• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.66-77
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• 2005

We have investigated microclimatic controls on the spatiotemporal variations of net primary production (NPP) of a rugged forested watershed using the process-based biogeochemical model (BIOME-BGC). To validate the model simulation of water and carbon cycles at the plot scale, we have conducted field survey over deciduous broadleaf forest (DBF) and evergreen needleleaf forest (ENF) since 2000. The modeled values of soil temperature, soil moisture and soil respiration showed high correlation with those from the field measurements. The modeled seasonal changes of NPP showed high correlation with air temperature but no significant correlation with water related parameters. The precipitation frequency turned out to be the best climatic factor to explain the annual variation of NPP. Furthermore, NPP of ENF was more sensitive to precipitation frequency than that of DBF. With changes in vegetation cover and topography, the spatial distribution of NPP was of great heterogeneity, which was negatively correlated with the magnitude of NPP. Despite the annual precipitation of 1,400mm, NPP at the study site was constrained by the amount of water available for the vegetation. Such a modeling result should be verified by the field measurements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1B
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• pp.29-36
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• 2011

Evapotranspiration (ET) from the various surfaces needs to be understood because it is a crucial hydrological factor to grasp interaction between the land surface and the atmosphere. A traditional way of estimating it, which is calculating it empirically using lysimeter and pan evaporation observations, has a limitation that the measurements represent only point values. However, these measurements cannot describe ET because it is easily affected by outer circumstances. Thus, remote sensing technology was applied to estimate spatial distribution of ET. In this study, we estimated major components of energy balance method (i.e. net radiation flux, soil heat flux, sensible heat flux, and latent heat flux) and ET as a map using Mapping Evapo-Transpiration with Internalized Calibration (METRIC) satellite-based image processing model. This model was run using Landsat imagery of Gyeongan watershed in Korea on Feb 1, 2003 and Sep 13, 2006. Basic statistical analyses were also conducted. The estimated mean daily ETs had respectively 22% and 11% of errors with pan evaporation data acquired from the Suwon Weather Station. This result represented similar distribution compared with previous studies and confirmed that the METRIC algorithm had high reliability in the watershed. In addition, ET distribution of each land use type was separately examined. As a result, it was identified that vegetation density had dominant impacts on distribution of ET. Seasonally, ET in a growing season represented significantly higher than in a dormant season due to more active transpiration. The ET maps will be useful to analyze how ET behaves along with the circumstantial conditions; land cover classification, vegetation density, elevation, topography.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.61-72
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• 2008

Leaf area index (LAI) is a key biophysical variable influencing land surface processes such as photosynthesis, transpiration and energy balance, and is a required input to estimate evapotranspiration in various ecological and hydrological models. The development of more correct and useful LAIs estimation techniques is required by these importance, but LAIs had been assumed in most LAI research through simple relations with the normalized difference vegetation index (NDVI) because the field measurement is difficult on wide area. This paper is to evaluate the MODIS LAI Product's practical use by comparing with LAIs that is derived from NOAA AVHRR NDVIs and the 2 years (2003-2004) measured LAIs of Korea Forest Research Institute in Gyeongancheon watershed (561.12 $Km^2$). As a result, the MODIS LAIs of deciduous forests showed higher values about 14 % and 15~30 % than the measured LAIs and NOAA LAIs. In the year of 2003, the MODIS LAIs in coniferous forests were 5 % higher than the measured LAIs, and showed about 7 % differences comparing with the NOAA LAIs except April. These differences come from the insufficient field data measured in partial points of the target area, and the extracted reference data from MODIS LAIs include the limits of spatial resolution and the error of incorrect land cover classification. Thus, using the MODIS data by the proper correction with the measured data can be useful as an input data for ecological and hydrological models which offers the vegetation information and simulates the water balance of a given watershed.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.22-32
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• 2015

This study investigated the difference in fish community structures in a main channel and an isolated former channel, considering the environmental factors in the Mangyeong River, Korea. Principal component analysis (PCA) with environmental factors showed that former channels were composed of a fine substrate covered by in-stream vegetation, whereas the main channel was covered by a wide range of substrates with a higher dissolved oxygen and conductivity. The result of the hierarchical cluster analysis with species abundance delineated to the four main groups; three abandoned channel groups and one main channel group. Non-metric multidimensional scaling (NMDS) showed that fish community structures of each study site differed from environmental factors: former channel fish communities were positively related to in-stream vegetation cover, whereas main channel fish communities were positively associated with dissolved oxygen and conductivity. The results indicated that channelization, where there was a separation between the former channel and the main channel, had detrimental effects on fish community structures of both the main channel and the abandoned channel in the Mangyeong River. In conclusion, this study suggested that the connectivity between the main channel and abandoned channel were required to enhance both habitat structural diversity and species diversity of the Mangyeong River.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.454-461
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• 2015

This study aims to classify the biotope types based on the vegetation community in built-up areas by different land use and to map the plant communities. By classifying biotopes according to a taxonomic system, the characteristics of a biological community can be well-represented. The biotope classification indexes for the target area include human behavioral factors such as land use intensity, land-use patterns and land-cover types. The type classification was divided into four hierarchic ranks starting with Biotope Class, next by Biotope Group and Biotope Type and lastly by Biotope Sub-Type. The Biotope Class was first divided into two areas: the areas improved by humans and the areas unimproved by humans. The improved areas were again divided into permeable and non-permeable regions on the Biotope Group level. In the Biotope Type level, permeable paving areas were divided into areas with wide gap pavers and those with narrow gap pavers. The differential species of each biotope type are Lindera glauca, Conyza canadensis, Mazus pumilus, Vicia tetrasperma, Crepidiastrum sonchifolium, Zoysis japonica, Potentilla supina and Festuca arundinacea. The results of this study suggest that the biotope classification methodology, using a subjective phytosociological approach, is a useful and valuable tool and the results also suggest the possibility of applying more objective and scientific methods in mapping and classifying various environments.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.973-983
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• 2020

Recently, SAR (Synthetic Aperture Radar) is being highlighted as a solution to the coarse spatial resolution of remote sensing data in water resources research field. Spatial resolution up to 10 m of SAR backscattering coefficient has facilitated more elaborate analyses of the spatial distribution of soil moisture, compared to existing satellite-based coarse resolution (>10 km) soil moisture data. It is essential, however, to multilaterally analyze how various hydrological and environmental factors affect the backscattering coefficient, to utilize the data. In this study, soil moisture estimated by WCM (Water Cloud Model) and linear regression is compared with in-situ soil moisture data at 5 soil moisture observatories in the Korean peninsula. WCM shows suitable estimates for observing instant changes in soil moisture. However, it needs to be adjusted in terms of errors. Soil moisture estimated from linear regression shows a stable error range, but it cannot capture instant changes. The result also shows that the effect of soil moisture on backscattering coefficients differs greatly by land cover, distribution of vegetation, and water content of vegetation, hence that there're still limitations to apply preexisting models directly. Therefore, it is crucial to analyze variable effects from different environments and establish suitable soil moisture model, to apply SAR to water resources fields in Korea.

• Journal of Environmental Science International
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• v.12 no.11
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• pp.1181-1187
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• 2003

Hibiscus hamabo, called "Hwang-geun", growing about 3m in height is a deciduous shrub or subtree of Malvaceae. Because the number of these species is very limited in the world, the Ministry of Environment has designated H. hamabo as a preserved plant. The Korea Forest Service also protects it strictly by law since H. hamabo is an out-of-the-way plant and possibly may be exterminated soon in Korea. Investigation for distribution and ecological characteristics of the habitat for H. hamabo was carried out on Soan Island. Two wild H. hamabo were found at the forest edge (equation omitted) along the sea coast located in the southern part of Soan Island and this was the first report in the Korean academic world. These two wild H. hamabos were growing in a naturally inhibited area. The diameters at the base were 12cm and 15cm. The Tree heights were 150cm and 210cm and the number of branches of each wild H. hamabo was 4 and 7. However, the present condition of these plants was not good. Environmental conditions of the naturally inhibited area of H. hamabo were very mild because it is located at the edge of the forest and is always sunny during the daytime since the slope of the inhibited area is facing South. The ground drained very well since the soil was made of gravels and sand. Because the percent of vegetation of the subtree layer where H. hamabo was growing was 40%, the cover degree and sociability of flex crenata trees and Eurya japonica were found to be high. In the naturally inhibited area of H. hamabo, a dominant value of Rubus parvifolius in the lower part of the herb layer was very high and many plants in Compositae, such as Artemisia princeps var. orientalis and Erigeron annuus, were also present. A dominant value of liana, such as Vitis thunbergii var. sinuata, Rosa multiflora, Clematis terniflora and Hedera rhombea, and Gramineae plants that rhizomes were well developed and aggressively propagated, such as Miscanthus sinensis var. purpurascens, Phragmites communis, Spodiopogon cotulifer and Oplismenus undulatifolius which were surveyed as high, too. These results imply that H. hamabo might be exterminated soon through a natural selection if the proper management of the naturally inhibited area of H. hamabo is not conducted continually.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.1-9
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• 2017

Forest harvest as large scale artificial disturbance makes edge environment in both clear-cutted and forested habitat. To clarify the development and recovery process of forest edge after disturbances is essential to understand vegetation responses and landscape level consequences such as edge-distance. In Korea, after clear-cutting, edge-related changes of environment and vegetation was not clarified yet. In Korean red pine (Pinus densiflora) forest, by applying space-for-time approach (sites with undisturbed and 1, 3, 10, 16 yr after cutting), the edge-related change of plant abundance and abiotic factors were determined for 20 line-transect (60 m) and 340 ($1m{\times}5m$) quadrats, and clarified depth and duration of the disturbance. Immediately after edge formation, within 15m form the edge, biotic and abiotic factors such as cover, richness, canopy openness, temperature and moisture content exhibited larger changes compared to forest interior. Plant abundance and abiotic variables were stabilized at the level of forest inside within 16 yr and 10 yr after edge creation, respectively. Woody (tree and shrub) species generally was showed larger increment with proximity to edge than did herb or graminoid species. In addition, negative interactions between woody and herbaceous species were detected during the period of forest edge closure. Our results suggested that depth of forest edge formed by clear-cutting of Korean red pine forest was at least from 15 m to 20 m and edge effect were likely sustained more than 16 years. As the first empirical study on edge-distance between two contrast habitats of clear-cutted and adjacent forest in South Korea, the analytical reality on landscape structure and habitat patches can be improved.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.155-163
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• 1997

The Mongolian ger is ideally suited to the mongol's steppe climate and the nomadic way of life. This is a multipurpose dwelling which can be easily collapsed, transported to another place and put up again fully preserving its original shape. The pastoral nomadic ger has two key components: the wooden framework and the felt cover. The wooden parts are the walls(khana), the long poles(un), the smoke escape(toono) and its supports(bagana). One wall consists of 10-15 branches of willow tree. each about 1.5m high bound together in a way making it possible to fold it for transportation and then unfold it like an accordion. The unfolded walls are connected to form a circle. The long poles(un) are fastened to the upper part of the walls, with the other end passed through the toono hole, the only sky window and smoke escape through it from the ger. The toono is propped up by two posts, called bagana. All this forms the wooden framework of the ger, which is covered with felt. When the herders fire up their metal stoves, the temperature inside the ger becomes quite comfortable. Because the nomads live in a climate where there is only one growing season in a year, they do not make long migrations to new pastures. Livestock subsist on standing vegetation for eight months of the year. The basic pasture migration strategy is to leave enough standing vegetation at the end of the growing season in September to suffice until the new growth appears the following May. Mongolians use a type of compressed tea leaf that is called "brick" tea in English because it is rock solid and roughly the shape of a brick. And they consume a larger percent(88%) of fat from animal products such as meat, milk, butter, and cheese than any other people in the world. Milk products made from the milk of sheep, yak, and goats are major foods in the nomad's diet, but they are produced mainly in summer when all the animals are lactating. Mongolians made their special nomadic food culture on the steppe.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.13-20
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• 2009

Techniques for change detection using satellite images enable efficient detection of natural and artificial changes in use of land through multi-phase images. As for change detection, different results are made based on methods of calibration of satellite images, types of input data, and techniques in change analysis. Thus, an analytic technique that is appropriate to objectives of a study shall be applied as results are different based on diverse conditions even when an identical satellite and an identical image are used for change detection. In this study, Normalized Difference Vegetation Index (NDVI) and Principal Component Analysis (PCA) were conducted after geometric calibration of satellite images which went through absolute and relative radiometric calibrations and change detection analysis was conducted using Image Difference (ID) and Image Rationing (IR). As a result, ID-NDVI showed excellent accuracy in change detection related to vegetation. ID-PCA showed 90% of accuracy in all areas. IR-NDVI had 90% of accuracy while it was 70% and below as for paddies and dry fields${\rightarrow}$grassland. IR-PCA had excellent change detection over all areas.