• 제목/요약/키워드: atmosphere model

검색결과 1,172건 처리시간 0.033초

전산유동해석을 통한 산악 지역의 고해상도 풍력자원 특성에 관한 수치연구 (A Numerical Study on the Characteristics of High Resolution Wind Resource in Mountainous Areas Using Computational Fluid Dynamic Analysis)

  • 이순환
    • 한국지구과학회지
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    • 제32권1호
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    • pp.46-56
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    • 2011
  • 전산유동 수치모형을 이용하여 다양한 대기안정도 상태하에서 부산광역시내 승학산과 구덕산의 초고해상도 풍력자원을 평가하였다. 연구에 사용된 수치모형은 중규모와 미규모 기상현상의 재현에 널리 사용되는 전산유동 수치모형인 A2C이다. 대기안정도가 강할 때, 위치에너지의 크기가 상대적으로 강해지기 때문에 산을 넘어가는 경향이 나타난다. 반면 대기안정도가 약해지면서 산악후면의 후류 발생이 증대되며, 난류에너지가 증가한다. 그리고 연평균 풍력밀도, 난류운동에너지, 연직 바람전단력 분석을 통하여 구덕산 정상의 남쪽 부근이 다른 구역보다 가용 풍력자원이 풍부함을 확인하였다.

PRISM을 이용한 30 m 해상도의 상세 일별 기온 추정 (Estimation of Fine-Scale Daily Temperature with 30 m-Resolution Using PRISM)

  • 안중배;허지나;임아영
    • 대기
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    • 제24권1호
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    • pp.101-110
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    • 2014
  • This study estimates and evaluates the daily January temperature from 2003 to 2012 with 30 m-resolution over South Korea, using a modified Parameter-elevation Regression on Independent Slopes Model (K-PRISM). Several factors in K-PRISM are also adjusted to 30 m grid spacing and daily time scales. The performance of K-PRISM is validated in terms of bias, root mean square error (RMSE), and correlation coefficient (Corr), and is then compared with that of inverse distance weighting (IDW) and hypsometric methods (HYPS). In estimating the temperature over Jeju island, K-PRISM has the lowest bias (-0.85) and RMSE (1.22), and the highest Corr (0.79) among the three methods. It captures the daily variation of observation, but tends to underestimate due to a high-discrepancy in mean altitudes between the observation stations and grid points of the 30 m topography. The temperature over South Korea derived from K-PRISM represents a detailed spatial pattern of the observed temperature, but generally tends to underestimate with a mean bias of -0.45. In bias terms, the estimation ability of K-PRISM differs between grid points, implying that care should be taken when dealing with poor skill area. The study results demonstrate that K-PRISM can reasonably estimate 30 m-resolution temperature over South Korea, and reflect topographically diverse signals with detailed structure features.

Carbon Storage in Aboveground, Root, and Soil of Pinus densiflora Stand in Six Different Sites, Korea

  • Park, Gwan-Soo;Choi, Jaeyong;Lee, Kyung-Hak;Son, Young-Mo;Kim, Rae-Hyun;Lee, Hang-Goo;Lee, Sang-Jin
    • 한국환경복원기술학회지
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    • 제12권2호
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    • pp.1-9
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    • 2009
  • Due to the increase of carbon dioxide in the atmosphere and global warming, the importance of forest ecosystems, as a place of carbon accumulation and emission, has received a great amount of recognition lately. This study was performed to help understand and provide the current status of carbon cycle in the pinus densiflora stand, Korea. The samples were collected from average 35-years-old Pinus densifiora rands in Gongju, Youngdong, Chungsan, Muju, Mupung, and Jangsu regions. Total thirty aboveground sample trees were cut, and ten roots were sampled, and soil samples were collected. Average carbon concentrations in foliage, branch, stem bark, stem wood, and root were 55.7%, 56.0%, 56.0%, 57.3%, and 56.5%, respectively. Carbon content was estimated by the model $Wt=aD^b$ where Wt is oven-dry weight in kg and D is DBH in cm. Total carbon content (aboveground and root) was 42.39tonC/ha in the Pinus densiflora stand. The proportion of each tree component to total carbon content was high in order of stemwood, root, branch, stem bark, and foliage. Total net primary production (aboveground and root) was estimated at 6.51tonC/ha/yr in Pinus densiflora stand. The proportion of each tree component to total net primary carbon content was high in order of sternwood, root, branch, foliage and stembark. Soil carbon contents in the study sites was 43.51tonC/ha at 0-50cm soil depth.

METRI AGCM의 복사 모수화 개선에 따른 겨울철 기후모의의 특징적 변화 (Changes in the Characteristics of Wintertime Climatology Simulation for METRI AGCM Using the Improved Radiation Parameterization)

  • 임한철;변영화;박수희;권원태
    • 대기
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    • 제19권2호
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    • pp.127-143
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    • 2009
  • This study investigates characteristics of wintertime simulation conducted by METRI AGCM utilizing new radiation parameterization scheme. New radiation scheme is based on the method of Chou et al., and is utilized in the METRI AGCM recently. In order to analyze characteristics of seasonal simulation in boreal winter, hindcast dataset from 1979 to 2005 is produced in two experiments - control run (CTRL) and new model's run (RADI). Also, changes in performance skill and predictability due to implementation of new radiation scheme are examined. In the wintertime simulation, the RADI experiment tends to reduce warm bias in the upper troposphere probably due to intensification of longwave radiative cooling over the whole troposphere. The radiative cooling effect is related to weakening of longitudinal temperature gradient, leading to weaker tropospheric jet in the upper troposphere. In addition, changes in vertical thermodynamic structure have an influence on reduction of tropical precipitation. Moreover, the RADI case is less sensitive to variation of tropical sea surface temperature than the CTRL case, even though the RADI case simulates the mean climate pattern well. It implies that the RADI run does not have significant improvement in seasonal prediction point of view.

우리나라 인근과 유럽의 계절에 따른 강수와 기온의 관계 및 RCP8.5 시나리오에 기반한 미래 전망 (The Seasonal Correlation Between Temperature and Precipitation Over Korea and Europe and the Future Change From RCP8.5 Scenario)

  • 김진욱;부경온;심성보;권원태;변영화
    • 대기
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    • 제27권1호
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    • pp.79-91
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    • 2017
  • It is imperative to understand the characteristics of atmospheric circulation patterns under the climate system due to its impact on climatic factors. Thus this study focused on analyzing the impact of the atmospheric circulation on the relationship between precipitation and temperature regionally. Here we used monthly gridded observational data (i.e., CRU-TS3.2, NOAA-20CR V2c) and HadGEM2-AO climate model by RCP8.5, for the period of 1960~1999 and 2060~2099. The experiment results indicated that the negative relationship was presented over East Asia and Europe during summer. On the other hand, at around Korea (i.e. EA1: $31^{\circ}N{\sim}38^{\circ}N$, $126^{\circ}E{\sim}140^{\circ}E$) and Northwestern Europe (i.e. EU1: $48^{\circ}N{\sim}55^{\circ}N$, $0^{\circ}E{\sim}16^{\circ}E$) in winter, strong positive relationship dominate due to warm moist advection come from ocean related to intensity variation of the East Asian winter monsoon (EAWM) and North Atlantic Oscillation (NAO), respectively. It was found that values of positive relation in EA1 and EU1 at the end of the 21st century is regionally greater than at the end of 20th century during winter since magnitude of variation of the EAWM and NAO is projected to be greater in the future as result of simulation with RCP 8.5. Future summer, the negative correlations are weakened in EA1 region while strengthened in EU1 region. For better understanding of correlations with respect to RCP scenarios, a further study is required.

A Study on the Moderating Effect that Value Congruence Influences Organizational Performance

  • LEE, Joon-Pyo
    • 산경연구논집
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    • 제11권3호
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    • pp.51-62
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    • 2020
  • Purpose - This study examined the relationship between individual creativity and its related variables to observe how individual creativity contributes to organizational performance. In addition, this study strived to explore how to maximize the utilization of individual creativity and innovate the structure of the organization itself so that teams and organizations can respond more effectively to new rising trends. this study aimed to examine whether the value congruence between individuals and organizations (propensity congruence, goal congruence has a significant impact on knowledge sharing and innovation behavior as dependent variables by exerting individual creativity and synergy as independent variables. Research design, data and methodology - SPSS 24.0 program were used to analyze the data. Descriptive Statistics and correlation analysis were performed, and the reliability factor (Cronbach's α) was calculated. Afterwards, we analyzed the moderating effects of structural equation model analysis and hierarchical regression analysis. The number of samples used in the study were 309 copies. Results - First, Individual creativity had a positive effect on knowledge sharing and innovative behavior. In other words, it was confirmed that decision-making processes fused with individual creativity could create an atmosphere of knowledge sharing and transform the organization. Second, value congruence adjusted the influence of individual creativity on knowledge sharing and innovation behavior. Conclusions - First, it is important for managers to recognize the value and secure the pool of creative talents who will be a potential future basic source of organizational success and competitive advantage. Second, managers should be able to identify those with creative talents and expertise, and use them to increase their knowledge sharing performance, while also developing emotional and motivational creativity. Third, in order improve knowledge sharing performance, managers should pay attention to the emotional aspect of creativity. Fourth, managers should strive to create an environment that is beneficial for the reinforcement of individual self-management capabilities. Fifth, managers should be able to develop decision-making processes to develop potential creativity and encourage creative thinking, opinions, or solutions. Sixth, managers should promote the dissemination and integration of new knowledge based on the creative views and attitudes of team members.

패션 컬렉션과 예술에 나타난 허무주의 표현 분석 (Analysis of Expressions on Nietzsche's Nihilism in Fashion Collection & Arts)

  • 이혜원;김민자
    • 복식
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    • 제65권4호
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    • pp.76-90
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    • 2015
  • Based on a concept of Nietzschean nihilism, this study aimed at interpreting the nihilism in arts and its expressions, also analyzing the modern fashion collection from the same angle. The research was centered on arts after 1980, when post-modern formal destruction expanded in earnest and on the fashion collection after the 20th century, easily accessible to data. Particularly, it set 1994 nihilism collection by Alexander McQueen, a representative nihilist fashion designer as a starting point. Nietzsche mentioned that true arts may be achieved when Apollonian characteristics including a bodily sensory system and an idealization process and Dionysian characteristics including every human feeling are integrated. Besides, he emphasized the importance of an artist being represented as an image of ${\ddot{U}}bermensch$. The ${\ddot{U}}bermensch$ image, reflected in arts and artistic nihilism, represents themes of violence/death, realistic/unrealistic expressions, human body/inhuman aversion materials and the transmutation of a form. Fashion collection expressions, owing to the special characteristic of the show form unlike other arts, were segmented as a realistic ${\ddot{U}}bermensch$ image using a model in a theme, expression, material and form. The theme of violence/death was divided into the death of human and a society. Human life/death was expressed as destruction of human weakness and self-identity, sexual objectification and violence, and social death as destruction and conflict of a class, nation, culture and nature. As for the expression, it was divided into the realistic expression of the primitive/natural and directing of an unrealistic atmosphere using a show.

북한 지역의 산맥군이 영동 지역의 겨울철 강설 분포에 미치는 영향에 관한 수치 연구 (A Numerical Case Study Examining the Orographic Effect of the Northern Mountain Complex on Snowfall Distribution over the Yeongdong Region)

  • 이재규;김유진
    • 대기
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    • 제19권4호
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    • pp.345-370
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    • 2009
  • Numerical experiments using the Weather Research and Forecasting (WRF) model were done to identify the role of the mountain ranges in the northern part of the Peninsula (referred as "the northern mountain complex"), in the occurrence of two heavy snowfall events over the Yeongdong region on 7-8 December 2002 and 20-21 January 2008. To this end, control simulations with the topography of the northern mountain complex and other simulations without the topography of the mountain complex were performed. It was revealed that the amount of snowfall over the Yeongdong region from the control simulation much more exceeded that of the simulation without the topography of the mountain complex. This increase of the snowfall amount over the Yeongdong region can be explained as follows: As the upstream flow approached the northern mountain complex, it deflected around the northern mountain complex due to the blocking effect of the mountains with a low Froude number less than ~0.16. This lead to the strengthening of northeasterly over the East Sea and over the Yeongdong region. The strong northeasterly is accompanied with much more snowfall over the Yeongdong region by intensifying air-mass modification over the sea and the orographic effect of the Taeback mountains. Thus, it was concluded that the topography of the northern mountain complex is one of the main factors in determining the distribution and amount of precipitation in the Yeongdong region when there is an expansion of the Siberian High toward the East Sea.

중간 속도 규모를 이용한 바람장의 균질성 평가 및 영향요소 분석 (The assessment of the Spatial Variation of the Wind Field using the Meso-velocity Scale and its Contributing Factors)

  • 이성은;신선희;하경자
    • 대기
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    • 제20권3호
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    • pp.343-353
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    • 2010
  • A regional wind network with complex surface conditions must be designed with sufficient space and time resolution to resolve the local circulations. In this study, the spatial variations of the wind field observed in the Seoul and Jeju regional networks were evaluated in terms of annual, seasons, and months to assess the spatial homogeneity of wind fields within the regional networks. The coherency of the wind field as a function of separation distance between stations indicated that significant coherency was sometimes not captured by the network, as inferred by low correlations between adjacent stations. A meso-velocity scale was defined in terms of the spatial variability of the wind within the network. This problem is predictably most significant with weak winds, dull prevailing wind, clear skies and significant topography. The relatively small correlations between stations imply that the wind at a given point cannot be estimated by interpolating winds from the nearest stations. For the Seoul and Jeju regional network, the meso-velocity scale has typically a same order of magnitude as the speed of the network averaged wind, revealing the large spatial variability of the Jeju network station imply topography and weather. Significant scatter in the relationship between spatial variability of the wind field and the wind speed is thought to be related to thermally-generated flows. The magnitude of the mesovelocity scale was significantly different along separation distance between stations, wind speed, intensity of prevailing wind, clear and cloudy conditions, topography. Resultant wind vectors indicate much different flow patterns along condition of contributing factors. As a result, the careful considerations on contributing factors such as prevailing wind in season, weather, and complex surface conditions with topography and land/sea contrast are required to assess the spatial variations of wind field on a regional network. The results in the spatial variation from the mesovelocity scale are useful to represent the characteristics of regional wind speed including lower surface conditions over the grid scale of large scale atmospheric model.

북동 기류와 관련된 영동해안 지역의 대설 사례에 대한 WRF수치모의 연구 (A Numerical Simulation Study Using WRF of a Heavy Snowfall Event in the Yeongdong Coastal Area in Relation to the Northeasterly)

  • 이재규;김유진
    • 대기
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    • 제18권4호
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    • pp.339-354
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    • 2008
  • A numerical simulation of a heavy snowfall event that occurred 13 January 2008 along the Yeongdong coastal area, was performed using WRF (Weather Research and Forecasting) in order to reveal mesoscale structures and to construct a conceptual model showing the meteorological background that caused the large difference in snowfall amounts between the Yeongdong mountain area and the Yeongdong coastal area. The simulation results matched well with various observations such as corresponding 12h-accumulated observed precipitation, surface wind obscrvation, radar echoes, and satellite infrared images. The simulation and the observations showed that the scale of the event was of meso - $\beta$ and meso - $\gamma$ scale. The simulation represented well the mesoscale process causing the large difference in snowfall amounts in the two areas. First, wind flow was kept, to a certain extent, from crossing the mountains due to the blocking effect of the low Froude number (~1). The northeast flow over the adjaccnt sea tumcd northwest as it approachcd the mountains, where it was trapped, allowing so-called cold air damming. Second, a strong convergence area formed where the cold northwest flow along the Yeongdong coastal area and the relatively warm and moist northeast flow advecting toward the coast met, supporting the fonllation of a coastal front. Thus, the vertical motion was strongest over the front located near the coast, leading to the heavy snowfall there rather than in the remote mountain area.