• 한국환경과학회지
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• 제6권6호
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• pp.579-588
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• 1997

In order to see the stratification related to the heat flux In Deukryang Bay, the oceanographic data on July 12, 1994 and the meteorological data of Kohung and Kwangju meteorological stations were analysed. The temperature durerences between the sea surface and the near bottom were 1~3 ton spring tide (July 12, 1994) In Deukryang Bay. The temperature anomalies were high about 3t during summer In 1994. These mean that the non mixing was not effective In destroying the stratification due to the sea surface heating by the solar radition, even though it was on spring tide. The maximum solar radiation was about 600 ly/day, which was the value of the same date of oceanographic observation. The sensible and the latent heat flux which are 0~100 ly/day were not so varied during summer. The absorbed heat flux through the sea surface was mostly lost by the back radiation. which ranges are about 0~-400 ly/day. The dimensionless mixing parameter related to the buoyancy flux was 5~150$\times$$10^{-5}$. The efficiency of tidal mixing to destroy the stratecation was 0.4~0.6%.

• Journal of Welding and Joining
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• 제11권2호
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• pp.13-20
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• 1993

The object of the research is to develop the flux for aluminum brazing. Five kinds of flux were applied to brazing joint with fin and tube structure using same filler metal. To estimate the performance of the developed flux, products analysis, differential thermal test, grain size test, observation of crystalline structure, tensile test, corrosion test were made. From the results of experiment, the following conculsions were obtained. 1. The optimum composition ratio (Wt) of AlF$_3$ and KF was 50-60% : 40-50% 2. The optimum melting point of the flux was 567-578$^{\circ}C$.

• 한국환경과학회지
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• 제9권2호
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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.

• Ocean and Polar Research
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• 제39권3호
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• pp.181-194
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• 2017

The long-term linear trend of global sea-to-air dimethyl sulfide (DMS) flux was analyzed over a 16-year time span (2000~2015), based on satellite observation data. The emission rates of DMS (i.e. DMS flux) in the global ocean were estimated from sea surface DMS concentrations, which were constructed with chlorophyll a (Chl-a) concentrations and mixed layer depths (MLD), and transfer velocity from sea to air, which was parameterized with sea surface wind (SSW) and sea surface temperature (SST). In general, the DMS flux in the global ocean exhibited a gradual decreasing pattern from 2000 (a total of 12.1 Tg/yr) to 2015 (10.7 Tg/yr). For the latitude band ($10^{\circ}$ interval between $0^{\circ}$ and $60^{\circ}$), the DMS flux at the low latitude of the Northern (NH) and Southern hemisphere (SH) was significantly higher than that at the middle latitude. The seasonal mean DMS flux was highest in winter followed by in summer in both hemispheres. From the long-term analysis with the Mann-Kendall (MK) statistical test, a clear downward trend of DMS flux was predicted to be broad over the global ocean during the study period (NH: $-0.001{\sim}-0.036{\mu}mol/m^2/day\;per\;year$, SH: $-0.011{\sim}-0.051{\mu}mol/m^2/day\;per\;year$). These trend values were statistically significant (p < 0.05) for most of the latitude bands. The magnitude of the downward trend of DMS flux at the low latitude in the NH was somewhat higher than that at the middle latitude during most seasons, and vice versa for the SH. The spatio-temporal characteristics of DMS flux and its long-term trend were likely to be primarily affected not only by the SSW (high positive correlation of r = 0.687) but also in part by the SST (r = 0.685).

• 한국환경과학회지
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• 제12권7호
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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.

• 천문학회보
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• 제41권1호
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• pp.73.2-73.2
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• 2016

We present the results of KaVA SgrA* observation together with Takahagi(32m), Yamaguchi(32m) and Nobeyama(45m) telescopes at 22 and 43GHz, respectively. In early 2014, G2 cloud was expected to encounter with SgrA* and to make a significant flux variation, but it has not been measured yet. So it's worth to check our amplitude calibration method to confirm if we have a missing flux caused by uncertainty in measuring it. We have tested both a standard method using system noise temperature(Tsys) with antenna gain information, and a template method in order to calibrate antenna gain using nearby maser source. As a result, we found that the latter method is useful for antennas which have inaccurate gain information or poor Tsys measurements, and is especially effective for sources at low elevation like SgrA*. In addition, the comparison shows that the amplitude calibration by standard method can be improved up to 10% with a correction factor using a template method. This result implies we can get more accurate flux from a standard method when any maser source not exists around target.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1992년도 한국우주과학회보 제1권1호
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• pp.12-12
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• 1992

Results from the Earth Radiation Budget Experiment (ERBE) will help interpret the data from the operational satellite system. However, a major problem exists because a follow-on experiment to ERBE is not planned until the late 1990`s. Meanwhile, it will be necessary to provide OLR estimates from the operational satellite system. Since 1973the outgoing long wave radiation(OLR) data have been obtained by the 10#m window radiance(AVHRR) estimation technique from he observation NOAA operational satellites. However, those data have not been universall if accepted because they are estimated from the radiance in but one narrow spectral regiou. However , this type of technique has not been exploited for use with data from the ]fIRS multispectral radiometer. Since the radiance data measured by HIRS contains more: information on atmospheric variables than the AVHRR, it is a potentially better instrument for operational estimates of the OLR In this study, results from model are better flux estimates than the AVHRR, The technique is then tested by comparing simultalleous AVHRR and HIRS OLR estimations with a radiation model flux calculation froml homogeneous atmospheric scenes at the regions of desert and subtropic ocean.

• 대기
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• 제17권3호
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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.

• 한국대기환경학회지
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• 제14권5호
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• pp.465-478
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• 1998

In this study, seasonal variations of the dry deposition velocity and deposition flux for the sulfur dioxide were analysed. The field observation was performed during one year (from November 1, 1995 to October 31, 1996) in Chunchon basin. The turbulence data were measured by 3-dimensional sonic anemometer/thermometer, and were estimated by mean meteorological data obtained at two heights (2.5 m and 10 m) of meteorological tower. Also, the estimation methods were evaluated by comparing the turbulence data. The results showed that the estimated dry deposition velocity and turbulence parameter such as uc and sensible heat flux using mean meteorological data were relatively similar to the sonic measurements, but all showed somewhat large differences. The dry deposition velocity was large in summer and small in winter mainly due to canopy resistance (rc). The major factor which affects diurnal variation of the velocity was aerodynamic resistance (rw). The SO2 dry deposition flux was large in winter and small in summer in Chunchon.

• 천문학회보
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• 제43권1호
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• pp.49.2-49.2
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• 2018

Flux calibration for narrow band photometric data gives us an opportunity to get a line flux of extended targets. We developed flux calibration processes for narrow band photometry using broad band filters as a continuum indicator. We derived parameters for color correction and zero point correction including color terms. Applying our method, we successfully subtracted continuum emissions and calibrated the emission lines from an FU Ori type object, V960 Mon.