the influence of the station and submerged rocks are quantitatively evaluated, and we would suggest methods how to obtain accurate flow information from the measured rough data.

• Korean Journal of Remote Sensing
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• v.36 no.5_3
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• pp.1037-1051
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• 2020

The accurate monitoring and forecasting of the intensity of tropical cyclones (TCs) are able to effectively reduce the overall costs of disaster management. In this study, we proposed a multi-task learning (MTL) based deep learning model for real-time TC intensity estimation and forecasting with the lead time of 6-12 hours following the event, based on the fusion of geostationary satellite images and numerical forecast model output. A total of 142 TCs which developed in the Northwest Pacific from 2011 to 2016 were used in this study. The Communications system, the Ocean and Meteorological Satellite (COMS) Meteorological Imager (MI) data were used to extract the images of typhoons, and the Climate Forecast System version 2 (CFSv2) provided by the National Center of Environmental Prediction (NCEP) was employed to extract air and ocean forecasting data. This study suggested two schemes with different input variables to the MTL models. Scheme 1 used only satellite-based input data while scheme 2 used both satellite images and numerical forecast modeling. As a result of real-time TC intensity estimation, Both schemes exhibited similar performance. For TC intensity forecasting with the lead time of 6 and 12 hours, scheme 2 improved the performance by 13% and 16%, respectively, in terms of the root mean squared error (RMSE) when compared to scheme 1. Relative root mean squared errors(rRMSE) for most intensity levels were lessthan 30%. The lower mean absolute error (MAE) and RMSE were found for the lower intensity levels of TCs. In the test results of the typhoon HALONG in 2014, scheme 1 tended to overestimate the intensity by about 20 kts at the early development stage. Scheme 2 slightly reduced the error, resulting in an overestimation by about 5 kts. The MTL models reduced the computational cost about 300% when compared to the single-tasking model, which suggested the feasibility of the rapid production of TC intensity forecasts.