• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.129-129
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• 2011

본 연구에서는 강수예보의 선행시간을 확보하기 위하여 기상청 지상관측망 자료뿐만 아니라 MTSAT-1R 위성영상자료와 수치예보모형인 RDAPS(Regional Data Assimilation and Prediction System) 자료를 활용하고, 입력자료 사이의 물리적인 비선형 상관관계를 효과적으로 고려하기 위하여 인경신경망 기법을 적용한 단시간 강수예측모형을 개발하고자 하였다. 또한 강수의 변화특성을 반영하기 위하여 장마기(6월, 7월)와 태풍기(8월, 9월)로 세분화하여 인공신경망 구축을 위한 학습훈련을 수행하였다. 구축된 모형은 서울지점을 대상으로 선행시간 3, 6, 9, 12시간에 대해서 강수예측을 수행하였다. 2006부터 2008년까지 학습훈련 후 2009년 서울지점의 강수예측결과, 장마기의 상관계수는 각 선행시간에 대해서 0.6998, 0.6498, 0.4434, 0.2961, RMSE(Root Mean Square Error)는 0.7605, 2.8431, 3.1973, 4.2147, 태풍기 상관계수는 0.5368, 0.5089, 0.4164, 0.2392, RMSE는 1.2218, 2.3144, 3.9153, 5.2145로 나타났다. 각 선행시간별로 장마기의 예측결과가 태풍기보다 다소 정확하게 도출되었으며, 선행시간 9시간 이후부터는 정확도가 급격히 낮아지는 결과를 얻었다.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2011.11a
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• pp.20-27
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• 2011

A system for fine-resolution long-range weather forecast is introduced in this study. The system is basically consisted of a global-scale coupled general circulation model (CGCM) and Weather Research and Forecast (WRF) regional model. The system makes use of a data assimilation method in order to reduce the initial shock or drift that occurs at the beginning of coupling due to imbalance between model dynamics and observed initial condition. The long-range predictions are produced in the system based on a non-linear ensemble method. At the same time, the model bias are eliminated by estimating the difference between hindcast model climate and observation. In this research, the predictability of the forecast system is studied, and it is illustrated that the system can be effectively used for the high resolution long-term weather prediction. Also, using the system, fine-resolution climatological data has been produced with high degree of accuracy. It is proved that the production of agrometeorological variables that are not intensively observed are also possible.

• Journal of Distribution Science
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• v.21 no.3
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• pp.1-12
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• 2023

Purpose: This study discusses the creative industry phenomenon which has different business characteristics both from resources and production processes to distribution. The study intends to analyze the effect of entrepreneurial orientation and market orientation on business performance by using absorptive capacity as a mediator. Research design, data, and methodology: Using the quantitative method, data were collected from 97 respondents, who are managers or owners of creative industry businesses in Makassar City, South Sulawesi, Indonesia. Data analyzed used Partial Least Square - Structural Equation Model. Results: The results of this study reveal that entrepreneurial orientation has no significant effect on business performance and has indirectly a trough absorptive capacity. Market orientation has a significant effect on business performance and indirectly through absorptive capacity. Another result is that absorptive capacity has a significant effect on business performance. Conclusions: When absorptive capability stresses the assimilation and exploitation of knowledge and market intelligence that has been learned to boost business performance improvements, market orientation and entrepreneurial orientation offer knowledge and experience to business processes including the creation of value distribution in the creative industries.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.204-204
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• 2021

Terrestrial water storage (TWS) includes all components of water (e.g., surface water, groundwater, snow and ice) over the land. So accurately predicting and estimating TWS is important in water resource management. Although many land surface models are used to predict the TWS, model output has errors and biases in comparison to the observation data due to the model deficiencies in the model structure, atmospheric forcing datasets, and parameters. In this study, Gravity Recovery And Climate Experiment (GRACE) satelite TWS data is assimilated in the Community Land Model version 5 with a biogeochemistry module (CLM5.0-BGC) over East Asia from 2003 to 2010 by employing the Ensemble Adjustment Kalman Filter (EAKF). Results showed that TWS over East Asia continued to decrease during the study period, and the ability to simulate the surface water storage, which is the component of the CLM derived TWS, was greatly improved. We further investigated the impact of assimilated TWS on the vegetated and carbon related variables, including the leaf area index and primary products of ecosystem. We also evaluated the simulated total ecosystem carbon and calculated its correlation with TWS. This study shows that how the better simulated TWS plays a role in capturing not only water but also carbon fluxes and states.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.603-616
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• 2016

In this study, the effects of differential heating by land-use types on flow and air temperature at an Seoul Automated Synoptic Observing Systems (ASOS) located at Songwol-dong, Jongno-gu, Seoul was analyzed. For this, a computation fluid dynamics (CFD) model was coupled to the local data assimilation and prediction system (LDAPS) for reflecting the local meteorological characteristics at the boundaries of the CFD model domain. Time variation of temperatures on solid surfaces was calculated using observation data at El-Oued, Algeria of which latitude is similar to that of the target area. Considering land-use type and shadow, surface temperatures were prescribed in the LDAPS-CFD coupled model. The LDAPS overestimated wind speeds and underestimated air temperature compared to the observations. However, a coupled LDAPS-CFD model relatively well reproduced the observed wind speeds and air temperature, considering complicated flows and surface temperatures in the urban area. In the morning when the easterly was dominant around the target area, both the LDAPS and coupled LDAPS-CFD model underestimated the observed temperatures at the Seoul ASOS. This is because the Kyunghee Palace located at the upwind region was composed of green area and its surface temperature was relatively low. However, in the afternoon when the southeasterly was dominant, the LDAPS still underestimated, on the while, the coupled LDAPS-CFD model well reproduced the observed temperatures at the Seoul ASOS by considering the building-surface heating.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1589-1597
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• 2021

Submarine groundwater discharge (SGD) in coastal areas is gaining importance as a major transport route that bring nutrients and trace metals into the ocean. This paper describes the analysis of the seasonal changes and spatiotemporal characteristicsthrough the modeling monthly SGD for 35 years from 1986 to 2020 for the Nakdong river basin. In this study, we extracted 210 watersheds and SGD estimation points using the SRTM (Shuttle Radar Topography Mission) DEM (Digital Elevation Model). The average annual SGD of the Nakdong River basin was estimated to be 466.7 m²/yr from the FLDAS (Famine Early Warning Systems Network Land Data Assimilation System) recharge data of 10 km which is the highest resolution global model applicable to Korea. There was no significant time-series variation of SGD in the Nakdong river basin, but the concentrated period of SGD was expanded from summer to autumn. In addition, it was confirmed that there is a large amount of SGD regardless of the season in coastal area nearby large rivers, and the trend has slightly increased since the 1980s. The characteristics are considered to be related to the change in the major precipitation period in the study area, and spatially it is due to the high baseflow-groundwater in the vicinity of large rivers. This study is a precedentstudy that presents a modeling technique to explore the characteristics of SGD in Korea, and is expected to be useful as foundational information for coastal management and evaluating the impact of SGD to the ocean.

• Atmosphere
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• v.32 no.4
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• pp.323-340
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• 2022

We analyzed the high-resolution wind data of Aircraft-Based Observation from the Mode-Selective Enhanced Surveillance (Mode-S EHS) data in Korea. For assessment of its quality, the Mode-S wind data was compared with the ECMWF ReAnalysis 5 (ERA5) reanalysis and Aircraft Meteorological Data Relay (AMDAR) data for more than 3-months from 7 May 2021 to 24 August 2021 near Incheon International Airport, Korea. Considering that the AMDAR reports are not provided by all commercial aircraft, total number of the Mode-S derived wind data with a second sampling rate was about twice larger than that of available AMDAR wind data. After the quality control procedures by removing erroneous samples, it was found that the root mean square errors (RMSEs) of the Mode-S retrieved winds are similar to that from the AMDAR winds. In particular, between 550 and 650 hPa levels, RMSE of the Mode-S (AMDAR) zonal wind against ERA5 data was about 2.3 m s^-1 (1.9 m s^-1), and those increased to 3.3 m s^-1 (2.4 m s^-1) in 200~500 hPa levels. A similar trend was found in the meridional wind, but a distinct positive mean bias of 2.16 m s^-1 was observed between 875 and 1,000 hPa levels. Winds retrieved from the Mode-S also showed a good agreement directly with AMDAR data. As the Mode-S provides a large amount of data with a reliable quality, it can be useful for both data assimilation in the numerical weather prediction model and situational awareness of wind and turbulence for aviation safety in Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.114-118
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• 2005

본 연구에서는 특정 유역의 토양수분 상태, 한계유출량(threshold runoff) 및 단기 기상예보 자료 등으로부터 돌발홍수능(Flash Flood Guidance, FFG)을 계산할 수 있는 실시간 돌발홍수 예경보시스템을 개발하기 위해 한강유역을 대상으로 DEM 자료를 이용하여 미세 소유역을 구분하고 하도단면 특성을 고려한 제방 월류 유량 개념을 기초로 고해상도 소유역 단위의 한계유출량을 산정하고, 중규모 TOPMODEL의 토양수분 모델을 통해 임의 상태의 토양수분을 추정할 수 있도록 개발하였다 또한, FFG 시스템의 기상학적 구성요소 개발을 위해 레이더 강우 추정을 편차보정 기법을 통해 계산하였다. 상술된 계산결과를 바탕으로 2003년 7월의 호우사상에 대한 유역 및 격자기반의 FFG를 산정하였고, 이들 결과는 기상청의 RDAFS(Regional Data Assimilation and Prediction System) 단기 수치예보 자료의 지속시간별 예측강수량을 활용하여 돌발홍수 발생에 대한 사례연구를 수행하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.221-225
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• 2006

본 연구에서는 한계유출량(threshold runoff), 특정 유역의 토양수분 상태 및 단기 기상예보 자료 등으로부터 한강유역의 돌발홍수능(Flash Flood Guidance, FFG)을 계산할 수 있는 한국형 돌발홍수 예경보시스템을 개발하였다. 한강유역의 DEM 자료를 이용하여 미세 소유역을 구분하고 하도단면 특성을 고려한 제방 월류유량 개념을 기초로 고해상도 미세 소유역 단위의 지속시간별 한계유출량을 산정하였고, Sacramento 토양수분 모델을 통해 임의 시간의 토양수분 상태를 실시간으로 추정할 수 있는 돌발홍수 모델의 수문학적 구성요소를 개발하였다. 또한, FFG 시스템의 기상학적 구성요소로 레이더 강우 추정을 추계 동역학적 편차보정 기법을 통해 계산하였다. 상술된 수문 및 기상학적 구성요소를 바탕으로 2003년 7월 및 2004년 8월의 호우사상에 대한 유역기반의 FFG를 산정하였고, 기상청의 RDAPS(Regional Data Assimilation and Prediction System) 단기 수치예보 자료의 지속시간별 예측강수량을 활용하여 돌발홍수 발생 가능성에 대한 사례연구를 수행하였다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.301-309
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• 2009

This study focuses on event-driven social media (EDSM), which supports the production of unique cultural items of small groups by satisfying the conflicting desires of distinctiveness and assimilation that small groups possess. EDSM is a system which promotes the production of idioculture through small group interaction by using an actual event in which people participate in small groups. By setting up an EDSM system in a university festival in which 10,000 to 15,000 people gather in small groups, idioculture production was tested for approximately eight hours and a half. Interaction records gathered from the test, as well as focus group interview data garnered soon after were used to analyze usage patterns of EDSM, types of idiocultures produced, and resulting factors of user experience. Through this, considerations upon designing future EDSM were proposed.