• 한국농림기상학회지
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• 제3권3호
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• pp.143-149
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• 2001

각 지역의 겨울철 강수인 눈의 산성도와 화학적 조성과 산림지역의 임내ㆍ외 강설의 특성을 비교 분석하고자 대관령 지역(강원도 평창군 도암면 횡계리) 운교 지역(강원도 평창군 방림면 운교리)을 대상으로 강설을 채취하여 분석한 결과를 요약하면 다음과 같다. 1. 조사 지역의 강설을 채취하여 적설량과 pH의 관계를 보면, 두 지역 모두 적설량이 적을 때는 pH의 변화 분포가 크게 나타났으며, 적설량이 증가할수록 pH가 안정되는 경향을 보였다. 이와 같은 결과는 강우현상에 있어 국지적인 환경에 따른 대기중의 부유물질 중에서 산성물질의 흡착비율이 달라짐을 의미함과 동시에 광역적으로 분포하는 산성물질의 유입도 고려해야 한다는 연구(나춘기와 정재일, 1997)와 유사한 것으로 강설의 경우에도 적용할 수 있다고 판단하였다. 2. 각 조사 지역의 강설 중 임외 강설과 임내 강설의 이온농도 변화는 전체적으로 임내에서 증가하는 경향을 보였다. 이 중에서 양이온의 경우는 $Ca^{2+}$, 음이온은 NO$_{3}$$^{-}$, SO$_{4}$$^{2-}$ , Cl$^{-}$ 모두가 증가의 양상을 보였다. 3. 이러한 결과를 기초로 하여 각 이온농도간의 편차와 상호관계를 파악하기 위해서 각 이온간의 상관성과 요인분석을 실시하여 비교하는 것이 각 지역 강설의 화학적 특성을 구명할 수 있을 것으로 판단된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.241-246
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• 2005

Doam watershed is located at alpine areas in the Kangwon province. The annual average precipitation, including snow accumulation during the winter, at the Doam watershed is significantly higher than other areas. Thus, pollutant laden runoff and sediment discharge from the alpine agricultural fields are causing water quality degradation at the Doam watershed. To estimate soil erosion from the agricultural fields, the Universal Soil Loss Equation (USLE) has been widely used because of its simplicity to use. The USLE rainfall erosivity (R) factor is responsible for impacts of rainfall on soil erosion. Thus, use of constant R factor for the Doam watershed cannot reflect variations in precipitation patterns, consequently soil erosion estimation. In the early spring at the Doam watershed, the stream flow increases because of snow melt, which results in erosion of loosened soil experiencing freezing and thaw during the winter. However, the USLE model cannot consider the impacts on soil erosion of freezing and thaw of the soil. Also, it cannot simulate temporal changes in USLE input parameters. Thus, the Soil and Water Assessment Tool (SWAT) model was investigated for its applicability to estimate soil erosion at the Doam watershed, instead of the widely used USLE model. The SWAT hydrology and erosion/sediment components were validated after calibration of the hydrologic component. The $R^2$ and Nash-Sutcliffe coefficient values are higher enough, thus it was found the SWAT model can be efficiently used to simulate hydrology and sediment yield at the Doam watershed. The effects of snow melt on SWAT estimated stream flow and sediment were investigated using long-term precipitation and temperature data at the Doam watershed. It was found significant amount of flow and sediment in the spring are contributed by melting snow accumulated during the winter. Thus, it is recommend that the SWAT model capable of simulating snow melt and long-term weather data needs to be used in estimating soil erosion at alpine agricultural land instead of the USLE model for successful soil erosion management at the Doam watershed.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2009년도 춘계학술발표회 논문집
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• pp.35-39
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• 2009

균일한 분포를 갖는 지형자료와 중력자료는 정밀 지오이드 모델의 정밀도에 결정적인 영향을 미친다. 본 연구에서는 시뮬레이션 실험을 통하여 현재 편중된 분포를 갖는 우리나라 지상중력자료를 이용하여 정밀도 5cm급의 정밀 지오이드 모델을 구축할 때 지상중력자료가 보충되어야 할 지역을 선정하였다. 시뮬레이션 결과 현재 우리나라 지상중력자료의 분포 및 정밀도는 8cm 정도의 지오이드 오차를 유발하는 것으로 나타났고, 이때 오차가 30cm 이상인 지점(주로 강원도 산악지역)에 2km 간격의 중력자료를 추가한 경우 5cm 정도의 지오이드 오차를 유발하는 것으로 나타났다. 따라서 5cm급의 정밀 지오이드 모델을 구축하기 위해서는 강원도 산악지역에 2km 이하의 간격으로 중력보완측량을 실시하여 자료를 보완하는 것이 필수적이라 판단된다.

• 한국환경복원기술학회지
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• 제3권4호
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• pp.52-59
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• 2000

This study was carried out to find out effect of by-product gypsum on reducing soil erosion at the sloping burned area at Sampo-ri, Gosung-gun in Kangwon-province during the period between June 28 and Sept. 30, 2000. Four experimental plots ($1.2m{\times}10m$) were prepared at the study area with slopes $15^{\circ}{\sim}18^{\circ}$ where forest fire took place twice during last 4 years. Phosphogypsum (PG) was applied to the soils of the 4 plots at the rates of 0 (control), 5, 7.5, and 10 ton/ha, respectively. Amount of rainfall, runoff, and soil loss were measured 7 times during the study. In the beginning, the amounts of runoff and soil loss from the PG treated plots were not different from those from the control plot due to steepness of the plots. However, the difference between the amount of runoff and soil loss from the PG treated plots and those from the control became apparent over time. The effect of PG treatment lasted until at least 870 mm of rainfall. Compared to the cumulative runoff from the control plot, the cumulative runoff from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 7%, 31 %, and 35%, respectively. The cumulative soil loss from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 44%, 53%, and 77% compared to that from the control plot. Strong acidity of PG (pH 2.0~2.5) did not affect the acidity of the soil and runoff.

• 대한지리학회지
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• 제45권5호
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• pp.573-591
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• 2010

이 연구에서는 지난 100년(1908~2007) 동안 서울에서 발생한 열파의 변화추세와 극심한 열파 발생 시 도심내 열환경과 사망자의 시공간적 패턴을 분석하고자 한다. 최근의 온난화 경향에도 불구하고 여름철 강수량증가에 의해 서울시의 열파 발생빈도 및 강도에는 뚜렷한 변화경향이 관찰되지 않는다. 전례 없이 강한 열파가 발생한 1994년 7월의 자동기상관측 및 Landsat TM 위성 영상 추출 열분포 자료들은 도심내 형성되는 고온의 열환경에 의해 노인 질병 사망자 수가 더욱 증가하였음을 잘 보여준다. 이 연구는 차후 도심 정비시 열환경 분포를 고려해야 하는 생리기후학적 근거를 제시하고 있다.

• 한국농공학회논문집
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• 제59권1호
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• pp.57-70
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• 2017

In this study, we evaluated daily root zone soil moisture dynamics and agricultural drought using a near-surface soil moisture data assimilation scheme with Soil Moisture Active & Passive (SMAP, $3km{\times}3km$) soil moisture footprints under different hydro-climate conditions. Satellite-based LANDSAT and MODIS image footprints were converted to spatially-distributed soil moisture estimates based on the regression model, and the converted soil moisture distributions were used for assessing uncertainties and applicability of SMAP data at fields. In order to overcome drawbacks of the discontinuity of SMAP data at the spatio-temporal scales, the data assimilation was applied to SMAP for estimating daily soil moisture dynamics at the spatial domain. Then, daily soil moisture values were used to estimate weekly agricultural drought based on the Soil Moisture Deficit Index (SMDI). The Yongdam-dam and Soyan river-dam watersheds were selected for validating our proposed approach. As a results, the MODIS/SMAP soil moisture values were relatively overestimated compared to those of the TDR-based measurements and LANDSAT data. When we applied the data assimilation scheme to SMAP, uncertainties were highly reduced compared to the TDR measurements. The estimated daily root zone soil moisture dynamics and agricultural drought from SMAP showed the variability at the sptio-temporal scales indicating that soil moisture values are influenced by not only the precipitation, but also the land surface characteristics. These findings can be useful for establishing efficient water management plans in hydrology and agricultural drought.

• 한국지진공학회논문집
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• 제18권4호
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• pp.171-180
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• 2014

Since the execution of structural design by professional structural engineers is not mandatory for small-size buildings in Korea, structural design is conducted by architects or contractors resulting in concern about the seismic safety of the buildings. Therefore, the Korean Structural Engineers Association proposed dedicated structural design criteria in 2012. The criteria were developed based on a deterministic approach in which the structural members are designed only with information of story and span length of the buildings and without structural analyses. However, due to the short time devoted to their development, these criteria miss satisfactory basis and do not deal with structural walls popularly used in Korea. Accordingly, the Ministry of Land, Infrastructure and Transport launched a research on the 'development of structural performance enhancement technologies for small-size buildings against earthquakes and climate changes'.. As part of this research, this paper intends to establish direction for the preparation of deterministic structural design guidelines for seismic safety of domestic small-size reinforced concrete buildings. To that goal, a typical plan of these buildings is selected considering frames only and frames plus walls, and then design is conducted by changing the number of stories and span length. Next, the seismic performance is analyzed by nonlinear static pushover analysis. The results show that the structural design guidelines should be developed by classifying frames only and frames plus walls. The size and reinforcement of structural elements should be provided in the middle level of the current Korean Building Code and criteria for small buildings by considering story and span length for buildings with frames only, and determined by considering the shape and location of walls and the story and span length as well for buildings with frames plus walls. It is recommended that the design of walls should be conducted by reducing the amount of walls along with symmetrically located walls.

• Journal of Ecology and Environment
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• 제41권2호
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• Journal of Forest and Environmental Science
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• 제29권2호
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• pp.147-156
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• 2013

Multiple use forestry is capable of generating income for forest based communities through Non-Timber forest products (NTFPs) which provide food, medicine, materials for domestic use and cash income for communities adjoining forest areas in developing countries. This study evaluates the economics of producing ginger rhizomes under teak canopy in a multiple land use system during 2007 and 2008 in even aged teak plantations in Ibadan and Ife, Nigeria. Twelve $6m^2$ sample plots were randomly selected in Completely Randomized Block Design within and outside the plantation. Average ginger rhizome of (50-60 g) were planted on the slightly tilled soil. NPK 15:15:15 was applied at 180 kg/ha on a split unit dose. ANOVA, Profitability, Benefit-Cost (B/C) ratio were used to analyze data. Results showed no significant differences between sites in ginger rhizome yield, (0.089 and 0.718, ${\rho}{\leq}0.05$) in 2007 and 2008 respectively. Average yield were higher outside teak canopy in both sites and treatments, (Ibadan -40.05 g>32.9 g, Ife -67.6 g>25.2 g and Ibadan -41.3 g>31.5 g, Ife -66.8 g>25.0 g) with and without NPK respectively. NPK had no effect on yields within teak plantation, (Ibadan -31.5<32.9 g, Ife -25 g<25.2 g). Ginger rhizome production was viable financially without inorganic fertilizer during second cropping season within and outside plantation (B/C=1.02, 1.09) respectively. Ginger could be raised profitably under teak canopy, however, studies on insolation requirement of ginger under teak canopy and other tree plantations are recommended.

• Journal of Ecology and Environment
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• 제30권2호
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• pp.121-126
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• 2007

We monitored gold-spotted pond frog (Rana chosenica) populations near the Korea National University of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 22 individuals (19 males and 3 females) were captured between 23 May and 15 June. No peak in breeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps $1{\sim}9$) than in traps facing hilly land (0.33, traps $13{\sim}18$). Comparative data from the Korean frog (Rana coreana), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.