• Title/Summary/Keyword: Radiation balance

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Validation of Net Radiation Measured from Fluxtower Based on Eddy Covariance Method: Case Study in Seolmacheon and Cheongmicheon Watersheds (에디공분산 방법 기반의 플럭스 타워 순 복사에너지 검증: 설마천, 청미천 유역)

  • Byun, Kyuhyun;Shin, Jiyae;Lee, Yeon-Kil;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.46 no.2
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    • pp.111-122
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    • 2013
  • The necessity of clear understanding of water and energy cycles has been attracted recently due to the climate change. The micrometeorological flux tower networks play a role of cornerstone of the hydrological and ecological analyses. Although the eddy covariance techniques used for flux tower have been proven to be applicable for estimation of latent heat flux, the raw data are often underestimated and needs to be corrected. Among several methods, the Bowen ratio is recognized as the most useful method in which the net radiation and other flux data (Ground heat flux, Sensible heat flux) are used and needed to be validated. In this study, in order to validate the net radiation from flux tower in Seolmacheon and Cheongmicheon watersheds, we compare it with two version of calculated net radiation: (1) FAO 56 Daily net radiation proposed by Allen et al. (1998). (2) Instantaneous net radiation proposed by Bastiaanssen (1995). The results showed that the net radiation from the flux data had similar tendency with those calculated based on physical theory. In addition, after it was applied to Bowen ratio method, the corrected latent heat flux was considerably improved with making the energy balance much more closed.

On the Warming Effects due to Artificial Constructions in a Large Housing Complex (대규모 주택단지내의 인공구조물에 의한 승온화효과에 관한 연구)

  • 김해동;이송옥;구현숙
    • Journal of Environmental Science International
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    • v.12 no.7
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    • pp.705-713
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    • 2003
  • In mid-August 2002, under clear summer pressure patterns, we carried out an intensive meteorological observation to examine the warming effects due to artificial constructions in a large housing complex. We set an automatic weather system(AWS) at two places in a bare soil surface within a limited development district and an asphalt surface within a large apartment residence area, respectively. As a result of observation, it became clear that the difference of the surface air(ground) temperature between the bare soil surface and its peripheral asphalt area reached about 4$^{\circ}C$(13$^{\circ}C$) at the maximum from diurnal variation of surface temperatures on AWS data. Through the heat balance analysis using measurement data, it became clear that the thermal conditions at two places are dependent on the properties of surface material. The latent heat flux over the bare soil surface reached to about 300 W/㎡, which is more than a half of net radiation during the daytime. On the other hand, it was nearly zero over the asphalt surface. Hence, the sensible heat flux over the asphalt surface was far more than that of the bare soil surface. The sensible heat flux over the asphalt surface showed about 20∼30 W/㎡ during the night. It was released from asphalt surface which have far more heat capacity than that of bare soil surface.

Estimation of Surface Runoff from Paddy Plots using an Artificial Neural Network (인공신경망 기법을 이용한 논에서의 지표 유출량 산정)

  • Ahn, Ji-Hyun;Kang, Moon-Seong;Song, In-Hong;Lee, Kyong-Do;Song, Jeong-Heon;Jang, Jeong-Ryeol
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.4
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    • pp.65-71
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    • 2012
  • The objective of this study was to estimate surface runoff from rice paddy plots using an artificial neural network (ANN). A field experiment with three treatment levels was conducted in the NICS saemangum experimental field located in Iksan, Korea. The ANN model with the optimal network architectures, named Paddy1901 with 19 input nodes, 1 hidden layer with 16 neurons nodes, and 1 output node, was adopted to predict surface runoff from the plots. The model consisted of 7 parameters of precipitation, irrigation rate, ponding depth, average temperature, relative humidity, wind speed, and solar radiation on the daily basis. Daily runoff, as the target simulation value, was computed using a water balance equation. The field data collected in 2011 were used for training and validation of the model. The model was trained based on the error back propagation algorithm with sigmoid activation function. Simulation results for the independent training and testing data series showed that the model can perform well in simulating surface runoff from the study plots. The developed model has a main advantage that there is no requirement for any prior assumptions regarding the processes involved. ANN model thus can be a good tool to predict surface runoff from rice paddy fields.

Flux of Carbon Dioxide and Deposition Velocity of Ozone over Glycine max Canopy (대두 개체군에 있어서 $CO_2$$O_3$ 플럭스)

  • 김원식;이호준
    • The Korean Journal of Ecology
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    • v.23 no.1
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    • pp.39-43
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    • 2000
  • Carbon dioxide (CO₂) and ozone (O₃) fluxes were measured over Glycine max canopy using the bowen ratio energy balance method at Fuchu - 20 km west of Tokyo, in late July and late September 1996. The CO₂, and O₃, fluxes were influenced by variation in leaf area index (LAI) during the measuring period. When LAI was more than 3.0, the CO₂ flux was found to be positively correlated with photosynthetically active radiation (PAR). The O₃, flux was always positive with an average deposition velocity for this case of about 0.5 mol m/sup -2/s/sup -1/. A positive correlation existed between the deposition velocity of O₃ and CO₂ during the period of LAI>2.0.

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A Fundamental Study of BIPV System Functioned as Solar Collector for Building Application (건물 적용을 위한 태양열 집열기 기능을 갖는 BIPV 시스템의 기초적 연구)

  • Min, Sung-Hye;Suh, Seung-Jik
    • Journal of the Korean Solar Energy Society
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    • v.27 no.1
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    • pp.91-98
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    • 2007
  • Perimeter zone is one of the weakest area in buildings and it makes an increase of heating and cooling loads, in addition to condensation or discomfort with cold-draft to residents in winter. Because of this, it needs to be reinforced by active systems. However, they use fossil fuel, and ultimately greenhouse effect is urged. Thus, we proposed BIPV system functioned as solar collector which can substitute active system. As an fundamental stage, heat balance equation in steady-state by Fortran was used not only, in winter for pre-heating effect and electric power capacity during the day, but also in summer, for the latter during the day and sky radiation effect during the night. Especially, we should have considered shading on PV by IES Suncast, since even a little bit of it makes the efficiency too low for the PV modules to work. As a result, in summer day, the PV panel should be tiled in 70 degrees to gain the most electric power. Moreover, we could verify that this model makes higher temperature and heat flux under 0.02 m/s. On the other hand, the PV had the high efficiency with high velocity because of cooling effect behind the PV. Therefore, we should regard the air current distribution later on.

Application of BIPV System Functioned as Solar Collector (태양열 집열기 기능을 갖는 BIPV 시스템의 응용)

  • Min, Sung-Hye;Suh, Seung-Jik
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.953-958
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    • 2006
  • Perimeter zone has been reinforced by active systems, such as fan-coil units, because it causes an increase in heating and cooling loads, dew condensation in winter, or discomfort with cold-draft to residents in buildings, through poor insulation by light-weighed skin due to progressing multi-storied buildings and skyscrapers. However, because these active systems raise Its capacity so that fossil fuel is used as much as they are added, and ultimately, greenhouse effect is urged, we proposed BIPV system functioned as solar collector which can substitute active system. As an early stage, heat balance equation in steady-state by Fortran was used not only for pre-heating effect and electric power capacity during the day in winter, but also for electric power capacity during day in slimmer and sky radiation effect during night in summer. Especially, we should have considered shading on PV, since even a little bit of it makes the efficiency too low for the PV to work. Still, when the flux of pre-heated air was increased to make air-barrier, its temperature was not enough to make it because the speed of heat exchange was too fast to warm up the air, thus the capacity to meet the condition was evaluated, and electric power from PV was made used for it.

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The Tendency Analysis of Albedo by Land Cover Over Northeast Asia Using MODIS 16-Day Composited Albedo data (MODIS 16-Day Albedo 자료를 이용한 동북아시아 지역의 토지피복 별 알베도 변화 분석)

  • Park, Eun-Bin;Han, Kyung-Soo;Lee, Chang-Suk;Pi, Kyung-Jin
    • Korean Journal of Remote Sensing
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    • v.28 no.5
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    • pp.501-508
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    • 2012
  • Albedo is known as a factor that directly impacts on the surface energy balance one of the elements of earth radiation balance. The change of albedo includes the change of soil moisture, vegetation, solar zenith angle, snow, and so on. In addition, it operates as a crucial path to understanding feedback mechanisms between radiation balance and its influence on climate and vegetation dynamics and therefore, observing the variation of albedo is a one of the essential procedures for anticipating climate change. In this study, we used MODIS 16-Day composited Albedo data from 2001 to 2011 years with the purpose of observing the change of albedo over Northeast Asia. According to the tendency of albedo for 11 years, albedo in the area of an active vegetation has increased in near-infrared (NIR) domain and decreased in visible (VIS) domain. On the basis of local changes in vegetation in 2002, the both area of the Gobi Desert and the Manchuria was enormously changed and chosen the research area and furthermore, the vegetation of both regions had deteriorated due to the change of the minimum value since 2010.

Developing a Model to Predict Road Surface Temperature using a Heat-Balance Method, Taking into Traffic Volume (교통량을 고려한 열수지법에 의한 노면온도 예측모형의 구축)

  • Son, Young-Tae;Jeon, Jin-Suk;Whang, Jun-Mun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.14 no.2
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    • pp.30-38
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    • 2015
  • In this study, to improve effectiveness of road management services and the safety of the road in winter, road surface temperature prediction model was developed. We have utilized the existing input data of meteorological data and additional traffic data. This Road surface temperature prediction model was utilizing a Heat-Balance Method additionally considering amount of traffic that produce heat radiation by vehicle-tire friction. This improved model was compared to the based model to check into influence of traffic affecting the road surface temperature. There were verified by comparing the real observed road surface temperature of the third Gyeong-In highway and road surface temperature from the two models. As a result, the error of real observed and the predicted value (RMSE) was found to average $1.97^{\circ}C$. Observed road surface temperature was dramatically affected by the sunlight from 6 a.m. to 2 p.m. and degree of influence decreases after that. The predictive value of the model is lower than the observed value in the afternoon, and higher at night. These results appear due to the shielding of solar radiation caused by the vehicle in the afternoon and at night, the vehicle appeared to cause thermal heat supply.

An Assessment of Areal Evaportranspiration Using Landsat TM Data (Landsat TM 자료를 이용한 광역 증발산량 추정)

  • Chae, Hyo-Seok;Song, Yeong-Su;Park, Jae-Yeong
    • Journal of Korea Water Resources Association
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    • v.33 no.4
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    • pp.471-482
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    • 2000
  • Surface energy balance components were evaluated by Landsat TM data and GIS with meteorological data. Calibration and validation for the applicability of this methodology were made through the estimating of the large-scale evapotranspiration (ET). In addition, sensitivity and error analysis was conducted to see the effects of the surface energy balance components on ET and the accuracy of each components. Bochong-chon located on the upper part of Guem River basin was selected as the case study area. Spatial distribution map of ET were produced for five dates: Jan. 1, Apr. 3, May. 10, and Nov. 27, 1995. The study results showed tat ET was greatly varied with the aspect and theland use type on the surface. In the case of having northeast and southeast in the aspect, ET was linearly increased depending on growing net radiation. While surface temperature has a high value, NDVI(Normalized Difference Vegetation Index) has a low value in the vegetated area. Therefore, ground heat flux was increased but ET was relatively decreased. The results of sensitivity and error analysis showed that net radiation is most sensitive and effective, ranging from 12.5% to 23.6% of sensitivity. Furthermore, the surface temperature, air temperature, and wind speed have the significant effects on ET estimation using remotely sensed data.

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An Outlook of the Oriental and Western Medical Diagnosis and Treatment on Large Bowel Cancer (대장암(大腸癌)의 동서의(東西醫) 결합(結合) 진치근황(診治近況))

  • Kim, Byeong-Ju;Moon, Goo
    • THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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    • v.5 no.1
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    • pp.1-17
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    • 1999
  • Large bowel cancer shows the 4-5th frequency in cancers that occurs in Korea. The western medicine cures the Large bowel cancer by radiation, surgery and chemotherapy. While, Oriental medicine cures the Large bowel cancer by Herb-drugs, acupuncture, moxa and et al. With just one way of treating Large bowel cancer can't be effective remedy. Because each medicine has a strength and weakness, it is effective treatment when two medicine combines and supplement each other. We got the following result about a trend of oriental and western combination treatment for Large bowel cancer through studding records. 1. In Large bowel cancer, colon cancer is referred hematochezia(腸風下血), rectal cancer is refereed enterotoxin(腸毒), and anal cancer is accumulation of pathogens in yin(結陰). 2. The western medicine treats Large bowel cancer patient with surgery first. They need on assembly treatment such as chemical, radiation and immune treatment. In oriental medicine, they treats Large bowel cancer patients with differentiation of symptom and signs and treatment(辨證施治) for example, insufficiency of spleen and stomach(脾胃虛弱), collapse of the spleen-ql(脾氣下陷), stagnation of blood stasis and toxic agent(瘀毒內結), reinforcing both qi and blood(脾血下陷), stagnation of damp-phlegm(痰濕凝結) and cure for them by acupuncture and moxa too. 3. In combination with oriental and western medical treatment princple of Large bowel cancer by each stage is as follows. First stage is cured with radical surgery and herb-drugs without chemotherapy. The intermediate and terminal stage patients is used radiation before surgery, or after palliative surgery cour with chemotherapy, radiation and Herb-drugs. In terminal stage patients, unable for surgery, is used combination between chemotherapy, palliative radiation and Herb-drugs. 4. After radiation surgery, the terminal stage patients who have extensively lymph node metastasis or local contraindication is able to undergo combination of Herb-durgs and chemotherapy. 5. The cure-effect with oriental and western medicine combination treatment was better than that just with oriental or western medical treatment. 6. The merits of oriental and western medicine combination treatment lengthen one's life and diminish the bad effect of chemotherapy and complete radiation treatment, prevent from relapsing, maintain the balance in their environment of body and improve immunity.

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