• Journal of the Korean Association of Geographic Information Studies
• /
• v.14 no.2
• /
• pp.28-39
• /
• 2011

This study estimates the characteristics of flow loads by classification items of the Ministry of Environment and by land cover change using HyGIS-SWAT. The result of analyzing the land cover change using the classification items shows that the urban area and the farmland area in Mishim-cheon and Gap-cheon are expanding while the forest area is decreasing. The result of analyzing the characteristics of classification items shows that peak discharge increases and total yearly discharge decreases in Mushim-cheon. The result of analyzing the characteristics by data-construction period shows that peak discharge decreases but total discharge increases in Gap-cheon. Three land cover change scenarios are applicable to the expansion of urban area and farmland area. According to the result of application, urbanization influences and Farmland area expansion influences increase peak discharge, total yearly discharge and sediment concentration.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_3
• /
• pp.921-932
• /
• 2023

Land cover change due to urban population concentration and urban expansion can cause various environmental problems such as urban heat islands. In particular, New towns are considered an appropriate study site to analyze changes in urban climate due to rapid urbanization in a short period. This study used Landsat satellite imagery to compare and analyze the land cover changes before and after the development of two new towns with different plans, and the resulting changes in surface urban heat island (SUHI) phenomena. Correlation analysis was also conducted between urban structural features that may affect the SUHI intensity. The results of the analysis confirm the rapid change in land cover as new town development progresses and the direct intensification of the SUHI phenomenon. This study confirms the differences in SUHI caused by different urban plans and suggests the need for three-dimensional urban planning to improve the thermal environment.

• Atmosphere
• /
• v.31 no.2
• /
• pp.143-156
• /
• 2021

This study investigates the impacts of land cover change due to urbanization on the Urban Heat Island Intensity (UHII) and the Heat Index (HI) over the Seoul metropolitan area using the Unified Model (UM) with the Met Office Reading Urban Surface Exchange Scheme (MORUSES) during the heat wave from 16, July to 5, August 2018. Two simulations are performed with the late 1980s land-use (EXP1980) and the late 2000s land-use (EXP2000). EXP2000 is verified using Automatic Weather Station (AWS) data from 85 points in the study area, and observation sites are classified into two categories according to the urban fraction change over 20 years; Category A is 0.2 or less increase, and Category B is 0.2 or more increase. The 1.5-m temperature and relative humidity in Category B increase by up to 1.1℃ and decreased by 7% at 1900 LST and 2000 LST, respectively. This means that the effect of the urban fraction changes is higher at night. UHII increases by up to 0.3℃ in Category A and 1.3℃ in Category B at 1900 LST. Analysis of the surface energy balance shows that the heat store for a short time during the daytime and release at nighttime with upward sensible heat flux. As a result of the HI, there is no significant difference between the two experiments during the daytime, but it increases 1.6℃ in category B during the nighttime (2200 LST). The results indicate that the urbanization increase both UHII, and HI, but the times of maximum difference between EXP1980 and EXP2000 are different.

• Journal of Korea Water Resources Association
• /
• v.36 no.4
• /
• pp.609-621
• /
• 2003

The purpose of this study is to evaluate the hydrological impact due to temporal land cover change by gradual urbanization of upstream watershed of Pyeongtaek gauging station of Anseong -cheon. WMS HEC-1 was adopted, and DEM with 200$\times$200m resolution and hydrologic soil group from 1:50,000 soil map were prepared. Land covers of 1986, 1990, 1994 and 1999 Landsat TM images were classified by maximum likelihood method. The watershed showed a trend that forest ＆ paddy areas decreased and urban/residential area gradually increased for the period of 14 years. The model was calibrated at 2 locations (Pyeongtaek and Gongdo) by comparing observed with simulated discharge results for 5 summer storm events from 1998 to 2001. The watershed average CN values varied from 61.7 to 62.3 for the 4 selected years. To identify the impact of streamflow by temporal area change of a target land use, a simple evaluation method that the CN values of areas except the target land use are unified as one representative CN value was suggested. By applying the method, watershed average CN value was affected in the order of paddy, forest and urban/residential, respectively.

• Journal of Wetlands Research
• /
• v.25 no.4
• /
• pp.315-325
• /
• 2023

This study analyzed the disturbance process of river wetlands based on modern and contemporary maps and aerial photographs, and analyzed land cover and NDVI changes in the hydro-ecological impact zone around the Wangjin District. A stable sandbar was formed near Wangjinnaru and was naturally connected to the agricultural land within inland, but after the sandbar and river wetland were destroyed due to heavy floods, embankment construction, land readjustment, and comprehensive river management, artificial replaced wetlands and ecological parks were created, and sandbars in the form of river island were restored again. The change in land cover in the hydro-ecological impact zone showed that rice paddies and fields in agricultural areas decreased from 36.3% in 2013 to 22.9% in 2022, with the largest change in area to 814,476m². It was confirmed that the land cover was undergoing vegetation over time. Since the vegetation condition is good, a healthy food chain is formed in the waterfront ecosystem, which can be expected to be biodiversity-positive. Summarizing seasonal changes in the vegetation index, the overall change in the vegetation index was the largest in spring (March), followed by summer (June), and the change in autumn (September) was the smallest except for water. By land use, the overall vegetation index (NDVI) increased, including 39.1% improvement in alternative wetlands, 38.2% improvement in load, 44.3% improvement in ecological parks, 35.6% improvement in agricultural areas, and -8.1% decrease in water.

• Journal of Forest and Environmental Science
• /
• v.28 no.3
• /
• pp.152-157
• /
• 2012

Sarawak is the largest state in Malaysia that covers 37.5% of the total land area. Multitemporal satellite images of Landsat and SPOT were used to examine deforestation and forest fragmentation in Sarawak between 1990 and 2009. Supervised classification with maximum likelihood classifier was used to classify the land cover types in Sarawak. The overall accuracies of all classifications were more than 80%. Our results showed that forests were reduced at 0.62% annually during the two decades. The peat swamp forest suffered a tremendous loss of almost 50% between 1990 and 2009 especially at coastal divisions due to intensified oil palm plantation development. Fragmentation analysis revealed the loss of about 65% of the core area of intact forest during the change period. The core area of peat swamp forest had almost completely disappeared during the two decades.

• Proceedings of the KSRS Conference
• /
• 2008.10a
• /
• pp.163-168
• /
• 2008

KOMPSAT-3 is expected to provide data with 80-cm spatial resolution, which can be used to detect environmental change and create thematic maps such as land-use and land-cover maps. However, to analyze environmental change, change-detection technologies that use multi-resolution and high-resolution satellite images simultaneously must be developed and linked to each other. This paper describes a GIS-based strategy and methodology for revealing global and local environmental change. In the pre-processing step, we performed geometric correction using satellite, auxiliary, and training data and created a new classification system. We also describe the available technology for connecting global and local change-detection analysis.

• Journal of Cadastre & Land InformatiX
• /
• v.46 no.2
• /
• pp.27-42
• /
• 2016

Forest accounts for almost 64 percents of total land cover in South Korea. For inventorying, monitoring, and managing such large area of forest, application of remote sensing and geographic information system (RS/GIS) technology is essential. On the basis of spectral characteristics of satellite imagery, forest cover and tree species can be classified, and forest cover map can be prepared. Using three dimensional data of LiDAR(Light Detection and Ranging), tree location and tree height can be measured, and biomass and carbon stocks can be also estimated. In addition, many indices can be extracted using reflection characteristics of land cover. For example, the level of vegetation vitality and forest degradation can be analyzed with VI (vegetation Index) and TGSI (Top Grain Soil Index), respectively. Also, pine wilt disease and o ak w ilt d isease c an b e e arly detected and controled through understanding of change in vegetation indices. RS and GIS take an important role in assessing carbon storage in climate change related projects such as A/R CDM, REDD+ as well. In the field of climate change adaptation, impact and vulnerability can be spatio-temporally assessed for national and local level with the help of spatio-temporal data of GIS. Forest growth, tree mortality, land slide, forest fire can be spatio-temporally estimated using the models in which spatio-temporal data of GIS are added as influence variables.

• Korean Journal of Remote Sensing
• /
• v.27 no.3
• /
• pp.259-276
• /
• 2011

Short-term land cover changes, such as forest fire scar and crop harvesting, can be detected by high temporal resolution satellite imagery like MODIS and AVHRR. Because these optical satellite images are often obscured by clouds, the static cloud-free composite methods (maximum NDVI, minblue, minVZA, etc.) has been used based on non-overlapping composite period (8-day, 16-day, or a month). Due to relatively long time lag between successive images, these methods are not suitable for observing short-term land cover changes in near-real time. In this study, we suggested a new dynamic cloud-free composite algorithm that uses cut-and-patch method of cloud-masked daily MODIS data using MOD35 products. Because this dynamic composite algorithm generates daily cloud-free MODIS images with the most recent information, it can be used to monitor short-term land cover changes in near-real time. The dynamic composite algorithm also provides information on the date of each pixel used in compositing, thereby makes accurately identify the date of short-term event.

• Journal of the Korean GEO-environmental Society
• /
• v.20 no.12
• /
• pp.33-39
• /
• 2019

The upsurge of population, internal migration, economic activities and developmental works has brought significant land use and land cover (LULC) change over the period of 1990 and 2010 in the Bagmati basin of Nepal. Along with alteration on various other ecosystem services like water yield, water quality, soil loss etc. carbon sequestration is also altered. This study thus primary deals with evaluation of LULC change and its impact on the soil carbon storage for the period 1990 to 2010. For the evaluation, InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Carbon model is used. Residential and several other infrastructural development activities were prevalent on the study period and as a result in 2010 major soil carbon reserve like forest area is decreased by 7.17% of its original coverage in 1990. This decrement has brought about a subsequent decrement of 1.39 million tons of carbon in the basin. Conversion from barren land, water bodies and built up areas to higher carbon reserve like forest and agriculture land has slightly increased soil carbon storage but still, net reduction is higher. Thus, the spatial output of the model in the form of maps is expected to help in decision making for future land use planning and for restoration policies.