검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 26

        21.
        2009.03 KCI 등재 서비스 종료(열람 제한)
        Hydraulic gradient of the landfill soils is estimated by Devlin (2003) method, and its variation characteristics from rainfall and permeability of the aquifer material are analyzed. The study site of 18 m × 12 m is located in front of the Environment Research Center at the Pukyong National University, and core logging, slug/bail test and groundwater monitoring was performed. The slug/bail tests were performed in 9 wells (except BH9 well), and drawdown data with elapsed time for bail tests were analyzed using Bouwer-Rice and Hvorslev methods. The average hydraulic conductivity estimated in each of the test wells was ranged 1.991 ×10-7~4.714×10-6 m/sec, and the average hydraulic conductivity in the study site was estimated 2.376×10-6 m/sec for arithmetic average, 1.655×10-6 m/sec for geometric average and 9.366×10-7 m/sec for harmonic average. The permeability of landfill soils was higher at the east side of the study site than at the west side. Groundwater level in 10 wells was monitored 44 times from October 2 to November 7, 2007. The groundwater level was ranged 1.187~1.610 m, and the average groundwater level range in each of the well showed 1.256~1.407 m. The groundwater level was higher at the east side than at the west side of the study site, and this distribution is identify to it of hydraulic conductivity. The hydraulic gradient and the major flow direction for 10 wells were estimated 0.0072~0.0093 and 81.7618~88.0836°, respectively. Also, the hydraulic gradient and the major flow direction for 9 wells were estimated 0.0102~0.0124 and 84.6822~89.1174°, respectively. The hydraulic gradient of the study site increased from rainfall (83.5 mm) on October 7, causing by that the groundwater level of the site with high permeability was higher. The hydraulic gradient estimated on and after October 16 was stable, due to almost no rainfall. Thus, it was confirmed that the variation of the hydraulic gradient in the landfill soils was controlled by the rainfall.
        22.
        2007.02 KCI 등재 서비스 종료(열람 제한)
        In the coastal wetland the mud is consist of fine particles, which means that it is characterized by small gap, and heat transfer is obstructed since moisture is found between the gaps. The relationship between net radiation() and soil heat flux() shows a counterclockwise hysteresis cycle, which refer to a time lag behind in the maximal soil heat fluxes. The albedo is independent of seasonal variation of the vegetation canopy which plays very important roles to store and control the heat in the atmospheric surface layer.
        23.
        2007.01 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to clarify the effect of mountain-valley wind on heat island formed in urban area which is located around valley mouth. The meteorological observations were carried out over the Dalbi-valley under a clear summer pressure patterns, and some consideration were tried from the results. In order to make clear the climatological characteristics and air-mass modification process of the mountain-valley wind over the valley, the meteorological observations were done simultaneously at two points. The observational points were located at the breast and valley mouth parts, respectively. The results were as follows: First, it was found that the valley wind was observed through the daytime, and it was replaced by a mountain wind after sunset. Second, the heat budget is also investigated with observation data. The sensible heat flux over the breast of Dalbi-valley reached to about 200during daytime, which is a little more than one third of net radiation. On the other hand, the sensible heat flux represented negative values during nighttime. But the sensible heat flux over the valley mouth covered by asphalt showed plus value(about 20~30) during the nighttime.
        24.
        2002.03 KCI 등재 서비스 종료(열람 제한)
        Using measured data at Daegu by tethersonde for the period of 1984~1987, we have investigated the lower atmospheric boundary layer structure including relationships between inversion layer and meteorological factors(wind and temperature), and the inversion strength and inversion height. The inversion layer was defined from the vertical temperature profile and its strength was analyzed with the wind shear as well as the vertical temperature gradient. From October to January, measured inversion layer isn't destroyed, however, in June, after sun rise, it is destroyed by surface heating and mixed layer is developed from surface. According to Pasquill stability classes, the moderately stable cases dominated. It's the larger vertical temperature gradient, the lower SBL height. We have introduced B(bulk turbulence scale) which indicated SBL height. It's larger B, the higher SBL height and vice versa. It was noted that the bulk turbulence scale (B) is appropriate to determine the stable boundary layer height.
        25.
        2001.10 KCI 등재 서비스 종료(열람 제한)
        The Rondonia Boundary Layer Experiment (RBLE-Ⅱ) was conceived to collect data the atmospheric boundary layer over two representative surfaces in the Amazon region of Brazil; tropical forest and a deforested, pasture area. The present study deals with the observations of atmospheric boundary layer growth and decay. Although the atmospheric boundary layer measurements made in RBLE-Ⅱ were not made simultaneously over the two different surface types, some insights can be gained from analysing and comparing with their structure. The greater depth of the nocturnal boundary layer at the forest site may be due to the influence of mechanical turbulence. The pasture site is aerodynamically smoother and so the downward turbulent diffusion will be much less, resulting in a lower surface temperature. The strength of thermal inversion is, consequently, higher over the pasture than over the forest. The development of the convective boundary layer is stronger over the pasture than over the forest. The influence of the sensible heat flux is important but may be not enough to explain the difference completely. It seems that energy advection may occur from the wet and colder (forest) to the dry and warmer area (pasture), rapidly breaking up the nocturnal inversion. Such advection can explain the abrupt growth of the convective boundary layer at the pasture site during the early morning.
        26.
        2001.10 KCI 등재 서비스 종료(열람 제한)
        Characgcteristics of nocturnal boundary layer (NBL) were analyzed by the upper-air observations data using with the airsonde and pilot balloons from 1994 to 1999 in Kyungpook province. The automatic weather system was also installed to obtain data in the surface layer. The atmospheric boundary layer can become stably stratified when the surface is cooler than the air. Stable nocturnal boundary layer heights were estimated from the top of surface stable layer where the vertical gradient of temperature and mixing ratio tend to zero or negative. The depth of the stable nocturnal boundary layer depended largely on the thermal effect rather than the wind effect at nighttime. The NBL was more developed on the land than on the coastal region. The stability index (bulk Richardson number) showed that the NBL was stable when the wind was weak and the vertical gradient of the temperature was strong. The heat budget in the NBL was studied by considering the effect of the radiative and the turbulent cooling rates in the cases with cloud and without cloud. The NBL under clear sky was cooled by both the longwave radiative flux and the divergence of the heat flux, while NBL under the cloudy sky the longwave radiative flux played a role of the warming. It was noted that the heat was not conserved in both cases. To complete the heat budget in the NBL the warming/cooling by advection and subsidence must be considered.
        1 2