Evapotranspiration from a Deciduous Forest in a Complex Terrain and d Heterogeneous Farmland Under Monsoon Climate

Minseok Kang,Sungbin Park,Hyojung Kwon,Hyung Tae Choi,Young-Jean Choi,Joon Kim 한국기상학회 2009 Asia-Pacific Journal of Atmospheric Sciences Vol.45 No.2

Evapotranspiration (ET) was measured by eddy covariance method in two key ecosystems in Korea: (1) the Gwangneung site (a deciduous forest in a complex terrain located in the central north ­ part of the Korean Peninsula, GDK) and (2) the Haenam site (a heterogeneous farmland located in the west­central part of the Korean Peninsula, HFK). By using the multi­year observations (GDK: 2005~2007, HFK: 2004~2006), we quantified ET and analyzed its temporal variations and controlmechanisms based on the radiatively coupled combination equation. During the study period, the averaged annual precipitation was about 1500 ㎜ for both sites, of which 1/4 returned to the atmosphere as ET at the GDK. At the HFK site, annual ET averaged 623 ㎜, which was 41%of the annual rainfall. Both sites showed a characteristic seasonality withmid­season depressions in ET that are associated with the reduced amount of available energy during the monsoon season. The decoupling parameter (Ω*), which indicates the measure of interaction between vegetation and the atmosphere, averaged 0.37 for the GDK site and 0.50 for the HFK site during the growing season. The ET from the HFK site was equally contributed by both equilibrium ET and imposed ET, whereas the GDK site was to some extent more influenced by imposed ET (hence, air saturation deficit and surface conductance).

Development of a shot noise process based rainfall-runoff model for urban flood warning system

Kang, Minseok,Yoo, Chulsang 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.1

본 연구에서는 도시유역에서의 실시간 홍수예경보 목적으로 shot noise process 기반의 강우-유출모형을 제안하였다. 제안된 모형은 각 소유역별 첨두치, 감쇄상수 및 지체시간으로 결정되는 shot noise의 합으로 표현되며, 기존 강우-유출 모형과는 달리 각 소유역 별 유출량이 독립적으로 유역 출구에 도달하는 구조를 가지고 있다. 제안된 모형의 매개변수는 통상 경험식을 가지고 결정하는 소유역의 집중시간과 저류상수 및 관로에서의 도달시간과 저류상수를 이용하여 쉽게 결정될 수 있는 것으로 확인되었다. 본 연구에서 제안된 모형은 중동 빗물펌프장 배수유역, 구로1 빗물펌프장 배수유역, 대림2 빗물펌프장 배수유역에서 관측된 총 3개의 호우사상에 적용하여 그 성능을 평가하였다. 그 결과를 정리하면 다음과 같다. (1) 본 연구에서 제안된 shot noise process 기반 단위 응답함수는 기존 단위 응답함수와 달리 강우 지속기간에 관계없이 동일한 모양을 갖는다. (2) 제안된 모형의 특성상 강우의 시간간격이 짧을수록 수렴된 결과를 얻을 수 있다. 따라서 도시유역의 특성을 감안할 때 1분이 가장 적절한 것으로 판단된다. (3) Shot noise process 기반 1분 단위 응답함수를 실제 호우사상에 적용하여 유출해석을 수행한 결과, 모의된 유출 수문곡선과 관측 값이 매우 유사한 것으로 나타났다. 이러한 결과는 도시유역에서의 유출해석을 수행하는데 있어 제안된 유출모형이 충분한 적용성이 있다는 것을 보여준다. This study proposed a rainfall-runoff model for the purpose of real-time flood warning in urban basins. The proposed model was based on the shot noise process, which is expressed as a sum of shot noises determined independently with the peak value, decay parameter and time delay of each sub-basin. The proposed model was different from other rainfall-runoff models from the point that the runoff from each sub-basin reaches the basin outlet independently. The model parameters can be easily determined by the empirical formulas for the concentration time and storage coefficient of a basin and those of the pipe flow. The proposed model was applied to the total of three rainfall events observed at the Jungdong, Guro 1 and Daerim 2 pumping stations to evaluate its applicability. Summarizing the results is as follows. (1) The unit response function of the proposed model, different from other rainfall-runoff models, has the same shape regardless of the rainfall duration. (2) The proposed model shows a convergent shape as the calculation time interval becomes smaller. As the proposed model was proposed to be applied to urban basins, one-minute of calculation time interval would be most appropriate. (3) Application of the one-minute unit response function to the observed rainfall events showed that the simulated runoff hydrographs were very similar to those observed. This result indicates that the proposed model has a good application potential for the rainfall-runoff analysis in urban basins.

Identifying CO₂ advection on a hill slope using information flow

Kang, Minseok,Ruddell, Benjamin L.,Cho, Chunho,Chun, Junghwa,Kim, Joon Elsevier 2017 Agricultural and forest meteorology Vol.232 No.-

<P><B>Abstract</B></P> <P>In hilly terrain affected by drainage flow, the horizontal advection of CO<SUB>2</SUB> makes it difficult to accurately observe the net ecosystem exchange of CO<SUB>2</SUB> by the eddy covariance technique. Downslope drainage can result in an overestimation of respiration at the bottom of a hill slope and an underestimation at the top, resulting in discrepancies among different flux corrections using filters based on the friction velocity, light response curve, and timing of advection. Vertical profiles of the CO<SUB>2</SUB> concentration from the ground to above the canopy were measured along with above-canopy EC flux measurements at the top and bottom of a hill slope at the Gwangneung KoFlux sites from 2008 to 2010. To infer the timing, direction, temporal scale, and structure of CO<SUB>2</SUB> advection from uphill to downhill, we constructed an information flow dynamical process network (DPN) based on the observed multi-level CO<SUB>2</SUB> concentrations. A site-specific quality control filter was developed to eliminate data strongly affected by CO<SUB>2</SUB> advection, which identifies the observations when strong downslope information flow exists in the DPN. This site-specific filter considerably reduced the discrepancies among different traditional flux corrections. This research provides a method for the general characterization of advection using information flow, and application of the method as a site-specific filter for eddy covariance observations in hilly and complex terrain.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Drainage flow affects the eddy covariance CO<SUB>2</SUB> fluxes on the forest hill slope of the Gwangneung KoFlux sites. </LI> <LI> The CO<SUB>2</SUB> drainage is identified using an information flow dynamical process network (DPN). </LI> <LI> Based on the DPN, a site-specific filter was developed to eliminate the drainage-affected data. </LI> <LI> An information flow filter reduces discrepancies among the different nighttime flux corrections. </LI> </UL> </P>

New gap-filling and partitioning technique for H₂O eddy fluxes measured over forests

Kang, Minseok,Kim, Joon,Malla Thakuri, Bindu,Chun, Junghwa,Cho, Chunho Copernicus GmbH 2018 Biogeosciences Vol.15 No.2

<P><p><strong>Abstract.</strong> The continuous measurement of H<span class='inline-formula'>₂</span>O fluxes using the eddy covariance (EC) technique is still challenging for forests because of large amounts of wet canopy evaporation (<span class='inline-formula'><i>E</i>_WC)</span>, which occur during and following rain events when the EC systems rarely work correctly. We propose a new gap-filling and partitioning technique for the H<span class='inline-formula'>₂</span>O fluxes: a model-statistics hybrid (MSH) method. It enables the recovery of the missing <span class='inline-formula'><i>E</i>_WC</span> in the traditional gap-filling method and the partitioning of the evapotranspiration (ET) into transpiration and (wet canopy) evaporation. We tested and validated the new method using the data sets from two flux towers, which are located at forests in hilly and complex terrains. The MSH reasonably recovered the missing <span class='inline-formula'><i>E</i>_WC</span> of 16-41<span class='thinspace'></span>mm<span class='thinspace'></span>yr<span class='inline-formula'>⁻¹</span> and separated it from the ET (14-23<span class='thinspace'></span>% of the annual ET). Additionally, we illustrated certain advantages of the proposed technique which enable us to understand better how ET responds to environmental changes and how the water cycle is connected to the carbon cycle in a forest ecosystem.</p> </P>

Effects of European Identity Upon Refugee protection: The case of 6 Western European countries

Minseok Kang 미래사회통합연구센터 2021 Journal of Conflict and Integration Vol.5 No.1

This study analyzes the effect of European identity on refugee protection in the 6 Western European countries from 2016 to 2019, especially focusing on the inclusive/exclusive mechanism of European identity. It is confirmed that the countries with higher European identity tend to record higher level of refugee recognition rate and higher refugee protection awareness, while the countries with lower European identity have tendency of lower refugee recognition rate and lower refugee protection awareness. Accordingly, European identity could be regarded as inclusive and integrative identity based on the normative values that the European Union have emphasized in the process of European integration.

Ship block assembly sequence planning considering productivity and welding deformation

Minseok Kang,Jeongyeon Seo,Hyun Chung 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

Momentary level of slow default mode network activity is associated with distinct propagation and connectivity patterns in the anesthetized mouse cortex

Kang, Minseok,Lee, Young-Beom,Gohel, Bakul,Yoo, Kwangsun,Lee, Peter,Chung, Jinyong,Jeong, Yong American Physiological Society 2018 journal of neurophysiology Vol.119 No.2

Ship block assembly sequence planning considering productivity and welding deformation

Kang, Minseok,Seo, Jeongyeon,Chung, Hyun The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

A new classification rule of hydrological soil groups of Jeju Island: Application to representative basins and evaluation of previous studies

Kang Minseok,Lee Youngju,Park Changyeol,Yoo Chulsang 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.12

본 연구에서는 Lee et al.(2018)의 연구에서 제시한 새로운 수문학적 토양군 분류 방법을 제주도의 3개의 하천유역(중문천, 천미천, 한천)에 적용하고 그 적용성을 평가하였다. 적용의 결과로서 이들 세 유역의 CN 값이 산정되었으며, 이 값은 기존의 세 가지 방법론을 적용한 결과와 비교하였다. 또한 제주도에서의 침투, 강우-유출 해석 등에 사용되는 수문학적 토양군 분류와 관련된 선행 연구들을 검토하여 선택된 방법론에 따라 수문학적 토양 군 분류 결과가 어떻게 다른지를 평가하였다. 그 결과를 정리하면 다음과 같다. (1) 수문학적 토양군 분류 방법에 따른 제주도 대표 유역의 수문학적 토양군 분류 결과를 비교한 결과, Lee et al.(2018)의 토양군 분류 방법을 적용하는 경우에는 B군이 크게 나타났다. 이는 Hu and Jung(1987)의 분 류 방법을 적용하는 경우에서는 C군과 D군이, Jung et al.(1995)의 분류 방법을 적용하는 경우에서 A군과 C군, 마지막으로 RDA(2007)의 분류 방 법을 적용하는 경우에서는 D군이 상대적으로 크게 나타나는 결과와 비교된다. (2) Lee et al.(2018)의 수문학적 토양군 분류 방법을 제주도의 3개 대표 유역에 적용한 결과, 3개 유역 모두 기존 방법에 비해 가장 작은 CN 값이 추정되었다. 마지막으로 (3) 제주도에서의 강우-유출과 관련된 연구를 검토한 결과, 제주도 유역의 CN 값은 기존 방법에 의해 추정된 것에 비해 작을 가능성이 크고, 또한 초기 손실은 0.2S 이상의 큰 값을 가질 것으로 판단되었다. This study evaluates the applicability of the classification rule of hydrological soil group proposed by Lee et al. (2018) with its application to three river basins (Jungmuncheon, Cheonmicheon, and Hancheon) in Jeju Island. The CN values are estimated as results of this application to these three basins, which is then compared with those estimated by applying the conventional three methods. Additionally, previous studies related with the classification of soil groups of Jesu Island, such as the infiltration and rainfall-runoff analysis, are reviewed to evaluate how the resulting hydrological soil groups vary depending on the adopted classification method.. Summarizing the results is as follows. (1) Comparison result of the hydrological soil groups of Jeju Island with respect to the classification method shows that the soil group B is dominant in the application of Lee et al. (2018). However, it is hydrological soil groups C and D in the application of Hu and Jung (1987), hydrological soil groups A and C in the application of Jung et al. (1995), and hydrological soil group D in the application of RDA (2007). (2) In all the applications of Lee et al. (2018) to three selected river basins in Jeju Island, the CN valuse are found to be smaller than those by other conventional three methods.. Lastly, (3) The evaluation results of previous studies related with the classification of hydrological soil groups analysis in Jeju Island shows that the CN value in the Jeju Island may be smaller than those estimated by conventional three methods, also the initial loss higher than 0.2S.

An Empirical Investigation of Student Acceptance of Synchronous E-Learning in an Online University

Kang, Minseok,Shin, Won sug SAGE Publications 2015 Journal of educational computing research Vol.52 No.4