고해상도 기후예측시스템의 표층해류 예측성능 평가

이효미,장필훈,강기룡,강현석,김윤재 한국해양과학기술원 2018 Ocean and Polar Research Vol.40 No.3

In the present study, we assess the GloSea5 (Global Seasonal Forecasting System version 5) near-surface ocean current forecasts using globally observed surface drifter dataset. Annual mean surface current fields at 0-day forecast lead time are quite consistent with drifter-derived velocity fields, and low values of root mean square (RMS) errors distributes in global oceans, except for regions of high variability, such as the Antarctic Circumpolar Current, Kuroshio, and Gulf Stream. Moreover a comparison with the global high-resolution forecasting system, HYCOM (Hybrid Coordinate Ocean Model), signifies that GloSea5 performs well in terms of short-range surface-current forecasts. Predictions from 0-day to 4-week lead time are also validated for the global ocean and regions covering the main ocean basins. In general, the Indian Ocean and tropical regions yield relatively high RMS errors against all forecast lead times, whilst the Pacific and Atlantic Oceans show low values. RMS errors against forecast lead time ranging from 0-day to 4-week reveal the largest increase rate between 0-day and 1-week lead time in all regions. Correlation against forecast lead time also reveals similar results. In addition, a strong westward bias of about 0.2 m s-1 is found along the Equator in the western Pacific on the initial forecast day, and it extends toward the Equator of the eastern Pacific as the lead time increases.

글로벌 마인드 역량의 구성요인 탐색 및 지수 개발

이효미,김명소,한영석 한국산업및조직심리학회 2011 한국심리학회지 산업 및 조직 Vol.24 No.3

본 연구의 목적은 최근 기업조직에서 핵심 역량으로 부각되고 있는 글로벌 마인드 역량에 대한 구성요인을 탐색하고, 역량 수준을 진단하기 위한 도구개발 및 타당성을 검증하기 위한 것이다. 이를 위해 기존 연구들을 바탕으로 글로벌 마인드를 개념화(conceptualization)와 맥락화(contextualization)의 상위차원을 선정하여 문항들을 수집 및 개발하고, 중복적인 문항들을 제외한 후 62개의 행동기술문을 선정하였다. 이들 행동기술문에 대해 직장인 380명과 대학생 372명의 총 752명을 대상으로 자기평가를 실시한 후, 우선 직장인을 대상으로 탐색적 요인분석을 실시하였다. 1, 2차 요인분석 결과, 개념화에 해당하는 개방적 사고, 전략적 사고, 세계융합 마인드와 맥락화의 다양성 추구, 외부세계 이해, 주도적 적응성, 배려행동의 총 7개 요인이 도출되었다. 이러한 위계적 요인구조의 적합성을 검증하기 위해 대학생을 대상으로 확인적 요인분석을 실시한 결과, 부합도 지수들이 수용 가능한 수준으로 나타나 글로벌 마인드의 요인구조가 지지되었으며, 한 요인별 6개씩 최종적으로 42개의 문항이 선정되었다. 또한, 해외 거주 경험, 외국어 수준, 조직의 글로벌 관련성 지각, 글로벌 역량 및 글로벌 정체성 수준 등의 다양한 변인들과 상관분석을 실시한 결과, 대체적으로 유의미한 정적 상관을 보였다. 글로벌 정체성과 전반적인 글로벌 역량수준을 준거로 다중회귀분석을 실시한 결과, 글로벌 정체성에는 세계융합 마인드, 전략적 사고, 다양성 추구, 주도적 적응성 요인이, 전반적인 글로벌 역량 수준에서는 외부세계 이해, 다양성 추구, 주도적 적응성 요인이 유의미한 예측변인으로 도출되었다. 이와 함께, 위계적 회귀분석 결과 글로벌 정체성과 글로벌 역량수준 예측 시 일반적인 선발장면에서 빈번하게 활용되고 있는 외국어 능력에 추가하여 글로벌 마인드의 증분 타당도도 지지되었다. 마지막으로, 각 역량의 상대적 영향력을 조사하여 글로벌 마인드 지수를 개발하였으며, 이러한 결과를 토대로 본 연구의 의의와 제한점 및 향후 연구과제에 대해 논의하였다.

클로로필 모의 개선을 위한 NEMO-TOPAZ 민감도 실험

이효미,문병권,박종연,위지은,정현채,변영화,임윤진,이조한 한국기상학회 2019 한국기상학회 학술대회 논문집 Vol.2019 No.10

CCMI 모델들의 대류권 모의성능 평가

이효미,박효진,위지은,문병권 한국기상학회 2019 한국기상학회 학술대회 논문집 Vol.2019 No.4

Multivariable Integrated Evaluation of GloSea5 Ocean Hindcasting

이효미,문병권,김한경,위지은,박효진,장필훈,이조한,김윤재 한국지구과학회 2021 한국지구과학회지 Vol.42 No.6

Seasonal forecasting has numerous socioeconomic benefits because it can be used for disaster mitigation. Therefore, it is necessary to diagnose and improve the seasonal forecast model. Moreover, the model performance is partly related to the ocean model. This study evaluated the hindcast performance in the upper ocean of the Global Seasonal Forecasting System version 5-Global Couple Configuration 2 (GloSea5-GC2) using a multivariable integrated evaluation method. The normalized potential temperature, salinity, zonal and meridional currents, and sea surface height anomalies were evaluated. Model performance was affected by the target month and was found to be better in the Pacific than in the Atlantic. An increase in lead time led to a decrease in overall model performance, along with decreases in interannual variability, pattern similarity, and root mean square vector deviation. Improving the performance for ocean currents is a more critical than enhancing the performance for other evaluated variables. The tropical Pacific showed the best accuracy in the surface layer, but a spring predictability barrier was present. At the depth of 301 m, the north Pacific and tropical Atlantic exhibited the best and worst accuracies, respectively. These findings provide fundamental evidence for the ocean forecasting performance of GloSea5.

새롭게 개발된 NEMO-TOPAZ의 생지화학 모의 특징

이효미,문병권,정현채,변영화,임윤진,이조한 한국기상학회 2019 한국기상학회 학술대회 논문집 Vol.2019 No.4

Development of the UKESM-TOPAZ Earth System Model (Version 1.0) and Preliminary Evaluation of its Biogeochemical Simulations

이효미,문병권,정현채,박종연,심성보,라나리,김아현,염성수,하종철,변영화,성현민,이조한 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.3

Earth system models (ESMs) comprise various Earth system components and simulate the interactions between these components. ESMs can be used to understand climate feedbacks between physical, chemical, and biological processes and predict future climate. We developed a new ESM, UKESM-TOPAZ, by coupling the UK ESM (UKESM1) and the Tracers of Phytoplankton with Allometric Zooplankton (TOPAZ) biogeochemical module. We then compared the preliminary simulated biogeochemical variables, which were conducted over a period of 70 years, using observational and existing UKESM1 model data. Similar to UKESM1, the newly developed UKESM-TOPAZ closely simulated the relationship between the El Niño-Southern Oscillation and chlorophyll concentration anomalies during the boreal winter. However, there were differences in the chlorophyll distributions in the eastern equatorial Pacific between the two models, which were due to dissolved iron, as this value was higher in UKESM-TOPAZ than in UKESM1. In a mean field analysis, the distributions of the major marine biogeochemical variables in UKESM-TOPAZ (i.e., nitrate, silicate, dissolved oxygen, dissolved inorganic carbon, and alkalinity) were not significantly different from those of UKESM1, likely because the models share the same initial conditions. Our results indicate that TOPAZ has a simulation performance that does not lag behind UKESM1’s basic biogeochemical model (Model of Ecosystem Dynamics, nutrient Utilisation, Sequestration, and Acidification; MEDUSA). The UKESM-TOPAZ model can simulate the variability of the observed Niño 3.4 and 4 indices more closely than UKESM1. Thus, the UKESM-TOPAZ model can be used to deepen our understanding of the Earth system and to estimate ESM uncertainty.

CCMI 모델 모의성능 평가

이효미,박효진,위지은,문병권 한국기상학회 2018 한국기상학회 학술대회 논문집 Vol.2018 No.10

Impact of Iron Scavenging and Desorption Parameters on Chlorophyll Simulation in the Tropical Pacific within NEMO-TOPAZ

이효미,Byung-Kwon Moon,박종연,김한경,정현채,위지은,박효진,변영화,임윤진,이조한 한국지구과학회 2021 한국지구과학회지 Vol.42 No.4

Ocean biogeochemistry plays a crucial role in sustaining the marine ecosystem and global carbon cycle. To investigate the oceanic biogeochemical responses to iron parameters in the tropical Pacific, we conducted sensitivity experiments using the Nucleus for European Modelling of the Ocean–Tracers of Ocean Phytoplankton with Allometric Zooplankton (NEMO-TOPAZ) model. Compared to observations, the NEMO-TOPAZ model overestimated the concentrations of chlorophyll and dissolved iron (DFe). The sensitivity tests showed that with increasing (+50%) iron scavenging rates, chlorophyll concentrations in the tropical Pacific were reduced by approximately 16%. The bias in DFe also decreased by approximately 7%; however, the sea surface temperature was not affected. As such, these results can facilitate the development of the model tuning strategy to improve ocean biogeochemical performance using the NEMOTOPAZ model.

Future Extreme Temperature and Precipitation Mechanisms over the Korean Peninsula Using a Regional Climate Model Simulation

이효미,문병권,위지은 한국지구과학회 2018 한국지구과학회지 Vol.39 No.4

Extreme temperatures and precipitations are expected to be more frequently occurring due to the ongoing global warming over the Korean Peninsula. However, few studies have analyzed the synoptic weather patterns associated with extreme events in a warming world. Here, the atmospheric patterns related to future extreme events are first analyzed using the HadGEM3-RA regional climate model. Simulations showed that the variability of temperature and precipitation will increase in the future (2051-2100) compared to the present (1981-2005), accompanying the more frequent occurrence of extreme events. Warm advection from East China and lower latitudes, a stagnant anticyclone, and local foehn wind are responsible for the extreme temperature (daily T>38°C) episodes in Korea. The extreme precipitation cases (>500 mm day−1) were mainly caused by mid-latitude cyclones approaching the Korean Peninsula, along with the enhanced Changma front by supplying water vapor into the East China Sea. These future synoptic-scale features are similar to those of present extreme events. Therefore, our results suggest that, in order to accurately understand future extreme events, we should consider not only the effects of anthropogenic greenhouse.