• Proceedings of the KSRS Conference
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• v.2
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• pp.752-755
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• 2006

Evaportranspiration is an important factor in hydrology cycle. Traditionally, it is measured by using basin or empirical formula with meteorology data, while it does not represent the evaportranspiration over a regional area. With the advent of improved remote sensing technology, it becomes a surface parameter of research interest in the field of remote sensing. Airborne and satellite imagery are utilized in this study. The high resolution airborne images include visible, near infrared, and thermal infrared bands and the satellite images are acquired by MODIS. Surface heat fluxes such as latent heat flux and sensible heat flux are estimate by using airborne and satellite images with surface meteorological measurements. We develop a new method to estimate the evaportranspiration over the rice paddy. The surface heat fluxes are initialized with a surface energy balance concept and iterated for convergent solution with atmospheric correct functions associated with aerodynamic resistance of heat transport. Furthermore, we redistribute the total net energy into sensible heat and latent heat fluxes. The result reveals that radiation and evaporation controlled extremes can be properly decided with both airborne and satellite images. The correlation coefficient of latent heat flux and sensible heat flux with corresponding in situ observations are 0.66 and 0.76, respectively. The relative root mean squared errors (RMSEs) for latent heat flux and sensible heat flux are 97.81 $(W/m^2)$ and 124.33 $(W/m^2)$, respectively. It is also shown that the newly developed retrieval scheme performs well when it is tested by using MODIS date.

• Journal of the Korean earth science society
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• v.22 no.1
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• pp.40-46
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• 2001

Heat exchange between the atmosphere and sea is produced using the data from two 3m discus buoy installed by KMA in 1996. The meteorological and oceanic characteristics at the Dukjukdo and Chilbaldo buoy for the period 1996 ${\sim}$ 2000 are discussed. Daily averaged sensible heat and latent heat flux at each site are estimated from bulk aerodynamic method using given data and analyzed. Quantitative analyses show SST indicates 1-year cycle like air temperature but has 1 month lag. Sea level pressure is lowest in July, humidity is higher from May to August, and wind speed has averaged value of 5 m/s and higher in autumn and winter. Sensible heat flux analyses present that strong heat loss from the sea occurs in autumn and winter and weak heat loss from atmosphere appears in spring and summer, and net sensible heat loss from the sea is found throughout the year. The ocean significantly releases latent heat into atmosphere from August to May but get a little latent heat from atmosphere in other months. Net latent heat loss from the sea is larger than net sensible heat loss except in January and February. Comparison with two sites suggests that the magnitude of heat flux and their fluctuation are generally stronger at Dukjukdo than at Chilbaldo. In case study, both sensible and latent heat flux is a little more at Chilbaldo in March 1998, but substantially stronger at Dukjukdo in November 1996.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.3
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• pp.404-412
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• 2005

The surface energy budget depends on many factors, such as the type of surface, the soil moisture and the vegetation canopy, the geographical location, daily, monthly and seasonal variations, and weather conditions. In the coastal region, the surface is not homogeneous at various scales for instance water, sand, mud, tall grass, and crops. The energy balance over the vegetation canopy was analyzed with the optical energy balance measuring system. The latent heat flux was more intensive than the sensible heat flux. The sensible heat flux was very small in summer due to the canopy effect and higher in spring and autumn. In summer the development of the atmospheric boundary depended on rather the vertical shear of wind than the sensible heat flux.

• Atmosphere
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• v.34 no.1
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• pp.69-81
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• 2024

In this paper, Annual flux variations in the Boseong Tall Tower (BTT) from 2016 to 2020 were analyzed using data from three levels (2.5 m, 60 m, and 300 m). BTT was installed in Boseong-gun, Jeollanam-do in February 2014 and continued to conduct energy exchange observations such as CO2, sensible heat, and latent heat using the eddy covariance method until March 2023. The BTT was located in a very flat and uniform paddy field, and flux observations were conducted at four levels: 2.5 m, 60 m, 140 m, and 300 m above ground. Surface energy balance was confirmed from observed data of net radiation flux, soil heat flux, sensible heat flux, and latent heat flux. Additionally, 2.5 m height surface fluxes, which are most influenced by agricultural land, were compared with data from Local Data Assimilation and Prediction System (LDAPS) of the Korea Meteorological Administration to evaluate the accuracy of LDAPS flux data. The correlation coefficient between LDAPS flux data and observed values was 0.95 or higher. Excluding summer latent heat flux data, there was a general tendency for LDAPS data to be higher than observed values. The footprint areas estimated below 60 m height mainly covered agricultural land, and flux observations at 2.5 m and 60 m heights showed typical agricultural characteristics. In contrast, the footprint estimated at 300 m height did not show agricultural characteristics, indicating that observations at this height encompassed a wide range, including mountains, sea, and roads. The analysis results of long-term flux observations can contribute to understanding the energy and carbon dioxide fluxes in agricultural fields. Furthermore, these results can be utilized as essential data for validating and improving numerical models related to such fluxes.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1057-1063
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• 2016

The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.4
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• pp.206-213
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• 2004

Cycle test for developed phase change material (PCM) is necessary in order to assess the variation of latent heat, which decreases with time by deterioration. T-history method and measurement using heat-flux meter are appropriate for the cycle test in a tube filled with PCM because they do not need an extraction of sample in measuring heat of fusion. In the present study, these methods were applied to a PCM having a melting point below a room temperature, different to the past studies for PCMs melting above a room temperature. As a result of experiment using pure water as specimen, we can obtained rea-sonable values for heat of fusion.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.7
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• pp.604-610
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• 2003

Cycle test for developed phase change material (PCM) is necessary in order to analyze the variation of latent heat, which decreases with time by deterioration. 7-history method and measurement using heat flux meter are appropriate for the cycle test in a tube filled with PCM because they do not need an extraction of sample in measuring the heat of fusion. In the present study, these methods were applied to a PCM having a melting point below a room temperature, different from the past studies for PCMs melting above a room temperature. As a result of experiment using pure water as specimen, we can obtain reason-able values for heat of fusion by both methods.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.231-236
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• 1999

Accurate ocean surface fluxes with high resolution are critical for understanding a mechanism of global climate. However, it is difficult to derive those fluxes by using ocean observation data because the number of ocean observation data is extremely small and the distribution is inhomogeneous. On the other hand. satellite data are characterized by the high density, the high resolution and the homogeneity. Therefore, it can be considered that we obtain accurate ocean surface by using satellite data. Recently we constructed ocean surface data sets mainly using satellite data. The data set is named by Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO). Here, we introduce J-OFURO. The data set includes shortwave radiation, longwave radiation, latent heat flux, sensible heat flux, and momentum flux etc. Moreover, sea surface dynamic topography data are included in the data set. Radiation data sets covers western Pacific and eastern Indian Ocean because we use a Japanese geostationally satellite (GMS) to estimate radiation fluxes. On the other hand, turbulent heat fluxes are globally estimated. The constructed data sets are used and shows the effectiveness for many scientific studies.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.68-71
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• 2008

Our goal is to obtain a better scientific understanding how to define the nature and role of remotely sensed land surface parameters and energy fluxes in the heat island phenomena, and local and regional weather and climate. By using the MODIS visible and thermal imagery data and analyzing the surface energy flux images associated with the change of the landcover and landuse in study area, we will estimate and present how significant is the magnitude of the heat island heat effect and its relation with the surface parameters and the energy fluxes in Taiwan. To achieve our objective, we used the energy budget components such as net radiation, soil heat flux, sensible heat flux, and latent heat flux in the study area of interest derived form remotely sensed data to understand the island heat effect. The result shows that the water is the most important component to decrease the temperature, and the more the consumed net radiation to latent heat, the lower urban surface temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.6
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• pp.518-525
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• 2006

The present experiments have been performed for obtaining the melting heat transfer characteristics of micro-encapsulated solid-liquid phase-change material and water mixture slurry flow in a circular tube heated with constant wall heat flux. The phase change material having a low melting point was selected for a domestic cooling system in the present study. The governing parameters were found to be latent heat material concentration, heat flux, and the slurry velocity. The experimental results revealed that the increase of tube wall temperature of latent microcapsule slurry was lower than that of water caused by the heat absorption of fusion.