• 한국환경과학회지
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• 제21권1호
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• pp.23-30
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• 2012

The aerosol number concentration have measured with an aerodynamic particle sizer spectrometer(APS) at Gosan site in Jeju, Korea, from March 2010 to March 2011. And then the atmospheric aerosol number concentration, the temporal variation and the size distribution of aerosol number concentration have been investigated. The aerosol number concentration varies significantly from 748 particles/$cm^3$ to zero particles/$cm^3$. The average number concentration in small size ranges are very higher than those in large size ranges. The number concentrations in the size range 0.25~0.28 ${\mu}m$, 0.40~0.45 ${\mu}m$ and 2.0~2.5 ${\mu}m$ are about 84 particles/$cm^3$, 2 particles/$cm^3$ and 0.4 particles/$cm^3$, respectively. The number concentrations in range of larger than 7.5 ${\mu}m$ are below 0.001 particles/$cm^3$. The seasonal variations in the number concentration for smaller particle(<1.0 ${\mu}m$) are not much, but the variations for larger particle are very evident. And strong amplitudes of diurnal variations of entire averaged aerosol number concentration are not observed. Size-fractioned aerosol number concentrations are dramatically decreased with increased particle size. The size-fractioned aerosol number concentrations in size range 0.8~4.0 ${\mu}m$ during nighttime are evidently higher than during daytime, but similar levels are appeared in other size range. The seasonal differences in the size-fractioned number concentrations for smaller size range(<0.7 ${\mu}m$) are not observed, however, the remarkable seasonal differences are observed for larger size than 0.7 ${\mu}m$.

• 한국수산과학회지
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• 제25권2호
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• pp.151-163
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• 1992

황해, 동지나해와 제주도 주변해역의 해수분포의 계절변화를 살펴본 결과 이 해역전반에 걸쳐 공통된 계절변화가 보였다. 고온고염의 해수는 겨울에 황해 쪽으로 확장되며 여름에 동지나해 쪽으로 후퇴한다. 순압모델결과는 계절풍이 이와 같은 해수분포의 계절변화를 유도할 수 있음을 보여준다. 역풍류는 이 과정에서 중요한 역할을 하는데, 모델결과에는 역풍류의 축이 중국 쪽으로 이동되어 나타난다. 역풍류 축의 이동은 황해북부의 복잡한 해안선과 얕은 해저지형에 의한 에너지손실에 기인한다. 수치모델결과에 나타난 이동된 역풍류의 길은 여름철 황해저층냉수 남하의 길과 잘 일치한다.

• Ocean and Polar Research
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• 제31권2호
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• pp.219-229
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• 2009

In order to establish annual variations in the marine ecosystem of the East China Sea, suspended solids (SSs) and particulate organic carbon (POC) were extensively investigated in the northern part of the East China Sea from August 2003 to April 2008. Surface SS concentrations showed large spatial variations in spring and fall, but not in summer. Surface SS concentrations in spring were lower than those in summer and fall. In summer, SSs discharged from Changjiang were mostly deposited in the coastal areas and did not reach our study area which was located about 260 km from the river mouth. High SS concentrations were observed near the bottom, which resulted from resuspension of bottom sediments by the bottom currents. Surface POC concentrations did not exhibited large seasonal variations. Phytoplankton biomass was a main factor controlling surface POC concentrations. POC/chlorophyll ratios showed large seasonal variations, with maximum numbers in summer. POC/PON ratios were higher in summer than the Redefied ratio (6.6), while they were lower in spring and fall. In summer, higher POC/chlorophyll and POC/PON ratios were probably attributed to the high phytoplankton mortality caused by nutrient depletion in surface waters.

• 대한화학회지
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• 제6권2호
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• pp.176-197
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• 1962

Seasonal variations of chemical constituents of estuarine water at a definite station of the tidal flat in Guang Yang inlet have been determined for two days a month. The range and mean of the annual variations are as follows:Tidal variations through a year are as follows:1. Although the tidal value of pH is almost constant during one tidal cycle, it raises abruptly 0.1-0.2 intervals of pH value during the first period of flood.2. The lower values of chlorinity, magnesium and calcium contents have been determined the nearer the slack after ebb, and slightly higher during the first period of flood tide than the last of ebb. The tidal change of calcium contents is more remarkable than of magnesium.3. The higher per cent saturation values of dissolved oxygen, sometimes higher than 100 per cent, re determined the nearer the slack after ebb.4. The total nitrogen contents, relatively poor, varies accidentally during one tidal cycle, whereas phosphate-P and silicate-Si are rich at the slack after ebb and increase proportionally to the mixing percentage of fresh water. The average values, 52.2 and 18.5 of Si/P and N/P are greater than of the normal.5. The acid soluble iron contents, lower in winter than in summer, is also varies accidentally during one tidal cycle and the magnitude of the variation is large.6. The chemical composition considered from the value of Ca/Cl or Mg/Cl of estuarine water varies according to the chlorinity even at the high chlorinity of 18-19%.

• 대기
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• 제18권4호
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• pp.475-483
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• 2008

The hourly precipitation data from 1973 to 2007 observed at 60 weather stations over Korea are used to characterize the diurnal and semidiurnal cycles of total precipitation amount, intensity and frequency and examine their spatial patterns and interannual variations. The results show that the diurnal cycle peaks in the morning (03-09LST) and the semidiurnal cycle peaks in the late afternoon (16-20LST). It is found that the spatial variations of the peak phase of diurnal or semidiurnal cycle relative to their corresponding seasonal mean cycle are considerably small (large) for total precipitation amount and intensity (frequency, respectively) in both winter and summer seasons. Also, the diurnal phase variations for individual years relative to the seasonal mean precipitation show the significant interannual variability with dominant periods of 2-5 years for all three elements of precipitation and the slightly decreasing trend in total precipitation amount and intensity. To compare the relative contributions of frequency and intensity to the diurnal and semidiurnal cycles (and their sum) of total precipitation amount, the percentage variance of each cycle of precipitation amount explained by frequency is estimated. The fractional variance accounted for by precipitation intensity is greater than that of frequency for these three cycles. All above analyses suggest that intensity plays a more important role than frequency in the diurnal variations of total precipitation amount.

• 한국환경과학회지
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• 제29권11호
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• pp.1141-1151
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• 2020

The impact of sound speed variability in the sea is the very important on acoustic propagation for the underwater acoustic systems. Understanding of the temporal and spatial variability of ocean sound speed in the sea around the Ieodo were obtained using oceanographic data (temperature, salinity). from the Korea Oceanographic Data Center, collected by season for 17 years. The vertical distributions of sound speed are mainly related to seasonal variations and various current such as Chinese coastal water, Yellow Sea Cold Water (YSCW), Kuroshio source water. The standard deviations show that great variations of sound speed exist in the upper layer and observation station between 16 and 18. In order to quantitatively explain the reason for sound speed variations, Empirical Orthogonal Function (EOF) analysis was performed on sound speed data at the Line 316 covering 68 cruises between 2002 and 2018. Three main modes of EOFs respectively revealed 55, 29, and 5% the total variance of sound speed. The first mode of the EOFs was associated with influence of surface heating. The second EOFs pattern shows that contributions of YSCW and surface heating. The first and second modes had seasonal and inter-annul variations.

• 한국해양학회지
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• 제27권4호
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• pp.290-302
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• 1992

기후학적인 관측자료와 담수 효과를 고려한 수치실험에서 얻어진 두가지의 계절별 염분 분포를 열대 대서양 500 m 상층부에 대하여 조사하였다. 해표면 염분의 계절 변 화는 담수의 초과를 가져오는 열대수렴대(ITCZ)의 이동 및 강물 방출 시기에 밀접한 관계가 있었다. 본 연구에서 얻어진 계절별 염분 분포는 Defant (1981)와 Levitus (1982) 등의 이미 존재하는 기후 자료와 대체로 비슷하나, 본 연구의 자료가 온도 분 포에 더 잘 일치하였다. 밀도에 대한 온도 효과와 비교할 때 염분 효과는 100 m 이심 에서는 무시할 만하나 혼합층에서 염분 효과는 상당히 중요하였다. 관측된 염분 분포 와 모델에서 계산된 염분 분포사이에 뚜렷한 차이가 염분값의 위도에 따른 기울기에서 나타났다. 모델에서 유도된 염분은 관측값보다 적도부근의 해양에서 대체로 높게 나타 났으나, 아열대 해역에서는 낮게 나타났다. 남동 대서양 해역과 같은 관측자료가 매우 적은 곳에서 염분 차이는 크게 나타났고, 이런 해역에서 정교한 모델값이 좀 더 정확 한 듯 보인다. 또한 관측값과 모델에서 얻어진 값과의 불일치에 대한 가능한 원인들도 분석하였다.

• 한국도로학회:학술대회논문집
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• 한국도로학회 2004년도 학술발표회 논문집
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• pp.27-34
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• 2004

• 복식문화연구
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• 제8권3호
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• pp.374-386
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• 2000

This study investigated the relation between seasonal variation of total clothing weight, room, outdoor temperature and basal metabolic rate in man. The basal metabolic rate and total clothing weight, room temperature was determined seasonal for a period of two years and grouped four seasons. Subjects (adults volunteers) who live in seoul and mokpo were compose 120 subject The results were obtained as follows. Seasonal outdoor temperature was difference of seoul and. mokpo. But room temperature in apartments was a little difference than private house. Total-clothing weight is showed seasonal variations at the seoul, private house than at the mokpo, apartment.. The basal metabolic rate is suggested there in gender difference in the basal metabolic rate (P〈.001). The basal metabolic rate increased gradually with the peak of winter sespectively and deceased again todward summer. The difference of between basal metabolic rate in summer and winter was significant room temperature, of seoul and private house, and light total clothing weight.

• 한국해안해양공학회지
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• 제11권2호
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• pp.116-126
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• 1999

본 논문에서는 해양 수중 다공확산관을 통해 하수종말처리장에서 1차 처리된 하·폐수를 해양방류하고 있는 마산만에서 방류수의 근역 희석률에 대한 계절별 변화를 고찰하였다. 방류수역에서 관측된 수온·염분의 수직분포와 대조기·소조기의 유속 자료를 입력하여 CORMIX 모형으로 계절별 희석률을 구하였다. 수심 15m 내외의 방류수역에서 수직적 등밀도 혼합이 전 층에서 형성되는 겨울철과 가을철 순으로 방류수의 근역 희석률이 가장 높았으며, 수온약측이 점차 깊어지는 여름철에는 희석률이 크게 감소하였다. 주변해수의 유동성에 따른 난류확산이 작은 소조기 정체시에는 여름철의 희석률이 겨울철보다 약 1/4정도로 작으며, 유속이 큰 대조기에는 두 계절의 차이가 30%정도로 적었다. 이는 여름철의 조류가 약한 정체시에 방류하수로 인한 수질오염이 마산만 방류수역에 가장 심하게 나타날 것으로 사료된다.