• Title/Summary/Keyword: Vertical Circulation

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Estimation of Vertical Profiles and Total Amount of Ozone Using Two-Dimensional Photochemical Transfer Model During the Period of 1995-1996 at Pohang (2차원 광화학수송모델을 이용한 포항지역의 1995-1996년 기간동안 오존의 연직 프로파일 및 전량 추정)

  • Moon, Yun-Seob
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.3
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    • pp.271-285
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    • 2006
  • A two-dimensional photochemical transport model (2D PTM) is simulated to describe the transport and chemical reaction of ozone related to aerosols in the troposphere and stratosphere. The vertical profiles and total amounts of ozone, which are advected by both residual Eulerian circulation and the adiabatic circulation under certain circumstance, have been compared with the observation data such as ozonesondes, Brewer spectrometer, the Upper Atmosphere Research Satellite (UARS), and the Total Ozone Mapping Spectrophotometer (TOMS). As a result, we find that the observed distribution of ozone Is adequately reproduced in the model at middle and high latitude in the Northern Hemisphere as well as at Phang ($36^{\circ}\;02'N,\;129^{\circ}\;23'E$) in South Korea. In particular, the 2D PTM is well simulated in the ozone decrease due to the Pinatubo volcanic eruption in 1991. However, ozone mixing ratio are more underestimated than those of UARS and ozonesondes, because are very sensitive to the latitude of transport across the tropopause associated with both Rummukainen errors and off-line model. Relative mean bias errors and relative root mean square errors of ozone calculations using the 2D PTM are shown within${\pm}10%$, respectively.

Vertical Distribution of Phytoplankton in the Paldang Dam Reservior (팔당댐 담수수역 식물플랑크톤의 수직분포)

  • Lee, Kyung
    • Journal of Plant Biology
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    • v.29 no.2
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    • pp.117-127
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    • 1986
  • Phytoplankton community was investigated at the Paldang Dam Reservoir in the Mid-Han River by it's depth, in spring and summer known as the period of phytoplankton's blooming. It was only in summer that phytoplankton bloomed at the investigated area. 128 kinds of phytoplankton were identified and of them, diatoms were abundunt in spring but cyanophyta and chlorophyta were in summer. Because some species with high pollution index were observed in summer, it could be proved that the investigated area was polluted especially in summer. In spring shown the circulation period by vertical distribution pattern of chlorophyll-a and isothermal distribution pattern of water temperature, maximum value of phytoplankton standing crops appeared at the upper layer, except for surface layer. In summer shown the circulation period after the stagnation period by vertical distribution pattern of chlorophyll-a and immediate destruction after stratification of water temperature, maximum value of phytoplankton standing crops appeared at the lower layer. the layer at which the maximum value of chlorophyll-a appeared also accorded with that of phytoplankton standing crops. So, it could be approved that there existed a close relationship among phytoplankton standing crops, chlorophyll-a, and water temperature.

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The Effect of Surface and Vertical Observation Data Assimilation on the Horizontal and Vertical Flow Fields Depending on the Upper Wind Conditions (종관 특성에 따른 지상 및 연직 관측자료 동화가 수평 및 연직 확산장에 미치는 영향)

  • Choi, Hyun-Jung;Lee, Hwa-Woon;Kim, Min-Jung
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.2
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    • pp.177-189
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    • 2010
  • In order to incorporate correctly the large or local scale circulation in an atmospheric model, a nudging term is introduced into the equation of motion. The MM5 model was used to assess the meteorological values differences in each case, during ozone episode days in Gwangyang bay. The main objective of this study is to investigate the effect of horizontal and vertical flow fields according to the surface and vertical observation data assimilation by upper wind conditions. Therefore, we carried out several numerical experiments with various parameterization methods for nudging coefficient considering the upper wind conditions (synoptic or asynoptic condition). Nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, therefore appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. Obviously, under the weak synoptic wind, there was apparent advantage associated with nudging coefficient by the regional difference. The accuracy for the prediction of the meteorological values has been improved by applying the appropriate PBL (Planetary Boundary Layer) limitation of circulation.

A Study on the Type and Characteristics of the Spatial Structure in Major Space of Museums (박물관 대공간의 공간구조 형식과 특성에 관한 연구)

  • Park, Se-Min;Jung, Sung-Wook
    • Korean Institute of Interior Design Journal
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    • v.17 no.6
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    • pp.178-187
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    • 2008
  • This study aims to analyze general features and forms of spatial structure of major space in museums and for the scope of this study, set up major space and the surrounding areas structured around major space and for the target of analysis, selected 10 museums of overseas examples from 19th century to 2006. And this study on focus, on the circulation structure and visual structure will be analyzed in qualitative method by focusing on the floor plan and section structures; deepening process of analysis, visual structure will turn into numerical value to analyze the spatial structure of the major space. The results of this study are as follow. First, vertical elements should be critically considered in a circulation plan for functional performance of dimensional circulation distribution in a major space. Second, a plan by location of vertical and horizontal moving elements related to a major space affects a circulation relation more than a connection type between a major space and an exhibition area. Third, it could be categorized into 4 types by considering the features of spatial structure followed by connecting relationship between areas. Fourth, comparable figures were drawn out among large space and surrounding areas but it couldn't draw out types.

Effect of the Wind on the Pollutant Transport in Masan Bay (마산만의 오염물질 수송에 미치는 바람 효과)

  • Kim, Jong-Hwa;Lee, Mun-Ok;Gang, Ju-Bok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.4
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    • pp.385-397
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    • 1992
  • Current measurements at 3 sections and numerical experiments were carried out in Masan Bay to understand the effect of the wind on the residual currents and pollutant transport. The vertical distribution of horizontal velocities were directly affected by the wind at the depths of 1m and 2m beneath the sea surface. Analysis of the velocity data suggested that changes in the vertical gravitational circulation contributed to the net circulation. The net transport of water through the northern part of the bay was observed to be landward, with wind-induced transport of about 100m super(3)/s. Hence, wind is concluded to be the dominant mechanism driving the net circulation in the northern area of Masan Bay. Numerical experiments are shown that when S wind with 5m/s blew, northern area of the bay was generated the horizontal circulation of clockwise and local gyre. On the contrary of those, N wind made her to the anti-clockwise. In the case of no wind, the tidal residual current(constant flow) is very small or neglected except the bay-mouth. The inflow or outflow pattern of the mouth is considered as the flows generated by tidal residual current only. The distance of wind-induced transport of pollutant was as long as 2 times of no wind during the one tidal period.

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A Conceptual Two-Layer Model of Thermohaline Circulation in a Pie-Shaped $\beta$-Plane Basin

  • Park, Young-Gyu
    • Journal of the korean society of oceanography
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    • v.38 no.1
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    • pp.11-16
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    • 2003
  • The three dimensional structure of thermohaline circulation in a D-plane is investigated using a conceptual two layer model and a scaling argument. In this simple model, the water mass formation region is excluded. The upper layer represents the oceans above the main thermocline. The lower layer represents the deep ocean below the thermocline and is much thicker than the upper layer. In each layer, geostrophy and the linear vorticity balance are assumed. The cross interfacial velocity that compensates for the deep water mass formation balances downward heat diffusion from the top. From the above relations, we can determine the thickness of the upper layer, which is the same as thermocline depth. The results we get is basically the same as that we get for an f-plane ocean or the classical thermocline theory. Mass budget using the velocity scales from the scaling argument shows that western boundary and interior transports are much larger than the net meridional transport. Therefore in the thermohaline circulation, horizontal circulation is much stronger than the vertical circulation occuring on a meridional plane.

A Numerical Experiments on the Atmospheric Circulation over a Complex terrain around Coastal Area. Part I : A Verification of Proprietyh of Local Circulation Model Using the Linear Theory (연안부근 복잡지형의 대기유동장 수치실험 I -선형이론을 이용한 국지순환모형의 타당성 검토-)

  • 이화운;김유근;정우식
    • Journal of Environmental Science International
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    • v.8 no.5
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    • pp.555-558
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    • 1999
  • A sea/land breeze circulation system and a regional scale circulation system are formed at a region which has complex terrain around coastal area and affect to the dispersion and advection of air pollutants. Therefore, it is important that atmospheric circulation model should be well designed for the simulation of regional dispersion of air pollutants. For this, Local Circulation Model, LCM which has an ability of high resolution is used. To verify the propriety of a LCM, we compared the simulation result of LCM with an exact solution of a linear theory over a simple topography. Since they presented almost the same value and pattern of a vertical velocity at the level of 1 km, we had a reliance of a LCM. For the prediction of dispersion and advection of air pollutants, the wind filed should be calculated with high accuracy. A numerical simulation using LCM will provide more accurate results over a complex terrain around coastal area.

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A Study of Vertical Circulation System in General Hospitals by Using Space Syntax (공간구문론을 이용한 종합병원 수직동선체계 연구)

  • Lee, Hyunjin;Park, Jaseung
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.19 no.4
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    • pp.47-60
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    • 2013
  • Purpose: This study examines construction core plans for the users of vertical-typed general hospitals to effectivly use the flow line. Methods: The study sampled representative 9 hospitals, calculated the depth value through Convex Map of Space Syntax and Justified Graph according to the determination of form of construction cire, and analyzed its functional connectivity. Results: The analysis of the connectivity between operation core part and emergency part of core space with high importance in the hospitals showed that the types of hospital and hospital have the lowest depth value in the spatial phase diagram, where central treatment part and outpatient part are arranged well vertically. Elevators for patients at these hospitals are close to operation and emergency parts actually separated from the elevators for passengers. For shortening of flow line of patients and private movement environment, however, it is desirable to arrange the elevators for patients to be adjacent to the operation parts and to arrange the emergent patient entrances more effectively to separate them from the flow line of visitors and guardians. Implications: Consideration should be taken into account for the effective flow line design. This study hopefully may serve as a stepping stone for the standard design of horizontal/vertical flow line.

Evaluation of the Annual Performance of the Direct Expansion Vertical Closed-Loop Ground Source Heat Pump (직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가)

  • Kim, Min-Sung;Woo, Joung-Son;Baik, Young-Jin;Jang, Jea-Chul;Kim, Ji-Young;Ra, Ho-Sang
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.534-542
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    • 2012
  • Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

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Annual Performance Evaluation of Direct Expansion Vertical Closed-Loop Ground Source Heat Pump for Residential Application (주거용 직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가)

  • Kim, Min-Sung;Baik, Young-Jin;Ra, Ho-Sang
    • Journal of the Korean Solar Energy Society
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    • v.32 no.3
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    • pp.114-122
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    • 2012
  • Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.