• Title/Summary/Keyword: sensible temperature

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Sensible heat flux estimated by gradient method at Goheung bay wetland (고흥만 습지에서 경도법으로 산출한 현열플럭스)

  • Kim, Dong-Su;Kwon, Byung-Hyuk;Kim, Il Kyu;Kang, Dong Hwan;Kim, Kwang-Ho;Kim, Geun-Hoi;Park, Jun-Sang
    • Journal of Fisheries and Marine Sciences Education
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    • v.20 no.2
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    • pp.156-167
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    • 2008
  • Meorological data have been collected to monitor the wetland area in Goheung bay since 2003 and four intensive observations were conducted to study effects of the atmospheric turbulence on the energy budget and the ecological changes. We improved an algorithm to estimate the sensible heat flux with routine data. The sensible heat flux estimated by gradient method was in good agreement with that measured by precision instruments such as surface layer scintillometer and ultrasonic anemometer. Diurnal variations of sensible heat flux showed analogous tendency to those of temperature gradient. When the vertical wind shear of horizontal wind components was weak, even though temperature gradient was strong, the gradient method underestimated the sensible heat flux. A compensation for the cloud will make this gradient method be a helpful tool to monitor the ecosystem without expensive instruments except for weak wind shear and temperature gradient.

Estimation of Daytime Sensible Heat Flux using Routine Meteorological Data (정규기상관측자료를 이용한 주간의 현열 플럭스 추정)

  • 이종범;김용국;박철용
    • Journal of Environmental Science International
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    • v.9 no.2
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    • pp.109-114
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    • 2000
  • The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.

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Simulation and Cost Estimation of Energy Transportation at Ambient Temperature Using an Absorption System (흡수식을 이용한 상온에너지수송의 모사 및 비용평가)

  • 김성수;오민규;전상현;강용태
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.12
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    • pp.1028-1034
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    • 2003
  • The objectives of this paper are to study the effect of key parameters on the cycle performance and capacity and to estimate the cost of latent and sensible energy transportation systems. The overall conductance (UA) of each component, the ambient temperature and the absorber inlet temperature are considered the key parameters. It is concluded that COP of the solution transportation using an absorption system (STA) at ambient temperature is 10% higher than that of the conventional sensible system. It is also found that the cost of STA system can be reduced 7.5 times to that of sensible energy transportation for one year of operation with 10 km transportation distance.

Characteristics of Sensible Heat and Latent Heat Fluxes over the East Sea Related with Yeongdong Heavy Snowfall Events (영동대설 사례와 관련된 동해상의 현열속과 잠열속 분포 특성)

  • Kim, Ji-Eon;Kwon, Tae-Yong;Lee, Bang-Yong
    • Ocean and Polar Research
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    • v.27 no.3
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    • pp.237-250
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    • 2005
  • To investigate the air mass modification related with Yeongdong Heavy snowfall events, we examined sensible and latent heat fluxes on the East Sea, the energy exchange between atmosphere and ocean in this study. Sensible and latent heats were calculated by a bulk aerodynamic method, in which NCEP/NCAR reanalysis data and NOAA/AVHRR weekly SST data with high resolution were used. Among winter precipitation events in the Yeongdong region, 19 heavy precipitation events $(1995{\sim}2001)$ were selected and classified into three types (mountain, cold-coastal, and warm types). Mountain-type precipitation shows highly positive anomalies of sensible and latent heats over the southwestern part of the East Set When separating them into the two components due to variability of wind and temperature/ specific Humidity, it is shown that the wind components are dominant. Cold-coastal-type precipitation also shows strong positive anomalies of sensible and latent heats over the northern part and over the central-northern part of the East Sea, respectively. It is shown that the sensible heat anomalies are caused mostly by the decrease of surface air temperature. So it can be explained that cold-coastal-type precipitation is closely related with the air mass modification due to cold air advection over warm ocean surface. But in warm-type precipitation, negative anomalies are found in the sensible and latent heat distributions. From this result, it may be postulated that warm-type precipitation is affected by the internal process of the atmosphere rather than the atmosphere-ocean interaction.

SATELLITE-DERIVED SENSIBLE HEAT FLUX OVER THE OCEAN

  • .Kubota Masahisa;Ohnishi Keisuke;Iwasaki Shinsuke;Tomita Hiroyuki
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.30-33
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    • 2005
  • Though sensible heat flux is one of heat flux components, it is generally considered that the importance is low compared with other components because of the small value. Actually sensible heat flux over the tropical ocean is extremely small, less than $100\;W/m^2$ .. However, it should be noted that sensible heat flux in boreal winter over the western boundary current regions is considerably large, about $100\;W/m^2$, and not neglected. In this study we carry out intercomparison of various global sensible heat flux data including not only satellite-derived data but also reanalysis data in order to clarify the characteristics of those data.

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Characteristic of air-side sensible heat transfer and pressure drop on the corrugate fin tube heat exchangers (Corrugate 휜-관 현열 열교환기의 구조에 따른 공기측 열전달 및 압력손실 특성)

  • Ryu, Joon-Il;Jeon, Chang-Duk;Lee, Jin-Ho;Nam, Leem-Woo
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.216-221
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    • 2007
  • An experiment was carried out to investigate the effect of a coolant circuit arrangement on the heat transfer and air pressure drop of a fin-tube sensible heat exchanger with the corrugated fin surface. The air inlet temperature was set to $23^{\circ}C$,the relative humidity to 50% and the air inlet flow rate to 20, 22, $25m^3/min$, respectively. while the coolant temperature was set to $7^{\circ}C$, and the coolant mass flow rate to 10, 16, 22kg/min, respectively. Experiment showed that the exchanger having a diameter of 12.7mm with parallel circuit does better performance in sensible heat transfer and air pressure drop than those three of diameter of 12.7mm with a series circuit and that with diameter of 15.88mm with a parallel circuit.

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Construction and Case Analysis of Detailed Urban Characteristic Information on Seoul Metropolitan Area for High-Resolution Numerical Weather Prediction Model (고해상도 수치예보모델을 위한 수도권지역의 상세한 도시특성정보 구축 및 사례 분석)

  • Lee, Hankyung;Jee, Joon-Bum;Yi, Chaeyeon;Min, Jae-Sik
    • Atmosphere
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    • v.29 no.5
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    • pp.567-583
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    • 2019
  • In this study, the high-resolution numerical simulations considering detailed anthropogenic heat, albedo, emission and roughness length are analyzed by using single layer Urban Canopy Model (UCM) in Weather Research Forecast (WRF). For this, improved urban parameter data for Seoul Metropolitan Area (SMA) was collected from global data. And then the parameters were applied to WRF-UCM model after it was processed into 2-dimensional topographical data. The 6 experiments were simulated by using the model with each parameter and verified against observation from Automated Weather Station (AWS) and flux tower for the temperature and sensible heat flux. The data for sensible heat flux of flux towers on Jungnang and Bucheon, the temperature of AWS on Jungnang, Gangnam, Bucheon and Neonggok were used as verification data. In the case of summer, the improvement of simulation by using detailed anthropogenic heat was higher than the other experiments in sensible flux simulation. The results of winter case show improved in all simulations using each advanced parameters in temperature and sensible heat flux simulation. Improvement of urban parameters in this study are possible to reflect the heat characteristics of urban area. Especially, detailed application of anthropogenic heat contributed to the enhancement of predicted value for sensible heat flux and temperature.

A Study on the Climatic Classification of Korea by the Sensible Degree (체감도에 의한 우리나라의 기후구분에 관한 연구)

  • 설동일;민병은
    • Journal of the Korean Institute of Navigation
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    • v.17 no.4
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    • pp.43-51
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    • 1993
  • The purposes of this study are to make an analysis the sensible degree in Korea by using the formulas prepared by Watanabe, and to divide the climatic classification by the sensible degree in order to apply in practical life. Most data(air temperature, relative humidity, wind velocity, atmospheric pressure) are extracted from the "Climatic Table of Korea, Volume II(1961~1990)" issued by the Korea Meteorological Administration. As a result of this study, distribution patterns of the sensible degree are similar to isotherms when the wind velocity is zero, and then the sensible degrees are reduced with the increase of latitude. And western coastal and inland regions have larger values than eastern coastal regions in summer. However, the cont-rary distributions are shown in winter. When the wind velocity is not zero, distribution patterns of the sensible degree are influenced by the wind velocity. In summer, the values of central and southern inland regions are especially higher than the coastal regions, and most northern districts and some inland regions (Kangnung, Ulchin, Yongju etc.) have low values in winter. Then, the climate of Korea is divided into four patterns as follows : Yow means the sensible degree when the wind velocity is zero in winter. Yow > 3 : Jeju Island and southern coastal regions Yow = 0~3 : Most southern district and eastern coastal regions of central districts Yow = -3~0 : Most central districts and some eastern coastal regions (Hamheung, Youngheung, Won-san etc.) of northern districts Yow < -3 : Most northern districts and some inland regions(Inje, Hongcheon, Yang-pyeong etc.) of cent-ral districts.districts.

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Vertical Structure of the Coastal Atmospheric Boundary Layer Based on Terra/MODIS Data (Terra/MODIS 자료를 이용한 연안 대기경계층의 연직구조)

  • Kim, Dong Su;Kwon, Byung Hyuk
    • Atmosphere
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    • v.17 no.3
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    • pp.281-289
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    • 2007
  • Micrometeorlogical and upper air observation have been conducted in order to determine the atmospheric boundary layer depth based on data from satellite and automatic weather systems. Terra/MODIS temperature profiles and sensible heat fluxes from the gradient method were used to estimate the mixed layer height over a coastal region. Results of the integral model were in good agreement with the mixed layer height observed using GPS radiosonde at Wolsung ($35.72^{\circ}N$, $129.48^{\circ}E$). Since the variation of the mixed layer height depends on the surface sensible heat flux, the integral model estimated properly the mixed layer height in the daytime. The buoyant heat flux, which is more important than the sensible heat flux in the coastal region, must be taken into consideration to improve the integral model. The vertical structure of atmospheric boundary layer can be analyzed only with the routine data and the satellite data.

Performance Analysis of Sensible and Latent Energy Recovery System for Thermally Controlled Facilities (향온시설물에 대한 현열 및 잠열 에너지 회수시스템의 성능해석)

  • 박병규;김무근;김근오
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.12
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    • pp.1057-1065
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    • 2000
  • A sizing of sensible and latent energy recovery system with condensing heat exchanger is important to the design of a thermally controlled facilities. The transient system simulation program TRNSYS 14.2/IISiBat has been used to evaluate the energy consumptions of a thermally controlled facilities which consist of boiler, chiller and condensing heat exchanger, The boiler and chiller are selected based on the annual peak loads and controlled to maintain the setting temperature of $14~17^{\circ}C$. Simulation shows that the amount of sensible and latent energy recovered by heat exchanger is almost 20% of total heating load.

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