• 한국환경과학회지
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• 제5권6호
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• pp.727-738
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• 1996

An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of Tf(foliage temperature), Tg(ground temperature), and qg(ground specific humidity). The model was verilied by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soil(sand and peat), the change for shielding factor, and the change for a kind of vegetation.

• 한국토양비료학회지
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• 제36권2호
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• pp.92-103
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• 2003

Research and technological advances in the field of remote sensing have greatly enhanced the ability to detect and quantify physical and biological stresses that affect the productivity of agricultural crops. Reflectance in specific visible and near-infrared regions of the electromagnetic spectrum have proved useful in detection of nutrient deficiencies. Especially crop canopy sensors as a ground remote sensing measure the amount of light reflected from nearby surfaces such as leaf tissue or soil and is in contrast to aircraft or satellite platforms that generate photographs or various types of digital images. Multi-spectral vegetation indices derived from crop canopy reflectance in relatively wide wave band can be used to monitor the growth response of plants in relation to environmental factors. The normalized difference vegetation index (NDVI), where NDVI = (NIR-Red)/(NIR+Red), was originally proposed as a means of estimating green biomass. The basis of this relationship is the strong absorption (low reflectance) of red light by chlorophyll and low absorption (high reflectance and transmittance) in the near infrared (NIR) by green leaves. Thereafter many researchers have proposed the other indices for assessing crop vegetation due to confounding soil background effects in the measurement. The green normalized difference vegetation index (GNDVI), where the green band is substituted for the red band in the NDVI equation, was proved to be more useful for assessing canopy variation in green crop biomass related to nitrogen fertility in soils. Consequently ground remote sensing as a non destructive real-time assessment of nitrogen status in plant was thought to be useful tool for site specific crop nitrogen management providing both spatial and temporal information.

• 한국습지학회지
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• 제11권1호
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• pp.105-113
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• 2009

연안습지 생태계에서 열에너지 교환 과정은 매우 중요하다. 지표 열에너지 평형을 이루는 요소인 순복사플럭스, 현열 플럭스, 잠열 플럭스 그리고 토양열 플럭스를 전라남도 고흥에 위치한 수평적으로 균질하다고 판단되는 지역인 고흥만 간척지에서 관측하고 분석하였다. 열의 수송을 평가하기 위해서 5회의 집중관측 기간에 대기 난류를 측정하였고, 특히 갈대로 덮여있는 간척지에서 지표층 열에너지 수지를 분석하기 위해서는 물과 매우 미세한 입자로 구성된 토양 그리고 계절에 따라 색깔과 밀도가 변하는 식생캐노피를 고려하였다. 순복사 플럭스, 현열 플럭스, 잠열 플럭스, 토양열 플럭스를 기존의 에너지 수지방정식에 적용하여 식생과 토양과 같은 지표면 특성에 따른 열 플럭스의 특징을 조사하여 습지의 기온조절 효과에 대해 알아보았다. 에너지 수지비로 식생 성장기에는 주로 잠열 플럭스에 의해 열이 대기로 전달되는 것을 알 수 있었다. 또한 식생층은 열을 저장하여 기온의 일교차를 줄이는 역할을 한다. 여름철에 집중관측지의 기온이 주변 지역의 기온보다 보다 낮고 겨울철에는 다소높게 나타난 결과는 식생층을 포함하는 연안습지가 열환경을 조절함을 보여주었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.325-328
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• 2007

We discuss the Normalized Difference Vegetation Index (NDVI) of the forest canopy and floor separately based on airborne spectral reflectance measurements and simultaneous airborne land surface images acquired around Yakutsk, Siberia in 2000. The aerial land surface images were visually classified into four forest types: no-green canopy and snow floor (Type-1), green canopy and snow floor (Type-2), no-green canopy and no-snow floor (Type-3), and green canopy and no-snow floor (Type-4). The mean NDVI was calculated for these four types. Although Type-2 had green canopy, the NDVI was rather small (0.17) because of high reflection from the snow cover on the floor. Type-3, which had no green canopy, indicated considerably large NDVI (0.45) due to the greenness of the floor. Type-4 had the largest NDVI (0.75) because of the greenness of both the canopy and floor. These results reveal that the NDVI depends considerably on forest floor greenness and snow cover in addition to canopy greenness.

• 한국토양비료학회지
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• 제43권3호
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• pp.260-267
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• 2010

As sloped farmland is subject to runoff and soil erosion and consequently require appropriate vegetative coverage to conserve soil and water, a field study was carried out to evaluate the impact of crop canopy coverage on soil loss and runoff from the experimental plot with three different textural types (clay loam, loam, and sandy loam). The runoff and soil loss were examined at lysimeters with 15% slope, 5 m in length, and 2 m in width for five months from May to September 2009 in Suwon ($37^{\circ}$ 16' 42.67" N, $126^{\circ}$ 59' 0.11" E). Red pepper (Capsicum annum L. cv. Daechon) seedlings were transplanted on three different dates, May 4 (RP1), 15 (RP2), and 25 (RP3) to check vegetation coverage. During the experimental period, the vegetation coverage and plant height were measured at 7 day-intervals and then the 'canopy cover subfactor' (an inverse of vegetation cover) was subsequently calculated. After each rainfall ceased, the amounts of soil loss and runoff were measured from each plot. Under rainfall events >100 mm, both soil loss and runoff ratio increased with increasing canopy cover subfactor ($R^2$=0.35, p<0.01, $R^2$=0.09, p<0.1), indicating that as vegetation cover increases, the amount of soil loss and runoff reduces. However, the soil loss and runoff were depending on the soil texture and rainfall intensity (i. e., $EI_{30}$). The red pepper canopy cover subfactor was more highly correlated with soil loss in clay loam ($R^2$=0.83, p<0.001) than in sandy loam ($R^2$=0.48, p<0.05) and loam ($R^2$=0.43, p<0.1) plots. However, the runoff ratio was effectively mitigated by the canopy coverage under the rainfall only with $EI_{30}$<1000 MJ mm $ha^{-1}hr^{-1}$ ($R^2$=0.34, p<0.05). Therefore, this result suggested that soil loss from the red pepper field could be reduced by adjusting seedling transplanting dates, but it was also affected by the various soil textures and $EI_{30}$.

• Journal of Ecology and Environment
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• 제34권2호
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• pp.149-156
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• 2011

Phenological variables derived from remote sensing are useful in determining the seasonal cycles of ecosystems in a changing climate. Satellite remote sensing imagery is useful for the spatial continuous monitoring of vegetation phenology across broad regions; however, its applications are substantially constrained by atmospheric disturbances such as clouds, dusts, and aerosols. By way of contrast, a tower-based ground remote sensing approach at the canopy level can provide continuous information on canopy phenology at finer spatial and temporal scales, regardless of atmospheric conditions. In this study, a tower-based ground remote sensing system, called the "Phenological Eyes Network (PEN)", which was installed at the Gwangneung Deciduous KoFlux (GDK) flux tower site in Korea was introduced, and daily phenological progressions at the canopy level were assessed using ratios of red, green, and blue (RGB) spectral reflectances obtained by the PEN system. The PEN system at the GDK site consists of an automatic-capturing digital fisheye camera and a hemi-spherical spectroradiometer, and monitors stand canopy phenology on an hourly basis. RGB data analyses conducted between late March and early December in 2009 revealed that the 2G_RB (i.e., 2G - R - B) index was lower than the G/R (i.e., G divided by R) index during the off-growing season, owing to the effects of surface reflectance, including soil and snow effects. The results of comparisons between the daily PEN-obtained RGB ratios and daily moderate-resolution imaging spectroradiometer (MODIS)-driven vegetation indices demonstrate that ground remote sensing data, including the PEN data, can help to improve cloud-contaminated satellite remote sensing imagery.

• 대한원격탐사학회지
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• 제28권3호
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• pp.297-305
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• 2012

This study was performed to estimate forest canopy density (FCD) using airborne hyperspectral data acquired in the Independence Hall of Korea in central Korea. The airborne hyperspectral data were obtained with 36 narrow spectrum ranges of visible (Red, Green, and Blue) and near infrared spectrum (NIR) scope. The FCD mapping model developed by the International Tropical Timber Organization (ITTO) uses vegetation index (VI), bare soil index (BI), shadow index (SI), and temperature index (TI) for estimating FCD. Vegetation density (VD) was calculated through the integration of VI and BI, and scaled shadow index (SSI) was extracted from SI after the detection of black soil by TI. Finally, the FCD was estimated with VD and SSI. For the estimation of FCD in this study, VI and SI were extracted from hyperspectral data. But BI and TI were not available from hyperspectral data. Hyperspectral data makes the numerous combination of each band for calculating VI and SI. Therefore, the principal component analysis (PCA) was performed to find which band combinations are explanatory. This study showed that forest canopy density can be efficiently estimated with the help of airborne hyperspectral data. Our result showed that most forest area had 60 ~ 80% canopy density. On the other hand, there was little area of 10 ~ 20% canopy density forest.

• 한국환경생태학회지
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• 제28권2호
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• pp.205-214
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• 2014

본 연구는 부산광역시 지정 기념물 제 46호인 동백섬에 대해 문화경관림으로서의 식생관리방안을 제시하고자 하였다. 연구대상지는 동백섬 내 자연휴식년제 지역인 정상부 주변 $20,000m^2$이었다. 지형, 식생, 식생관리현황을 기준으로 식생구조 유형을 분류하였으며 유형별 식물군집구조 분석을 통해 관리방안을 도출하였다. 식생구조 유형은 관리되고 있는 동백나무림, 관리되지 않은 사스레피나무림, 험준지의 미관리된 사스레피나무림 등 3개로 구분되었으며, 식물군집구조 분석결과, 교목층에서는 곰솔이 우점하였고 아교목층에서는 동백나무(유형 I), 사스레피나무(유형II, III)가 우점하였다. 특히, 관목층을 중심으로 난대림의 극상수종인 후박나무가 일부 분포하였다. 흉고직경급별 분석결과, 유형 I, II에서 중경목의 팽나무와 후박나무가 일부 분포하였고 모든 유형의 관목층에서 후박나무가 4~44주 생육하였다. 교목층의 평균 수령은 66년, 아교목층은 22.9년이었으며 종다양도는 0.5472~0.8646로 분석되었다. 동백섬의 식생관리 방향으로서 기존 관리된 동백나무림은 주기적인 관리를 유지하며 관리되지 않은 사스레피나무림은 사스레피나무를 제거하고 동백나무를 식재하는 관리를 제안하였다. 관리되지 않은 험준지 사스레피나무림은 동백나무경관 형성이 불가능 할 것으로 예측되어 상록활엽수림으로의 천이유도 방안을 제시하였다.

• 한국농림기상학회지
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• 제23권4호
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• pp.340-348
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• 2021

본 연구는 콩의 한발 스트레스 판별에 대하여 RGB 영상에 기반한 작물 생육 지수의 적용 가능성과 한계점을 구명하기 위해 수행되었다. RGB 영상에서 추출한 생육 지수들과 한발 스트레스에 반응하는 대표적인 표현형 지표들(군락 피복도, 엽면적, 엽록소 함량 등)과의 높은 상관관계를 통해 영상 기반 생육 진단 모델개발의 가능성을 확인할 수 있었다. 다만 판별의 정확도와 해상도를 개선시키기 위해서는 향후 다양한 재배조건에서 지속적인 성능 평가가 이루어져야 할 것이다. 본 연구의 결과는 향후 RGB 영상을 활용한 콩환경 스트레스 판별에 있어서 영상 전처리, 영상 분석방법, 생육 지수 정량화 기술 개발에 도움을 줄 수 있을 것이며, 개발된 생육 인자 예측 모델은 환경 스트레스 조기 진단을 통한 영농 의사결정 지원 모델의 개발에 기여할 수 있을 것으로 판단된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.250-255
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• 2002

This paper describes the study methods of identifying forest vegetation types, based on this study, forest vegetation classification method based on vegetation index is proposed. According to reflectance data of vegetation canopy and soil line equation NIR=1.506R+0.0076 in Jingyuetan, Changchun, China, many vegetation index are calculated and analyzed. The relationships between vegetation index and vegetation types are that PVI identifies broadleaf forest and conifer forest the most easily, the next is TSAVI and MSAVI, but their calculation is complex. RVI values of different conifer trees vary obviously, so RVI can classify conifer trees. In a word, combination of PVI and RVI is evaluated to classify different vegetation types.