검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 77

        61.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        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.
        62.
        2015.11 KCI 등재 서비스 종료(열람 제한)
        In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.
        63.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        Seasonal and stational variation of SS and COD were investigated from February 2008 to December 2010 and the relationship between them was discussed. During three years monitoring, SS decreased significantly (46% decline) possibly due to the increase of precipitation and thereby resulting salinity drop. COD on average was the highest in 2009. SS was the highest in autumn and the lowest in winter, and over 72% of SS was FSS. While SS is high in the upper sampling stations of the bay with shallow water, COD values do not show any relationship to the geomorphological characteristics. CODins, which was defined as COD after filtration, ranged 56%(winter) ~ 44.6%(summer) and showed no correlation with SS. It indicates that high SS concentration is not necessarily related to the high CODins. The seasonal CODins/SS data, which can be interpreted as COD density in SS, shows that SS in winter contains the dense COD materials compared to the other seasons.
        64.
        2013.11 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to investigate the seasonal variation characteristics of phytoncide in trail of Ulsan Metropolitan. Air samples were collected from May to December 2011. They were collected using Tenax Ta tube and phytoncides were detected and quantified using a Gas Chromatograph Mass Spectrometer (GC/MSD). This study are summarized as follows; The seasonal concentrations of phytoncide are Munsu Mt. 272.3 ㎍/㎥, Samho Mt. 192.4 ㎍/㎥, Shinbul Mt. 50.9 ㎍/㎥, Sibli Bamboo forest 22.4 ㎍/㎥ and Joongbu Fire Station 24.4 ㎍/㎥. In Munsu Mt., Samho Mt. and Shinbul Mt. major component ratio is α-Pinene >β-Pinene+Myrcene >Limonene >Camphene >γ-Terpinene >α-Terpinene. Bamboo forest and Joongbu fire station major component ratio is α-Pinene >Limonene >β-Pinene+Myrcene >Camphene >α-Terpinene. The variation of seasonal concentration is summer >spring >fall >winter. The phytoncide concentration of coniferous forest(Munsu Mt., Samho Mt.) is higher than broadleaf forest(Shinbul Mt.).
        65.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The geomagnetic activity shows the semiannual variation stronger in vernal and autumnal equinoxes than in summer and winter solstices. The semiannual variation has been explained by three main hypotheses such as Axial hypothesis, Equinoctial hypothesis, and Russell-McPherron Effect. Many studies using the various geomagnetic indices have done to support three main hypotheses. In recent, Oh & Yi (2011) examined the solar magnetic polarity dependency of the geomagnetic storm occurrence defined by Dst index. They reported that there is no dependency of the semiannual variation on the sign of the solar polar fields. This study examines the solar magnetic polarity dependency of quiet time geomagnetic activity. Using Dxt index (Karinen & Mursula 2005) and Dcx index (Mursula & Karinen 2005) which are recently suggested, in addition to Dst index, we analyze the data of three-year at each solar minimum for eight solar cycles since 1932. As a result, the geomagnetic activity is stronger in the period that the solar magnetic polarity is anti-parallel with the Earth’s magnetic polarity. There exists the difference between vernal and autumnal equinoxes regarding the solar magnetic polarity dependency. However, the difference is not statistically significant. Thus, we conclude that there is no solar magnetic polarity dependency of the semiannual variation for quiet time geomagnetic activity.
        66.
        2012.03 KCI 등재 서비스 종료(열람 제한)
        Three embankments, namely Changpo, Bokkil and Guil, in Chunggye Bay were investigated to assess the influence of environmental changes to phytoplankton size structure, distribution of species and standing crops. Three stations was sampled near at each embankment in Nov. 2006, Feb. 2007, May 2007 and Aug. Phytoplankton were classified into net-size (>20㎛) and nano-size (<20㎛). In summer, the freshwater discharge seemed to have influence in the decrease of salinity and in the increase of turbidity, ammonium and phosphorus concentrations. Chl a concentration and phytoplankton abundance in Feb. 2007 were observed to be generally higher in all stations compared to other periods. Net-size phytoplankton was observed to be higher in Feb. 2007 and May 2007 compared to nano-sized phytoplankton. However, there was shift in phytoplankton composition in Nov. 2006 and Aug. 2007. Phytoplankton under seven class (Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae) was identified during the study period. It was found out that the major phytoplankton class was Bacillariophyceae. Phytoplankton was more diverse in autumn compared to any other season. Cyanophyceae was increased in summer. In rainy season, change in physical factors (salinity, transparency) seemed to have more influence on phytoplankton growth compared to inorganic nutrients.
        67.
        2012.02 KCI 등재 서비스 종료(열람 제한)
        The seasonal variations of ozone (O3) concentrations were investigated with regard to the relationship between O3 and wind distributions at two different sites (Jung Ang (JA): a semi-closed topography and Seo Chang (SC): a closed topography) within a valley city (Yangsan) and their comparison between these sites (JA and SC) and two non-valley sites (Dae Jeo (DJ) and Sang Nam (SN)) located downwind from coastal cities (Busan and Ulsan). This analysis was performed using the data sets of hourly O3 concentrations, meteorological factors (especially, wind speed and direction), and those on high O3 days exceeding the 8-h standard (60 ppb) during 2008-2009. In summer and fall (especially in June and October), the monthly mean values of the daily maximum O3 concentrations and the number of high O3 days at JA (and SC) were relatively higher than those at DJ (and SN). The increase in daytime O3 concentrations at JA in June was likely to be primarily impacted by the transport of O3 and its precursors from the coastal emission sources in Busan along the dominant southwesterly winds (about 5 m/s) under the penetration of sea breeze condition, compared to other months and sites. Such a phenomenon at SC in October was likely to be mainly caused by the accumulation of O3 and its precursors due to the relatively weak winds under the localized stagnant weather condition rather than the contribution of regional transport from the emission sources in Busan and Ulsan.
        68.
        2011.09 KCI 등재 서비스 종료(열람 제한)
        The three-dimensional hydrodynamic model was simulated to understand coastal sea front of formation and seasonal variation in the Southern Sea of Korea. In this study, we used to concept of stratification factor, to realize seasonal distribution of stratification coefficient which of seasonal residual flow, considered with, tide, wind and density effect. Tidal current tends to flow westward during the flood and eastward during ebb. The current by the wind stress showed to be much stronger the coastal than the offshore area in the surface layer. And the current by the horizontal gradient of water density showed to be relatively weak in the coastal area, with little seasonal differences. On the other hand, the flow in the offshore area showed results similar to that of the Tsushima Warm Current. The stratification factor (SHv) was calculated by taking into account the total flow of tide, wind and density effect. In summer, the calculated SHv distribution ranged from 2.0 to 2.5, similar to that of the coastal sea front. The horizontal temperature gradient showed to be strong during the winter, when the vertical stratification is weak. On the other hand, the horizontal gradient became weak in summer, during which vertical stratification is strong. Therefore, it is presume that the strength of vertical stratification and the horizontal temperature gradient affect the position of the coastal sea front.
        69.
        2010.01 KCI 등재 서비스 종료(열람 제한)
        Cool island intensity urban green space was investigated based in Dalsung Park, that is one of the largest parks in Daegu. Cool island intensity(CII), which is defined as the temperature difference between the green space and its surrounding built-up areas, shows time variations. A through-year measurement(2008-2009) of ground level air temperature revealed seasonal variation and relationship to the atmospheric condition of CII. The temperature variation in the park and the reference downtown Daegu was as same order as CII. The noontime CII is larger in summer than that in winter due to the leaf fall of the park trees. On the other hand, seasonal variation of nighttime CII is not so clear. The nighttime CII was larger under the stable atmosphere.
        70.
        2008.03 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to evaluate the relationship between nutrients and phytoplankton. This study was done by the comparison to two costal areas Mokpo, which inflow fresh water, and Wando. In August, salinity of the sea water decreased by 3.5-4.5‰ in Mokpo coastal area, but was not nearly decreased in Wando coastal area. This suggests a lot of fresh water inflow in Mokpo coastal area. DIN and DIP were decreased by water temperature increasing in Wando. However, in Mokpo, DIN and DIP were increased greatly during the summer season. Nitrogen was limited to a 10 N/P ratio especially during the summer season in Wando coastal area while phosphorus in Mokpo coastal area was limited with over 28 N/P ratio in all the seasons. Coefficient of determination(r2) between DIP and Chl.-a was 0.91 in Mokpo coastal area. On the other hand, Coefficient of determination(r2) between Chl.-a and DIN, DIP were 0.93 and 0.89, respectively, in Wando coastal area. These results suggest DIP in Mokpo and DIN and DIP in Wando might be limited at the increase of phytoplankton.
        71.
        2006.06 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to clarify the characteristic of urban heat island intensity in urban area formed at a basin. Thermal environments for basin-type cities are influenced by significant topographic relief winds. In this study, we analyzed the diurnal variations of the heat island intensity according to meteorological condition and season using AWS(Automatic Weather observation System) data in Daegu Metropolitan area for 1 year(3/April, 2003 ~ 2/April, 2004). In this study, we defined the urban heat island intensity as the air temperature difference between two points, the downtown and the suburban area. The suburban area is located at valley mouth around the western tip of Daegu. The results are summarized as follows; 1. The maximum heat island intensity was recorded at early morning under the meteorological conditions, calm and clear 2. The heat island intensity was strong in the order of winter, fall, spring and summer. 3. The heat island intensity came out minus values in the afternoon. This phenomenon is known as a common for basin-type cities. 4. The heat island intensity was twice or more in clear and calm than not so.
        73.
        2002.08 KCI 등재 서비스 종료(열람 제한)
        새만금간척지역은 동경 와 북위 위치하고 있다. 새만금간척지역은 대조차가 5.6m 이고 최대 조유속은 이다. 조간대 침전물의 대부분은 금강, 만경, 동진강으로부터 유입되고 있다. 이 지역의 저질은 실트질 모래로 구성되어 있다. 동절기의 바람은 북서풍이 우세하다. 새만금간척면적은 40,100ha 이고 방조제의 길이는 33km이다. 본 연구의 목적은 강 진단모델과 예보모델에 의하여 간척전 후의 잔차류의 계절변화를 규명하는 것이다.
        74.
        2001.08 KCI 등재 서비스 종료(열람 제한)
        Investigations were carried out to observe the seasonal succession of phytoplankton, and viable counts of bacteria from the mid to lower reaches of Nakdong River. An intensive monitoring was conducted from May to December 1999 biweekly at 6 sites in a main channel and 3 tributaries. Although there are several sites with high nutrient loading from the basin, all of study sites showed mesotrophic states owing to high discharge(June∼September). Relatively low algal biomass and CFUs(mean of chl. a, 12.3±11.5 ㎍/ℓ, CFUs : 1.8×10 7) were observed during the rainy season. The diatom population was dominant(over 85% of total community) year-long with peaks (Stephanodiscus hantzschii) in the fall and winter. Dominance of blue-green algal groups during the summer was not observed in the summer. Microorganisms peaked in the summer and fall (June∼September), affected mainly by the inputs of phytoplankton and nutrients. Biomass of phytoplankton and CFU counts were higher in the Kumho River than the other tributaries and main channel.
        75.
        1998.02 KCI 등재 서비스 종료(열람 제한)
        Surface heat budget of the Deukryang Bay from July 1, 1992 to September 12, 1993 is analyzed by using the meteorological data (by Changhung Observatory and Mokpo Meteorological Station) and oceanographical data (by Research Center for Ocean Industrial Development, Pukyong National University). Each flux element at the sea surface which has annual variation is derived with application of an aerodynamical bulk method and empirical formulae. The solar radiation is the maximum in spring and summer, and the minimum in autumn and winter. The effective back radiation, the latent heat and the sensible heat are the maximum in autumn and winter, and minimum in summer. The heat storage rate is calculated by using the rate of water temperature variation according to the depth. The oceanic transport heat is estimated as a residual. The net heat flux, the heat storage rate are positive in spring and summer, while they are negative in autumn and winter. The oceanic transport heat is convergence in winter and divergence in the rest of seasons.
        76.
        1997.08 KCI 등재 서비스 종료(열람 제한)
        In order to study the seasonal variation of kinetic and potential energy of residual flow field in Suyoung Bay of Korea, we calculated its energy budget and compared it with the tidal energy there. The potential energy shows the large value in winter and spring and the small one in summer and early autumn when the density stratification is developed. The kinetic energy of residual flow varies seasonally and the seasonally averaged kinetic energy of residual flow per unit area is 6.4 × 10_-4 ergs s^-1cm^-2. It is mainly governed by the density-driven current with the exception of that in November when the kinetic energy of tide-induced residual current is larger than those of density-driven current and winddriven current. An averaged fraction of the kinetic energy of tide-induced residual current, wind-driven current and density-driven current, which are the major components of residual flow, is 29.1%, 3.4%, 67.5%, respectively, to the kinetic energy of residual flow. The fraction of kinetic energy of residual flow, potential energy and tidal energy per unit area is 1.0 : 6.7 × 10_3 : 8.2 × 10_4, respectively.
        77.
        1993.02 KCI 등재 서비스 종료(열람 제한)
        우리나라 주요 벼 장려품종들의 식미관련 이화학적 특성의 품종 및 작기간변이와 이들 특성간 상관관계를 밝히고자 1991년 작물시험장 벼 품종전시포에서 보통식 및 만직재배로 생산된 23품종 및 보통식 4개 품종과 일본에서 생산된 3개 품종에 대한 아밀로스함량 및 단백질함량을 위시하여 미식미계 검정치, 취반특성, 밥의 물성, 미분의 Viscogram 특성등을 검정한 결과를 분석 검토하였던 바 그 주요결과를 요약하면 다음과 같다. 1. 보통식에 비해 만직에서 아밀로스함량, 식미계의 맛치, 취반용출액 요-드 정색도 및 취반용출액 요-드 정색도 / 용출고형물량 비등은 유의하게 증가한 반면, 식미계의 점성치, Mg/KㆍN 치, 가열흡수률, 손실정접과 setback을 제외한 viscogram 특성치 등은 현저하게 감소하는 경향이였고 대부분의 특성에서 만식의 경우 보통식에 비해 품종간변이가 좁아지는 경향이었다. 2. 작기간 변이는 거의 무시할 정도로 작으면서 주로 품종간변이에 의해 좌우되었던 특성은 단백질함량, 밥 용적팽창률, 미분의 set back 치와 Rheolograh-Micro에 의해 측정된 모든 밥의 물리적 특성치였다. 특히 작기간변이가 컸던 특성은 아미노스함량, 식미계점성치, 가열흡수률, 취반용출액 요-드 정색도/용출고형물량 비 최고 및 최저 점도, breakdown치 등이었으며 품종 작기간 교호작기용변이가 컸던 특성은 식미계의 맛치, 가열흡수률, 용출고형물량, 최종점도 및 setback치 등이었다. 3. 아밀로스함량은 조생종이 중생 내지 중만생종에 배해 낮은 편이었고 품종에 따라서 만식에 따른 함량변이정도가 달랐다. 취반용출액 요-드 정색도 / 용출고형물질 비는 일반적으로 조생종들이 작기에 따른 변화정도가 작았다. 4. 아미로스함량은 취반용출액 요-드 정색도 및 이와 용출고형물질간비와 식미계점성치는 Mg/KㆍN 치 및 맛치와 두 작기에서 모두 밀접한 상관성을 나타내었다. 또한 식미계점성치는 보통식에서 취반특성들과는 부, 손실정접과는 유의한 정상관을 나타내었으나 만식에서는 이러한 경향을 찾아 볼수 없었다. 5. 어느 작기산이든간에 취반용출액의 요-드 정색도가 높은 품종일수록 용출고형물량도 많아지는데 취반액요-드 정색도와 손실정접, 최고비도 및 breakdown치간의 필요한 상관성은 보통식에서만 유의성이 인정 되었다. 또한 취반액요-드 정색도 / 용출고형물량 비는 보통직에서 최고비도, breakdown 및 breakdown / setback치와, 만식에서 손실정접 및 동적빙성율과 고도의 부의 상관을 보였다. viscogram특성 상호간에는 두 작기에서 모두 서로 밀접한 상관성을 보였다. 6. 식미와 관련성이 높다는 이화학적 특성을 중심으로 집약분석법에 의해 공시품종들을 두 개 군으로 대별해 볼수 있었는데 한ㆍ일 양국의 양식미품종들이 서로 다른 군에 속했다.
        1 2 3 4