• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.564-572
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• 2019

Numerical simulation of the sediment by the Delft3d model was conducted to examine the changes in the sediment budget transport caused by long-term wave changes at the Maengbang beach. Representative waves were generated with input reduction tools using NOAA NCEP wave data for about 40 years, i.e., from January 1979 to May 2019. To determine the adequacy of the model, wave and depth changes were compared and verified using wave and depth data observed for about 23 months beginning in March 2017. As a result of the error analysis, the bias was 0.05 and the root mean square error was 0.23, which indicated that the numerical wave results were satisfactory. Also, the observed change in depth and numerical result were similar. In addition, to examine the effect due to long-term changes in the waves, the NOAA wave data classified into each of the representative wave grades, and then the annual trend of the representative wave was analyzed. After deciding the weight of each wave class considering the changed wave environment in 2100, the amounts of sedimentation, deposition, and the sediment transport budget were reviewed for the same period. The results indicated that the sedimentation pattern did not change significantly compared to the current state, and the amount of the local sediment budget shown in the present state was slightly less. And there has been a local increase in the number of sediment budget transport, but there is no significant difference in the net and amount of sediment movements.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.388-390
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• 2016

본 연구에서는 금강유역의 가뭄과 한반도 주변 지역의 기후 인자들과의 상관관계를 파악하고 이를 바탕으로 기후변화 시나리오를 이용하여 미래의 가뭄을 예측하였다. 1974 - 2015년 동안 11 - 5월에 발생한 강우 자료와 NOAA에서 제공하는 NCEP-NCAR 자료를 이용하여 한반도 주변 기후인자와 금강유역의 강우가 과거 발생한 가뭄과 어떠한 상관관계를 갖는지를 분석하였다. 금강유역의 강우 패턴을 4개의 스테이지로 구분한 후 이를 상태층으로 참고하였으며, 관측 자료는 학습단계에 활용하였다. 이러한 기후인자와 강우 관계의 학습 결과를 바탕으로 기후변화 시나리오를 적용하고 미래의 기후요소를 예측하였으며 이를 통해 미래 금강유역의 가뭄을 예측하였다. 본 연구의 결과는 금강권역 수자원 공급 계획 및 설계의 기초자료로 제공될 수 있으며, 가뭄 대비 대책 사업의 우선순위 결정에 대한 근거 자료로 활용될 수 있을 것으로 기대된다.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.249-249
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• 2002

As Asian Dust's damage and negative effects increase, the need to investigate the weather and surroundings of the source of Asian Dust has been raised. I tried to indicate the source origin and watch changing process of the plants, weather elements in those areas by the means of NOAA AVHRR NOVI and NCEP data.

• Proceedings of the KSRS Conference
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• v.1
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• pp.142-145
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• 2006

The synergism of active and passive microwave techniques for hurricane ocean wind remote sensing is explored. We performed the analysis of Windsat data for Atlantic hurricanes in 2003-2005. The polarimetric third Stokes parameter observations from the Windsat 10, 18 and 37 GHz channels were collocated with the ocean surface winds from the Holland wind model, the NOAA HWind wind vectors and the Global Data Assimilation System (GDAS) operated by the National Center for Environmental Prediction (NCEP). The collocated data were binned as a function of wind speed and wind direction, and were expanded by sinusoidal series of the relative azimuth angles between wind and observation directions. The coefficients of the sinusoidal series, corrected for atmospheric attenuation, have been used to develop an empirical geophysical model function (GMF). The Windsat GMF for extreme high wind compares very well with the aircraft radiometer and radar measurements.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.3
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• pp.103-117
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• 2017

This note provides technical guide on three issues associated with establishing and automatically running regional ocean forecasting systems: (1) a strategy for continuous production of hourly-interval three-day ocean forecast data, (2) the daily download of ocean and atmospheric forecasting data (i.e., HYCOM and NOAA/NCEP GFS data), which are provided by outside institutions and used as initial condition, surface forcing, and boundary data for regional ocean models, and (3) error notifications to numerical model managers through the Short Message Service (SMS). Guidance on dealing with these three issues is illustrated via solutions implemented by the Korea Hydrographic and Oceanographic Agency, since in embarking on this project we found that this procedural information was not readily available elsewhere. This technical guide is based on our experiences and lessons learned during the process of establishing and operating regional ocean forecasting systems for the East Sea and the Yellow and East China Seas over the 5 year period of 2012-2016. The fundamental approach and techniques outlined in this guide are of use to anyone wanting to establish an automatic regional and coastal ocean forecasting system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.21-31
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• 2013

Ecosystem models are mathematical representations of underlying mechanistic relationships among ecological components and processes. Ecosystem modeling is a useful tool to visualize inherent complexities of ecological relationships among components and the characteristic variability in ecological systems, and to quantitatively predict effects of modification of systems due to human activities and/or climate change. A number of interdisciplinary programs in recent 20 to 30 years motivated oceanographic communities to explore and employ systematic and holistic approaches, and as an outcome of these efforts, synthesis and modeling became a popular and important way of integrating lessons learned from many on-going projects. This is a brief review that includes: background information of ecosystem dynamics model; what needs to be considered in building a model framework; biologically-physically coupled processes; end-to-end modeling efforts; and parameterization and related issues.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.618-620
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• 2003

Harmonics of sea surface temperature (SST) in the East Sea and their possible causes are examined by analyzing NOAA/AVHRR data, SSM/I wind speeds, NSCAT wind vectors, and NCEP heat flux data. Detailed spatial structures of amplitudes and phases of the seasonal cycles and their contributions to the total variance of SST have quantitatively. The Subpolar front serves as a boundary between regions of high annual amplitudes (${\geq}$10$^{\circ}$C) in the cold continental region and low amplitudes (${\leq}$10$^{\circ}$C) in the Tsushima Warm Current region. The low phase center of annual cycle is located over a seamount at 132.2$^{\circ}$E, 41.7$^{\circ}$N south of Vladivostok. Semi-annual amplitudes are significantly large leaching over 20% of the annual amplitudes in the Tatarskiy Strait and along the continental shelf off Russian coast in fall and spring, but its forcings are substantially annual. We have shown that fall cooling is attributed by direct and local wind forcing, while spring cooling is remotely forced by cold waters from sea ices in the Tatarskiy Strait.

• Journal of the Korean earth science society
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• v.21 no.5
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• pp.525-540
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• 2000

Global temperature trends of middle and upper tropospheres have been investigated using the data of satellite-observed Microwave Sounding Unit (MSU) channels 2-3(Ch2, Ch3) during the period of 1980-97 and three GCM (NCEP, ECMWF, GEOS) reanalyses during 1981-93. The global, hemispheric and tropical anomalies, computed from the data during the common period, have been intercompared in the following regions; ocean, land, and both ocean and land. The correlation with MSU in midtropospheric temperatures is the best (r=0.81${\sim}$0.95) in ECMWF, particularly over the tropics. The correlations in upper troposphere are lower (r=0.06${\sim}$0.34) due to poor quality of MSU Ch3 data consistent with previous result. The midtropospheric trends during 1981-93, obtained from MSU and three GCMs, show the global warming of 0.01${\sim}$0.18K decade$^{-1}$. The warmest years have been 1987 and 1991 in El Ni${\tilde{n}$o while the coolest 1993 and 1994 in La Ni${\tilde{n}$a. The warming (0.12${\sim}$0.13K decade$^{-1}$) in MSU over global ocean is similar to that over global land. The largest discrepancy in upper troposphere between MSU and GCMs has been found in the transition period (1984. 12-1985. 1) from NOAA 9 to 10, because of a sizable error in the MSU Ch3. The midtropospheric trends near the Korean peninsula during 1981-93 are almost negligible(-0.02K decade$^{-1}$) in MSU, but indicate significant warming (0.25-0.43K decade$^{-1}$) in GCMs. The trends are crosschecked and discussed with other two independent MSU data of Spencer and Christy (1992a, 1992b).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.531-539
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• 2011

It has been widely acknowledged that climate system associated with extreme rainfall events was difficult to understand and extreme rainfall simulation in climate model was more difficult. This study developed a new model for extracting rainfall filed associated with extreme events as a way to characterize large scale climate system. Main interests are to derive location, size and direction of the rainfall field and this study developed an algorithm to extract the above characteristics from global climate data set. This study mainly utilized specific humidity and wind vectors driven by NCEP reanalysis data to define the rainfall field. Geometric first and second moments have been extensively employed in defining the rainfall field in selected zone, and an ellipsoid based model were finally introduced. The proposed geometric moments based ellipsoid model works equally well with regularly and irregularly distributed synthetic grid data. Finally, the proposed model was applied to space-time real rainfall filed. It was found that location, size and direction of the rainfall field was successfully extracted.

• Ocean and Polar Research
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• v.27 no.3
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• pp.237-250
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• 2005

To investigate the air mass modification related with Yeongdong Heavy snowfall events, we examined sensible and latent heat fluxes on the East Sea, the energy exchange between atmosphere and ocean in this study. Sensible and latent heats were calculated by a bulk aerodynamic method, in which NCEP/NCAR reanalysis data and NOAA/AVHRR weekly SST data with high resolution were used. Among winter precipitation events in the Yeongdong region, 19 heavy precipitation events $(1995{\sim}2001)$ were selected and classified into three types (mountain, cold-coastal, and warm types). Mountain-type precipitation shows highly positive anomalies of sensible and latent heats over the southwestern part of the East Set When separating them into the two components due to variability of wind and temperature/ specific Humidity, it is shown that the wind components are dominant. Cold-coastal-type precipitation also shows strong positive anomalies of sensible and latent heats over the northern part and over the central-northern part of the East Sea, respectively. It is shown that the sensible heat anomalies are caused mostly by the decrease of surface air temperature. So it can be explained that cold-coastal-type precipitation is closely related with the air mass modification due to cold air advection over warm ocean surface. But in warm-type precipitation, negative anomalies are found in the sensible and latent heat distributions. From this result, it may be postulated that warm-type precipitation is affected by the internal process of the atmosphere rather than the atmosphere-ocean interaction.