• KIEAE Journal
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• v.12 no.5
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• pp.3-10
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• 2012

In this study, the influence of decentralized rainwater management over the changes in evapotranspiration was analyzed. The analysis method was obtained by establishing the decentralized rainwater management plan according to different scenarios, and subsequently examined evapotranspiration in the plan. Scenario 1 refers to the analysis of the existing situation, in which was 100% of a parking lot is asphalt pavement. In Scenario 2, the pavement of the parking surface in the parking lot is replaced with lawn blocks. In Scenario 3, some asphalt pavement was removed to establish a flower-bed type infiltration system to allow rainwater to permeate. In Scenario 4, infiltration and storage of rain water would be achieved by transforming the parking surface into lawn blocks, keeping the asphalt for the parking road while establishing a vegetation strip. The amount of evapotranspiration of the target site was analyzed with a water budget analysis program (CAT) using the 2001 meteorological data for each scenario According to the analysis values of S2 and S3, it was found that evapotranspiration is critically affected by the amount of area replaced with pervious area in the total target site. An energy equivalent to 680kWh is required for 1 ton of water to evaporate. Hence, it can be seen that the active inducement of evapotranspiration in urban area makes a positive contribution not only to heat island mitigation, but also to the small-scale water circulation process in a city.

• Journal of the Korean earth science society
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• v.27 no.6
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• pp.677-686
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• 2006

Surface evapotranspiration is one of the most important factors to determine the surface energy budget, and its estimation is strongly related with the accuracy of weather forecasting. Surface evapotranspiration over Daegu Metropolitan was estimated using high resolution LANDSAT TM data. The estimation of surface evapotranspiration is based on the relationship between surface radiative temperature and vegetation index provided by a TM sensor. The distribution of NDVI (Normalized Difference of Vegetation Index) corresponds well with that of land-used in Deagu Metropolitan. The temperature of several part of downtown in Deagu metropolitan is lower in comparison with the averaged radiative temperature. This is caused by the high evapotranspiration from dense vegetation like DooRyu Park in Deagu Metropolitan. But, weak evapotranspiration availability is distinguished over the central part of downtown and the difference of evapotranspiration availability on industrial complexes and residential area is also clear.

• Magazine of the Korean Society of Agricultural Engineers
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• v.25 no.2
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• pp.42-53
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• 1983

In Korea, the demand for water is increasing greatly due to Korea's raqid economic progress which is similar to Japan's. A correct estimation of the runoff factors is the question that must be settled first to establish the appropritae plans for water use and water resources. of these plans the estimation of catchment evapotranspiration for every river basin is the subject of the most importance. It is impossible theoretically to measure evapotranspiration directly, because it is an at mospheric translatory phenomenon. Many approaches have been devised to estimate evapotranspiration, but each of these methods estimates from information taken from a specified point, and these methods are considered incomplete for estimating catchment evapotranspiration. In this paper, the seasonal evapotranspiration estimating method that was proposed by Linsly and was applied in the Kamigamo exprimental basin (subjected to Kyoto Univ.) by Takase et al, was used for the Geum river which is the main river in Korea. Conclusion of experiment. 1) The average annual Ec in this river basin from 1966 to 1972 was 470mm. That is considered appropriate since the average value for the six other large river basin in korea was 485mm. 2) The Ec/Ep and Ec/Epm ratios were 0.43 and 0.52, respectively (Ec : estimated evapotranspiration by water balance method, Ep : average pan evaporation, Epm : evaporation by Penman method). The seasonal Ec/Ep ratios were : 0.4 in spring, 0.6 in summer, 0.4 in autumn and 0.2 in winter. These are rather small when compared to Japan's or England's. 3) The reason for this was that the precipitational difference in wet and dry seasons were greater, an there was not sufficient soil moisture harmonize with the evapotranspiration capacity in the dry season, and that evapotranspiration was small due to the numerous barren mountains.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.71-81
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• 2007

One of the most important hydrologic components is evapotranspiration. It is a process by which water is evaporated from moist land surfaces and transpired into atmosphere by plants. There are many methods of estimating evapotranspiration rate and its potential such as the methods of soil-moisture sampling, lysimeter measurements, water balance, energy balance, groundwater fluctuations and evapotranspiration. But it is very difficult to estimate evapotranspiration in terms of regional discrete characteristics of topography and/or vegetation. The evapotranspiration is strongly affected by ground covering vegetation, and the degree of vegetation growth. In order to grasp vegetation condition over a vast study area, NDVI (Normalized Difference Vegetation Indices) calculated from the data obtained from NOAA/AVHRR were utilized. Through multi-regression analysis, we developed a model equation to estimate the evapotranspiration using NDVIs and temperature data.

• Journal of Climate Change Research
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• v.9 no.2
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• pp.143-156
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• 2018

Evapotranspiration is a key element in designing and operating agricultural hydraulic structures. The profound effect of climate change to local agro-hydrological systems makes it inevitable to study the potential variability in evapotranspiration rate in order to develop policies on future agricultural water management as well as to evaluate changes in agricultural environment. The APEX-Paddy model was used to simulate local evapotranspiration responses to climate change scenarios. Nine Global Climate Models(GCMs) downscaled using a non-parametric quantile mapping method and a Multi?Model Ensemble method(MME) were used for an uncertainty analysis in the climate scenarios. Results indicate that APEX-Paddy and the downscaled 9 GCMs reproduce evapotranspiration accurately for historical period(1976~2005). For future periods, simulated evapotranspiration rate under the RCP 4.5 scenario showed increasing trends by -1.31%, 2.21% and 4.32% for 2025s(2011~2040), 2055s(2041~2070) and 2085s(2071~2100), respectively, compared with historical(441.6 mm). Similar trends were found under the RCP 8.5 scenario with the rates of increase by 0.00%, 4.67%, and 7.41% for the near?term, mid?term, and long?term periods. Monthly evapotranspiration was predicted to be the highest in August, July was the month having a strong upward trend while. September and October were the months showing downward trends in evapotranspiration are mainly resulted from the shortening of the growth period of paddy rice due to temperature increase and stomatal closer as ambient $CO_2$ concentration increases in the future.

• Journal of Climate Change Research
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• v.8 no.2
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• pp.125-143
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• 2017

This study is conducted to estimate potential evapotranspiration of 10 weather observing systems in Andong Dam watershed with FAO56 Penman-Monteith (FAO56 PM) methodology using the meteorological data from 2013 to 2014. Also, assuming that there is no solar radiation data, humidity data or wind speed data, the potential evapotranspiration was estimated by FAO56 PM and the results were evaluated to discuss whether the methodology is applicable when meteorological dataset is not available. Then, the potential evapotranspiration was estimated with Hargreaves method and compared with the potential evapotranspiration estimated by FAO56 PM only with the temperature dataset. As to compare the potential evapotranspiration estimated from the complete meteorological dataset and that estimated from limited dataset, statistical analysis was performed using the Root Mean Square Error (RMSE), the Mean Bias Error (MBE), the Mean Absolute Error (MAE) and the coefficient of determination ($R^2$). Also the Inverse Distance Weighted (IDW) method was performed to conduct spatial analysis. From the result, even when the meteorological data is limited, FAO56 PM showed relatively high accuracy in calculating potential evapotranspiration by estimating the meteorological data.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.193-199
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• 2000

In order to provide basic information for the estimation of reference crop evapotranspiration in the greenhouse, an lysimeter experiment was performed. Kenturky Blue Grass was used as a reference crop. Relationships between measured reference crop evapotranspiration and weather factors were analyzed. A multi-regression model was developed and tested.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.241-244
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• 2002

A formula of watershed evapotranspiration by Penman or Thonthwaite or Lowry-Johnson was used to measure its quantity of evapotranspiration until now. These formula were derived for Foreign country and, it is rather difficult to apply the above formulas to the Korean watershed. These measuring methods are merely used to measure the monthly quantities of evapotranspiration. At the research CE of a coefficient of evapotranspiration for a watershed were newly presented, which was utilized for the calculation of Beken's formula in the DAWAST model.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.135-141
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• 2018

The specification of surface vegetation is essential for simulating actual evapotranspiration of water resources. The availability of land cover maps based on remotely collected data makes the specification of surface vegetation easier. The spatial resolution of hydrologic models rarely matches the spatial scales of the vegetation data needed, and remotely collected vegetation data often are upscaled up to conform to the hydrologic model scale. In this study, the effects of the grid scale of of surface vegetation on the results of actual evapotranspiration were examined. The results show that the coarser resolution causes larger error in relative terms and that a more realistic description of area-averaged vegetation nature and characteristics needs to be considered when calculating actual evapotranspiration.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.15-24
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• 2004

The purpose of this study is to estimate monthly evapotranspiration (ET) using normalized difference vegetation index (NDVI) obtained from NOAA-AVHRR data sets. Actual evapotranspiration was evaluated by the complementary relationship, and monthly NDVI was obtained by maximum value composite method from daily NDVI images in the Korean peninsula for the year 2001 The monthly actual ETs for each land cover were compared with the monthly NDVIs to determine relationships between actual ET and NDVI for each land cover category, There was a high correlation between monthly NDVI and monthly mean actual ET. This study presents an alternative approach for land surface evapotranspiration based on remote sensing techniques.