• Title/Summary/Keyword: GIS Simulation

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Analysis of the Thermal Environment around an Urban Green Area in Seoul, Korea Using Climate Analysis Seoul (CAS) (Climate Analysis Seoul (CAS)를 이용한 서울 도심 녹지 주변의 열 환경 분석)

  • Lee, Jisu;Lee, Young-Gon;Kim, Baek-Jo
    • Atmosphere
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    • v.26 no.3
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    • pp.413-421
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    • 2016
  • Climate Analysis Seoul (CAS) which provides gridded data relevant for thermal assessment was applied to one of the urban green areas, the Seonjeongneung, in Seoul, Korea. The thermal environment in the Seonjeongneung was evaluated from the CAS simulation for the five heat-wave issued cases during the last five years (2011~2015). The CAS has been improved continuously since it was developed. An updated version with a higher resolution of the CAS simulation domain and an addition of the vegetation information was used in this study. The influence of vegetation in the Seonjeongneung is estimated through the amount of the cold air generation ($Q_{ca}$) and air temperature deviation at each grid points, which are calculated by incorporating Geographic Information System (GIS) analysis on the simulation domain and meteorological analysis with the METeorology and atmospheric PHOtochemistry mesoscale MODel (MetPhoMod) in the CAS. The average amount of the cold air generation ($Q_{ca}$) at the Seonjeongneung is about $25.5m^3m^{-2}h^{-1}$ for the whole cases, and this value is similar to the ones in a forest or a well-wooded region. The average value of the total air temperature deviation (TD) is $-2.54^{\circ}C$ at the Seonjeongneung for the five cases. However, this cooling effect of the urban green area disappeared when the region is replaced by high-rise buildings in the CAS simulation. The $Q_{ca}$ drastically decreases to about $1.1m^3m^{-2}h^{-1}$ and the average TD shows an increase of $1.14^{\circ}C$ for the same events. This result shows that the vegetation in the Seonjeongneung supposes to keep down temperature during the heat-wave issued day and the average cooling effect of the green region is $3.68^{\circ}C$ quantitatively from the TD difference of the two simulations. The cooling effect represented with the TD difference is larger than $0.3^{\circ}C$ within 200 m distance from the boundary of the Seonjeongneung. Further improvements of the thermodynamical and advection processes above the model surface are required to consider more accurate assessment of the cooling effect for the urban green area.

Analysis of Suspended Solids Reduction by Vegetative Filter Strip for Cultivated Area Using Web GIS-Based VFSMOD (VFSMOD를 이용한 경작지의 고형물질 유출 저감효과)

  • Ahn, Jae Hwan;Yun, Sang Leen;Kim, Seog Ku;Park, Youn Shik;Lim, Kyoung Jae
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.12
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    • pp.792-800
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    • 2012
  • The study was performed to simulate the reduction efficiency of suspended solids (SS) for cultivated land located at riverine area at the Namhan River and the Bukhan River watershed sites (site A, B, C) under the rainfall conditions using HUFF & SCS UH-based VFS Design module of Web GIS-based VFSMOD System. The study indicates that the field 5% sloped, located at Bukhan River watershed (site A), requires at least 0.5 m width of Vegetative Filter Strip (VFS) to reduce 70% of SS while the field 10% sloped requires the at least 1.0~1.5 m width of VFS to reduce 70% SS, under the condition 106.2 mm of rainfall event and bell pepper or corn of crops. Against the conditions 95.1 mm of rainfall event and sweet potato or soy bean of crops, the field 5% sloped, located at Namhan River watershed (site B) requires at least 0.5 m width of VFS to reduce 70% of SS while the field 10% sloped requires at least 1.0 m width of VFS to reduce 50% SS. The crops sweet potato and soy bean are cultivated in the site C, located at Namhan River watershed, 1 m of VFS is capable of 64.0% and 62.0% of SS reduction against 102.6 mm and 151.2 mm rainfall conditions respectively, for the 5% sloped field. The result supports that VFS is one of most potential methods to reduce SS from cultivated area, which is environment-friendly hydrologic structure. The VFS design, however, needs to be simulated before its installation in the field, the simulation needs to consider not only various characteristics of the field but also different conditions affecting the VFS, using a model capable to consider a lot of factors.

Applicability evaluation of GIS-based erosion models for post-fire small watershed in the wildland-urban interface (WUI 산불 소유역에 대한 GIS 기반 침식모형의 적용성 평가)

  • Shin, Seung Sook;Ahn, Seunghyo;Song, Jinuk;Chae, Guk Seok;Park, Sang Deog
    • Journal of Korea Water Resources Association
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    • v.57 no.6
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    • pp.421-435
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    • 2024
  • In April 2023, a wildfire broke out in Gangneung located in the east coast region due to the influence of the Yanggang-local wind. In this study, GIS-based RUSLE(Revised Universal Soil Loss Equation) and SEMMA (Soil Erosion Model for Mountain Areas) were used to evaluate the erosion rate due to vegetation recovery in a small watershed of the Gangneung WUI(Wildland-Urban Interface) fire. The small watershed of WUI fire has a low altitude range of 10-30 m and the average slope of 10.0±7.4° which corresponds to a gentle slope. The soil texture was loamy sand with a high organic content and the deep soil depth. As herbaceous layer regenerated profusely in the gully after the wildfire, the NDVI (Normalized Difference Vegetation Index) reached a maximum of 0.55. Simulation results of erosion rates showed that RUSLE ranged from 0.07-94.9 t/ha/storm and SEMMA ranged from 0.24-83.6 t/ha/storm. RUSLE overestimated the average erosion rate by 1.19-1.48 times compared to SEMMA. The erosion rates were estimated to be high in the middle slope where burned pine trees were widely distributed and the slope was steep and to be relatively low in the hollow below the gully where herbaceous layer recovers rapidly. SEMMA showed a rapid increase in erosion sensitivity under at certain vegetation covers with NDVI below 0.25 (Ic = 0.35) on post-fire hillslopes. Gentle slopes with high organic content and rapid recovery of natural vegetation had relatively low erosion rate compared to steep slopes. As subsequent infrastructure and human damages due to sediment disaster by heavy rain is anticipated in WUI fire areas, the research results may be used as basic data for targeted management and decision making on the implementation of emergency treatment after the wildfire.

Current Status of the 3-D Spatial Information Systems for Local Government and Their Revitalization Plan (지자체 3차원 공간정보시스템의 현황 및 활성화 방향에 관한 연구)

  • Yun, Jeong-Mi;Kim, Tae-Woo;Suh, Yong-Cheol
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.4
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    • pp.22-32
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    • 2011
  • The 3-D spatial information systems are effective for systematical urban management and civil administration. They have more visibility than the 2-D spatial information systems with height information. However, the 3-D spatial information systems for local government were developed by central government's master plan of national spatial informatization. It means that the systems are biased toward the 3-D viewing as the visibility like a 3-D display and simulation, without reflected distinct characteristics of the local society. In order to utilize municipalities'3-D spatial information systems efficiently, above all, we have to understand the current status of municipalities'3-D spatial information systems and then have to search the ways applying actively. Therefore, we reviewed the current 3-D spatial information systems and discussed the development directions with central government's national spatial informatization master plans in order to perform properly on the 3-D spatial information system's excellent functions. We analyzed each system characteristics based on the applicability to civil administration which has the potential usage of spatial information. Additionally we suggested the development directions of 3-D spatial information systems for municipalities'through reviewing which civil administrative tasks 3-D spatial information can be applied. The consideration was based on the user demand research of the 3-D spatial information system in Chungcheongnam-do.

Implementation of Saemangeum Coastal Environmental Information System Using GIS (지리정보시스템을 이용한 새만금 해양환경정보시스템 구축)

  • Kim, Jin-Ah;Kim, Chang-Sik;Park, Jin-Ah
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.4
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    • pp.128-136
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    • 2011
  • To monitor and predict the change of coastal environment according to the construction of Saemangeum sea dyke and the development of land reclamation, we have done real-time and periodic ocean observation and numerical simulation since 2002. Saemangeum coastal environmental data can be largely classified to marine meteorology, ocean physics and circulation, water quality, marine geology and marine ecosystem and each part of data has been generated continuously and accumulated over about 10 years. The collected coastal environmental data are huge amounts of heterogeneous dataset and have some characteristics of multi-dimension, multivariate and spatio-temporal distribution. Thus the implementation of information system possible to data collection, processing, management and service is necessary. In this study, through the implementation of Saemangeum coastal environmental information system using geographic information system, it enables the integral data collection and management and the data querying and analysis of enormous and high-complexity data through the design of intuitive and effective web user interface and scientific data visualization using statistical graphs and thematic cartography. Furthermore, through the quantitative analysis of trend changed over long-term by the geo-spatial analysis with geo- processing, it's being used as a tool for provide a scientific basis for sustainable development and decision support in Saemangeum coast. Moreover, for the effective web-based information service, multi-level map cache, multi-layer architecture and geospatial database were implemented together.

Performance Evaluation of the Runoff Reduction with Permeable Pavements using the SWMM Model (SWMM 분석을 통한 투수성 포장의 유출 저감 특성 평가)

  • Lin, Wuguang;Ryu, SungWoo;Park, Dae Geun;Lee, Jaehoon;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.17 no.4
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    • pp.11-18
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    • 2015
  • PURPOSES: This study aims to evaluate the runoff reduction with permeable pavements using the SWMM analysis. METHODS: In this study, simulations were carried out using two different models, simple and complex, to evaluate the runoff reduction when an impermeable pavement is replaced with a permeable pavement. In the simple model, the target area for the analysis was grouped into four areas by the land use characteristics, using the statistical database. In the complex model, simulation was performed based on the data on the sewer and road network configuration of Yongsan-Gu Bogwang-Dong in Seoul, using the ArcGIS software. A scenario was created to investigate the hydro-performance of the permeable pavement based on the return period, runoff coefficient, and the area of permeable pavement that could be laid within one hour after rainfall. RESULTS : The simple modeling analysis results showed that, when an impervious pavement is replaced with a permeable pavement, the peak discharge reduced from $16.7m^3/s$ to $10.4m^3/s$. This represents a reduction of approximately 37.6%. The peak discharge from the whole basin showed a reduction of approximately 11.0%, and the quantity decreased from $52.9m^3/s$ to $47.2m^3/s$. The total flowoff reduced from $43,261m^3$ to $38,551m^3$, i.e., by approximately 10.9%. In the complex model, performed using the ArcGIS interpretation with fewer permeable pavements applicable, the return period and the runoff coefficient increased, and the total flowoff and peak discharge also increased. When the return period was set to 20 years, and a runoff coefficient of 0.05 was applied to all the roads, the total outflow reduced by $5195.7m^3$, and the ratio reduced to 11.7%. When the return period was increased from 20 years to 30 and 100 years, the total outflow reduction decreased from 11.7% to 8.0% and 5.1%, respectively. When a runoff coefficient of 0.5 was applied to all the roads under the return period of 20 years, the total outflow reduction was 10.8%; when the return period was increased to 30 and 100 years, the total outflow reduction decreased to 6.5% and 2.9%, respectively. However, unlike in the simple model, for all the cases in the complex model, the peak discharge reductions were less than 1%. CONCLUSIONS : Being one of the techniques for water circulation and runoff reduction, a high reduction for the small return period rainfall event of penetration was obtained by applying permeable pavements instead of impermeable pavement. With the SWMM analysis results, it was proved that changing to permeable pavement is one of the ways to effectively provide water circulation to various green infrastructure projects, and for stormwater management in urban watersheds.

A Study on the Change of Urban Land Use According to the Change of Transportation Accessibility (교통 접근성 변동에 따른 도시 토지이용 변화에 관한 연구)

  • Won, Seok Hwan;Hwang, Chul-sue
    • Journal of Cadastre & Land InformatiX
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    • v.47 no.1
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    • pp.127-142
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    • 2017
  • The purpose of this study is to examine the status of urbanization of Namyangju-Si from 2001 till 2008, analyze the correlation of the change of surrounding land use according to the change of accessibility and analyze the correlation of the change of land use. Based on the result from correlation analysis, I simulated from the view point of interactions between agents of land use and transportation accessibility by using MAS. I tried to forecast, based on space, the change of surrounding land use caused by the change of accessibility. I conducted landscape analysis by using a land registration map. Also, I conducted GIS analysis statistical analysis simulation analysis of traffic data, land use data in order to analyze the correlation of the change of surrounding land use according to the change of accessibility. I could find out a certain pattern that new roads and railroads causes the within 500m adjacent land to change into urban land use, which led me to construct a system through which land use changing phenomenon can be expected according to the change of accessibility. It is expected that it can make the best use of selecting the location where new transportation facilities are constructed.

Effect of a Hydrologic Similarity Unit and Storm Sewer Resolution on the SWMM Model Performance (수문학적 유사단위와 우수관망의 공간정밀도가 SWMM모형 성과에 미치는 영향)

  • Ha, Sung-Ryong;Lee, Kang-Won
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.2
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    • pp.79-90
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    • 2006
  • The partitioning level of a catchment becomes an issue if the calculated results from different levels show the same performance regardless of the levels. This study aims to identify the proper processing level of spatial resolution for the SWMM model application in an urban area. Using GIS overlaying technique, the division of subcatchments as a hydrologic similarity unit (HSU) is achieved with a comprehensive consideration of surface slope conditions, flow directions of storm sewers, and current land cover situation. Three surface-sewer alternatives are made on the basis of three different levels of surface divisions as well as the number of sewer connections and used as runoff simulation fields for the application of SWMM. As the result, it is found that the effect of a spatial resolution on the surface runoff results is not significant. On the other hand, the accumulated pollution load from an unit subcatchment, which is built by aggregation of several unit subcatchments consisting of various land cover conditions is reduced through the deterioration of surface spatial resolution. Although overall runoff pattern and accumulated runoff are little affected by spatial resolution, the simulated runoff from sewer outlet shows slight difference at the peak appearance time. The gap between surface pollution load accumulated and it discharged from the sewer outlet in a surface-sewer alternative during runoff period is monitored but the level of error is less than 5-10% except the lowest spatial resolution case.

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A Plan for a Prompt Disaster Response System Using a 3D Disaster Management System Based on High-Capacity Geographic and Disaster Information (고용량 지리정보 및 재난 정보 기반 3차원 재난 관리 시스템을 활용한 신속한 재난 대응 체계 방안 제시)

  • GANG, Su-Myung;KIM, Do-Ryeong;CHOUNG, Yun-Jae;PARK, Ju-Sung;KIM, Jin-Man;JO, Myung-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.1
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    • pp.180-196
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    • 2016
  • To minimize the damage from disasters, various aspects of prevention, preparation, and response, etc. are being managed. Even though prevention and preparation are well conducted, irresistible calamities such as natural disasters may cause unexpected damage. Therefore, a system that can share the identical disaster information based on prompt disaster management and prediction must be developed and constructed for integrated disaster management. Especially, for a prompt disaster response, the same information needs to be shared between the related organization and the disaster prevention personnel such as on-site officials. Recent disaster management systems use high-capacity geographic information or other various factors for accurate disaster predictions. In case of using a recently constructed or researched 3D GIS, the system may not be used in some cases due to conflicts with hardware, etc. Thus, even though response information is secured using prediction simulation in advance, it is essentially difficult in some cases to share the common information when the system cannot be utilized or the extension of the corresponding data cannot be read. Therefore, this study aims to construct a system for dealing with disasters that shares the same prompt and accurate information in compliance with common data formats. The system is expected to reduce the existing disaster response time and minimize human and physical damage by assisting decision making through prompt responses.

Kinematic Analysis of Plane Failure for Rock Slope Using GIS and Probabilistic Analysis Method (GIS와 확률론적 해석 기법을 기반으로 한 평면파괴의 운동학적 안정성 해석)

  • Lee, Seok Hwan;Park, Hyuck Jin
    • Economic and Environmental Geology
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    • v.47 no.2
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    • pp.121-131
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    • 2014
  • The stability of rock slope is mainly controlled by the orientation and shear strength of discontinuties in rock mass. Therefore, in kinematic analysis, the orientation of the combination of discontinuities and slope face is examined to determine if certain modes of failure can be occurred. In previous kinematic analysis, a representative orientation of the slope face and mean orientation of discontinuity set were used as input parameters. However, since the orientations of slope face varies according to locations of measurement, the representative slope face orientation could cause misunderstanding for kinematic instability. In addition, since the orientations of each discontinuity are scattered in the same discontinuity set, there is the possibility that uncertainties are involved in the procedure of kinematic analysis. Therefore, in this study, the detailed digital topographic map was used to obtain the orientation of slope face. In addition, the probabilistic analysis approach was utilized to deal properly with the uncertainties in discontinuity orientation. The proposed approach was applied to steep slopes in mountain road located in Baehuryeong, Chunncheon city, Gangwon-Do. The analysis results obtained from the deterministic and probabilistic analysis were compared to check the feasibility of proposed the analysis.