• Journal of Ecology and Environment
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• v.47 no.2
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.163-168
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• 2005

Attenuation in vegetation is important, for both terrestrial and earth-space systems. However, the wide range of conditions and types of foliage makes it difficult to develop a generalized prediction procedure. Currently, there is also a lack of suitably prediction model and measured experimental data for vegetation loss. So in this paper, vegetation loss data for four different tree-species, including Dawn-redwood tree, Plane tree, Pine tree and Fir tree are obtained by measurement in the frequency range of 1.0 $\sim$ 6.0 GHz. The through or scattered component is calculated using a model based upon the theory of RET(Radiative Energy Transfer) and RET modeling parameters are extracted from the measured data.

• Journal of KIBIM
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• v.4 no.2
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• pp.25-32
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• 2014

Today, there is a growing need of environment-friendly buildings, so-called 'green', facilities, and energy saving buildings to decrease environmental pollutants released into cities by construction activities. Green-Building Information Modeling (Green-BIM) is a purpose-built solution which supports to forecast energy consumption of 3-D model of a building by augmenting its primary 3-D measurements (width, height and depth) with many more dimensions (e.g. time, costs, social impacts and environmental consequences) throughout a series of sequential phases in the lifecycle of a building. The current study was carried out in order to integrate vegetation systems (particularly green roof and green wall systems) and investigate thermal performance of the new Sainsbury's building which will be built on Melton road, Leicester, United Kingdom. Within this scope, a 3-D building model of the news Sainsbury's building was first developed in $Autodesk^{(R)}$ $Revit^{(R)}$ and this model was then simulated in $Autodesk^{(R)}$ $Ecotect^{(R)}$once weather data of the construction site was obtained from $Autodesk^{(R)}$ Green Building $Studio^{(R)}$. This study primarily analyzed data from (1) solar radiation, (2) heat gains and losses, and (3) heating and cooling loads simulation to evaluate thermal performance of the building integrated with vegetation system or conventionally available envelops. The results showed that building integrated vegetation system can potentially reduce internal solar gains on the building rooftops by creating a 'bioshade'. Heat gains and losses through roofs and walls were markedly diminished by offering greater insulation on the building. Annual energy loads for heating and cooling were significantly reduced by vegetation more significantly through the green roof system in comparison to green wall system.

• Journal of Environmental Science International
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• v.3 no.1
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• pp.17-29
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• 1994

An one dimensional atmosphere-vegetation interaction model is developed to discuss of the effect of vegetation on heat flux in mesoscale planetary boundary layer. The canopy model was a coupled system of three balance equations of energy, moisture at ground surface and energy state of canopy with three independent variables of $T_f$(foliage temperature), $T_g$(ground temperature) and $q_g$(ground specific humidity). The model was verified by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HYPEX-MOBHLY experiment. As the result, both vegetation and soil characteristics can be emphasized as an important factor iii the analysis of heat flux in the boundary layer. From the numerical experiments, following heat flux characteristics are clearly founded simulation. The larger shielding factor(vegetation) increase of $T_f$ while decrease $T_g$. because vegetation cut solar radiation to ground. Vegetation, the increase of roughness and resistance, increase of sensible heat flux in foliage while decrease the latent heat flux in the foliage.

• Water Engineering Research
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• v.6 no.3
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• pp.101-112
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• 2005

This paper presents the state of the art of the CFD applications to vegetated open-channel flows. First, important aspects of the physics of vegetated flows found through the laboratory experiments are briefly reviewed. Then, previous CFD applications to one-dimensional vertical structure, partly-vegetated flows, compound open-channel flows with floodplain vegetation, and fully three-dimensional numerical simulations are reviewed. Finally, topics for further researches such as relationship between the resistance and flexural rigidity, additional drag due to foliages, and melting the experience of CFD with the depth-averaged modeling, are suggested.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.449-453
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• 2008

This research focused on analyzing and comparing between the results of hydraulic physical modeling and the results of numerical modeling of Grass Concrete which is newly developed in-situ block system. The physical model was built as a scale of 1:50 by Froude similitude measuring the water levels and the water velocities for before and after vegetation and the effects were analyzed after reviewing the results. In consequence, the water velocities were observed to decrease meanly 19.1%, and the water depth were determined to increase meanly 27.8% in case of the of design flood, $Q=200m^3/sec$. Moreover, the velocities were produced reduction effects of 27.2%, and the water levels were derived from addition effects of the highest 31.3% in case of the probability maximum flood(PMF), $Q=600m^3/sec$. To verifying the hydraulic physical modeling, the numerical modeling was conducted for a close examination of before and after vegetation. HEC-RAS model was for 1 dimensional numerical analysis and RMA-2 was for 2 dimensional numerical analysis. The results of the numerical simulation, under the condition of roughness coefficient calibration, shows similar results of the physical modeling. These satisfactory results show that the accomplished results of hydraulic modeling and the predicted results of numerical modeling corresponded reasonably each others.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.1
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• pp.97-110
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• 2021

Vegetation index information is an important figure that is used in many fields such as landscape architecture, urban planning, and environment. Vegetation may vary slightly in vegetation vitality depending on photosynthesis and chlorophyll content. In this study, a range of vegetation worth preserving in the Taehwa River water system was determined, and hyperspectral images of drones were acquired (August, October), and the results were presented through DVI(Normalized Defference Vegetation Index), EVI(Enhanced Vegetation Index), PRI(Photochemical Reflectance Index), ARI (Anthocyanin Reflectance Index) index analysis. In addition, field spectral data and VRS-GPS(Virtual Reference System-GPS) surveys were performed to ensure the quality and location accuracy of the spectral band. As a result of the analysis, NDVI and EVI showed low vegetation vitality in October, -0.165 and -0.085, respectively, and PRI and ARI increased to 0.011 and 7.588 in October, respectively. For general vegetation vitality, it was suggested that NDVI and EVI analysis were effectively performed, and PRI and ARI were thought to be effective in analyzing detailed characteristics of plants by spectral band. It is expected that it can be widely used for park design and landscape information modeling by using drone image information construction and vegetation information.

• Journal of Korea Water Resources Association
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• v.56 no.3
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• pp.211-224
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• 2023

In this study, a soil moisture estimation was performed using the Water Cloud Model (WCM), a backscatter model that considers vegetation based on SAR (Synthetic Aperture Radar). Sentinel-1 SAR and Sentinel-2 MSI (Multi-Spectral Instrument) images of a 40 × 50 km² area including the Yongdam Dam watershed of the Geum River were collected for this study. As vegetation descriptor of WCM, Sentinel-1 based vegetation index RVI (Radar Vegetation Index), depolarization ratio (DR), and Sentinel-2 based NDVI (Normalized Difference Vegetation Index) were used, respectively. Forward modeling of WCM was performed by 3 groups, which were divided by the characteristics between backscattering coefficient and soil moisture. The clearer the linear relationship between soil moisture and the backscattering coefficient, the higher the simulation performance. To estimate the soil moisture, the simulated backscattering coefficient was inverted. The simulation performance was proportional to the forward modeling result. The WCM simulation error showed an increasing pattern from about -12dB based on the observed backscattering coefficient.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1335-1339
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• 2004

A hydro-geomorphologic change in a sand bed channel reach and vegetation expansion by changes in the How regime is analyzed in this study. Field and aerial photo surveys, basic hydrological analysis about flow regime change due to two dams, Andong Dam and Imha Dam, on the upstream river and computer modeling are conducted. Two Dams in the study reach have obviously affected downstream channel in many ways including the bed particle coarsening, vegetation expansion on the sandbars and following river channel braiding. The phenomenon of no vegetation on the large point bar in front of Hahwe Village seems due to disturbance of the sandbar surface probably due to the cross flow in the meander reach during the flood. Another reason for no vegetation is that the sandbar on this reach has lower subsurface water lovels, as compared with the others in the up- and downstream of the reach where vegetation expanded, which would hinder vegetation from germinating and growing on the sandbar.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.87-97
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• 2008

This research focused on development and application feasibility for the coalesced continuous block system in river bank protection. Most of block systems in river bank are pre cast type and have some difficulties against high velocity flood condition or high pressure load, however, the continuous block system can be applied to flood damage recover as well as environmental vegetation block system in river bank. For the application review and analysis of hydraulic condition for this block system, hydraulic physical modeling was carried out. The physical model was built as a scale of 1:50 by Froude similitude measuring the water levels and the water velocities for vegetation application or not. In consequence, the water velocities were observed to decrease meanly 10.1%, and the water depths were to increase meanly 17.8% in case of the of design flood, $Q=200m^3/sec$. To verify the hydraulic physical modeling, the numerical modeling should be conducted for a close examination of vegetation application by one or two dimensional numerical analysis as a next study.