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해양방사능 물질이동 모델링 고도화
No full text2011년 후쿠시마 제1 원자력발전소 방사능 유출사고 이후, 해양 내 방사성물질의 이동예측에 대한 연구가 진행되고 있다. 향후 발생할 수 있는 방사능 및 오염물질 유출사고에 대비하기 위해 한국해양과학기술원에서는 고해상도 3차원 해양 재분석자료 생산 및 라그랑지안 입자추적모델을 활용한 방사성물질 확산 예측 시스템 마련을 위한 기초연구를 수행하고 있다.
한국해양과학기술원에서는 고해상도(1/12°수평해상도) 북태평양 해양순환 모델을 개발하여 3차원 해양 재분석자료를 생산하고 모델의 성능 검증을 수행하였다. 이를 바탕으로 붕괴, 물과 부유퇴적물 사이의 흡착-탈착, 해저에서의 퇴적-재부유 과정을 고려하는 라그랑지안 입자추적모델을 활용한 방사성물질 확산 예측모델 시스템을 마련하였다. 또한, 다중입경 부유퇴적물 모델 개발, 해양방사능 모델의 병렬화, 부유퇴적물과의 흡탈착 프로세스를 포함하는 새로운 연직 1차원 모델 개발 등 해양방사능 거동모델의 고도화을 수행하여 모델의 예측 성능을 향상시켰다.
본 해양방사능 거동모델의 결과와 한국원자력연구원의 모델 결과를 조합하여 후쿠시마 오염수 방류의 영향에 대한 예측 결과를 도출하였다. 日측의 실시계획안의 삼중수소 농도(연간 배출량 22 TBq 이하로 방류)를 이용하여 시뮬레이션을 수행한 결과, 제주도 남측 우리나라 관할해역에 도달하는 트리튬은 10년 후 약 0.001 Bq/m3의 농도에 수렴하는 것으로 나타났다
북태평양 서안 경계 해역의 상층 열용량 장기 변동 기작 연구
Get PDF학위논문 (박사)-- 서울대학교 대학원 : 지구환경과학부, 2017. 2. 남성현.Winter upper-ocean heat content variability and its causal mechanisms are investigated using observational and reanalysis products in the western North Pacific. The relationship between the East Asian winter monsoon (EAWM) and the North Pacific Oscillation (NPO) and their impact on the sea surface temperature (SST) are nonstationary, with a sudden change at 1987/1988. During the 197387, the EAWM and NPO were significantly correlated to each other, but their correlation practically vanishes during the 19882002. This nonstationary relationship is related to the pronounced decadal weakening of the Siberian high after the 1988 regime shift as well as the concomitant positive NPO-like dipole change. The influence of EAWM and NPO to the winter SST in the study region is significantly decreased after the sudden change near-1990. The upper 400 m heat budget in the western North Pacific is analyzed using outputs from a high resolution ocean general circulation model. Winter heat storage rate on interannual to decadal time scales is mainly determined by oceanic heat advection rather than by net air-sea heat flux. The role of heat advection becomes particularly prominent after the 1990 regime shift in association with the reduced variability of surface heat flux caused by weakened SST variability. The net heat flux acts to dampen temperature anomalies caused by the ocean dynamics principally associated with the meridional shift of the Oyashio Extension front, which is significantly correlated with the West Pacific (WP) and Pacific-North America (PNA) teleconnection patterns.Chapter 1. Introduction 1
1.1. Importance of ocean dynamics in the western North Pacific on climate 1
1.2. KOE region in the western North Pacific 3
1.3. Winter SST variability in the KOE region 4
1.4. Oceanic contributions responsible for SST variability in the KOE region 5
1.5. Atmospheric influences to the themal variability in the western North Pacific 7
1.6. Purpose of the study 8
Chapter 2. Data and method 10
2.1. Observational and reanalysis data sets 10
2.2. Climate indices 11
2.2.1 Definition and acquisition of climate indices 11
2.2.2 Justification of EAWM and NPO indices 12
a. EAWM index 12
b. NPO index 15
2.3. Ocean General Circulation Model (OGCM) data 17
2.3.1 Model description 17
2.3.2 Model validation 19
a. Data sets for validation 19
b. Spatial distribution 20
c. Seasonal and interannual variations 22
2.4. Methods and periods of analyses 24
2.4.1 Linear correlation 24
2.4.2 Linear regressions 25
2.4.3 F-test 25
2.4.4 Regime shift detection 26
2.4.5 Analysis periods 28
Chapter 3. Near-1990 climatic regime shifts in the western North Pacific 29
3.1. Regime-dependent nonstationary relationships among atmospheric indices and ocean 29
3.1.1 Regime shifts of atmospheric circulation patterns and a change in relationship between EAWM and NPO 29
a. Major atmospheric patterns influencing upper ocean variability in the North Pacific and East Asia 29
b. Regime shifts of atmospheric circulation indices 31
c. Changes of relationships between atmospheric indices 34
3.1.2 Relationship between SST and atmospheric forcing patterns 38
a. Long-term relationship between SST, atmospheric forcing patterns and ENSO 38
b. Regime-dependent impact of atmospheric forcing on the SST 43
3.2. Regime-dependent changes of atmospheric states 45
3.2.1 Regime-dependent changes of EAWM (SH) and NPO 45
3.2.2 Evolution of storm track across the regime shift 48
3.2.3 Evolution of tropical influence across the regime shift 52
3.2.4 Upper-level blockings: control factors of SH/EAWM and NPO/WP 55
3.3. A tentative mechanism for the nonstationarity 57
3.3.1 Stationary wave flux 57
3.3.2 Relationship with ENSO 60
3.3.3 Poleward Rossby wave propagation 62
Chapter 4. Epoch-dependent contributions of ocean dynamics to upper-ocean thermal variability 66
4.1. Spatio-temporal variability of upper ocean heat contents in the western North Pacific 66
4.1.1 EOFs and PCs of T400 66
4.1.2 Removing eddy contribution 67
4.2. Heat budget in the upper 400 m of the western North Pacific 70
4.2.1 Heat budget equation for upper ocean 71
a. Heat content as an indicator of ocean state 71
b. Heat budget equation for upper-ocean heat content 71
c. Difficulties to consider the mixed layer temperature budget 73
4.2.2 Mean and seasonal variation 77
a. Time averaged spatial distribution 77
b. Monthly climatologies 80
4.2.3 Winter heat budget in the KOE region for two contrasting epochs 82
a. Nonseasonal variability of heat budget terms 82
b. Epoch-dependent contrasting variability of the heat budget terms 86
4.3. Possible mechanisms for interannual to decadal variability in winter KOE temperature 93
4.3.1 Upper ocean thermal variability due to the meridional shift of oceanic fronts 94
a. Oceanic fronts and KOE T400 variability 94
b. Oceanic fronts and T400 in the western North Pacific 97
c. Oceanic fronts and Sverdrup stream function 98
d. Atmospheric forcing and T400 in the western North Pacific 100
4.3.2 Relationship between winter Qnet and KOE temperature: ocean-to-atmosphere feedback 103
a. Predictors for net surface heat flux 103
b. Decadal changes 107
c. Difference between KOE and SRG regions 110
d. Negative feedback 111
4.3.3 Causes of increased contribution of Qnet during E1 113
Chapter 5. Conclusion 116
5.1. Nonstationary relationship between the EAWM and NPO 116
5.2. Upper-ocean heat content variability in the KOE region 118
5.3. New findings, limitations, and future studies 120
Bibliography 125
국문초록 132Docto
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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