• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.590-596
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• 1999

The effect of evaporative cooling in alleviating seasonal variations of dairy cows raised in AlMarai Dairy Farms in the Kingdom of Saudi Arabia were studied using milking record collected during the period of 1991 to 1996. The data included 13303 and 8137 records represented winter and summer calving seasons. Evaporative cooling system improved production for cows calved in summer. The least square means of milk yield were 9631 and 9556 liter for cows calved in winter and summer seasons but no significant differences (p<0.05) were observed between the yield of two seasons. No significant effect of season on calving under evaporative cooling on most of the biweekly points of the lactation curve. The farm, parity and milk level showed a significant effect on the shape of the curve. Functions of the lactation curve like initial yield, 305 MY, peak yield, time of peak and duration were estimated for each phase of the lactation curve.

• 수산해양교육연구
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• 제29권1호
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• pp.257-269
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• 2017

The occurrence variations of decapods by season and depth off Oryuk Islets, Busan were investigated at seven stations in April and October 2009, July 2010 and January 2011. Decapods were collected by SCUBA diving at 5 m and 10 m depths. 46 species belonging to 18 families in 3 orders were identified. Pilumnus minutus, Pugettia intermedia, Pachycheles stevensii, and Paguristes japonicus were dominant species, comprising 73.0% of total decapods. P. minutus and P. intermedia were abundant in all seasons (except summer) while P. stevensii and P. japonicus were abundant in fall and summer. Dominant species were divided into three groups (resident species, seasonal species and temporary species) on the basis of their occurrence patterns. P. minutus and P. intermedia were resident species while P. stevensii, P. japonicus were temporary species. The species number, density and biomass of decapods were fluctuated by seasons. They were highest in fall and lowest in winter. This study implied that the variations of species number and density of decapods were significantly related with seasonal change of water temperature.

• 한국수산과학회지
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• 제36권5호
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• pp.474-479
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• 2003

The effect of season, life stages and harvesting sites on the yield and properties of agars extracted from Gracilaria verrucosa were determined. G. verrucosa were collected seasonally from November 2001 to August 2002 at Cheongsapo and Boryong, Korea. The plants were sorted Into the different life stages (tetrasporophytes and gametophytes) and dried at $60^{\circ}C.$ The yield, sulfate, protein, uronic acid and 3,6-anhydrogalactose of the agar were determined, and standard parameters of physical quality were measured. No differences were found in yield and properties of agars from the two different harvesting sites and from lift history phases. The yield of agar was maximum in summer $(17.3-20.0\%)$ and minimum in winter $(11.9-13.1\%).$ Maximum gel strength occurred in winter when the agar yield and sulfate content were low. Gel strength was negatively correlated with agar yleld. Seasonal variations in agar yield and its quality were discussed in a view to managing the exploitation of this resource.

• 한국수산과학회지
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• 제47권6호
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• pp.983-996
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• 2014

Fish catches by a set net from January 2007 to November 2009 were analyzed to assess fish species composition and seasonal variations in the coast of Gijang, Korea. Over 389 kg fish representing 78 species, 45 families and 17 orders were collected during three years of the study. Dominant species were jack mackerel Trachurus japonicus, anchovy Engraulis japonicus and herring Clupea palasii, and these three species comprised 67.3% of the total number of individuals and 60.7% of the total biomass. Size distribution of the dominant species for jack mackerel, anchovy and herring ranged from 2.2 cm to 22.6 cm, from 2.5 cm to 14.8 cm, from 4.0 cm to 29.0 cm in fork length, respectively. Anchovy was the only species that occurred throughout all seasons in the Gijang coast. Generally, species richness was highest in spring (April to June) when sea temperature began to increase.

• 한국식품영양과학회지
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• 제24권2호
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• pp.268-273
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• 1995

To study the nutritional value of warty sea squirt, Styela clava, which is one kind of urochoda and it has been used as special seafood stuffs by Korean, the seasonal variations of nutrient was investigated. The moisture content was ranged from 83.6% to 86.8% in experimental period. Maximun glycogen content showed up in June (3.7g/100g sample). The protein(N$\times$6.25) and lipid content varied with glycogen whereas ash content was not changed remarkably, showing 2.8$\pm$0.3%. Predominant minerals in edible portion and integuments were sodium, potassium, calcium and magnesium in order. Predominant constitutiional amino acids were asparagine, glutamic acid, taurine, aspartic acid, lysine and glycine and amino acids occupied 50% of the total amino acid. Porportion of nonpolar lipid to total lipid increased from April to early June while polar lipid level decreased. The neutral lipid was composed of triglyceride(59.32%) and free sterol(23.52%), and followed by diglycerides, monoglycerides, esterified sterols and hydrocarbon, free fatty acid. The phospholipid was mainly composed with phosphatidyl choline(49.7%), and phosphatidyl ethanolamine(33.0%). The major fatty acids of the total lipid in warty sea squirt were C20 : 5(17%), C22 : 6(13.76%), C16 : o(13.91%) and C16 : 1(12.52%).

• 한국환경보건학회지
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• 제26권2호
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• pp.108-115
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• 2000

The mass fraction of PM10 had a bimodal distribution in the middle of between 2.1 ${\mu}{\textrm}{m}$, and the average mass fraction of particles less than 2.1~3.1 ${\mu}{\textrm}{m}$ was 54.1% for Pb and 890.8 ng/㎥ for Fe, respectively. For the concentration of PM10 and metallic elements by seasonal variation, PM10 showed bimodal distribution, while metallic elements showed different distributions by their sources. The ratios of fine particles to total mass were 0.45 for PM10, 0.41 for Cr, and 0.20 for Fe, 0.57 for Zn, 0.68 for Cd and 0.63 for Pb, respectively. That facts indicated that PM10, Zn, Cd, Cr and Pb were from anthropogenic sources, and Fe was from natural source. The geometric means and geometric standard deviations by seasonal variations were 3.6 ${\mu}{\textrm}{m}$ , 2.31 ${\mu}{\textrm}{m}$ in winter, 3.0 ${\mu}{\textrm}{m}$ , 2.49 ${\mu}{\textrm}{m}$ in spring, 2.7 ${\mu}{\textrm}{m}$ , 2.03 ${\mu}{\textrm}{m}$ in summer respectively. And, total efficiency of cascade impactor by seasonal variations were 49.6% in winter, 45.9% in spring and 44.5% in summer.

• 한국지구과학회지
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• 제35권7호
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• pp.537-542
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• 2014

GRACE는 2002년 발사된 이래로 지하수, 빙하, 해수면의 변동에 의한 지구의 질량 재배치를 관측해오고 있다. GRACE 관측으로부터 추정된 지구 중력 모델은 기압보정을 거쳐 대기 질량이 제거된 지구 표면과 그 하부의 질량 변화를 나타낸다. 그러나 대기 총 질량은 지표면과 대기 사이의 물 교환에 의해 변한다. 그 결과 GRACE 중력 모델은 구면 조화 함수의 계수 degree 0, order 0 ($C_{00}$)에 해당하는 총 대기 질량 변화에 관련된 중력 스펙트럼을 가져야 한다. 주로 계절적인 시간 척도 안에서 변하는 수증기 때문에 $C_{00}$의 변화(${\delta}C_{00}$)는 특히 해수면의 계절적 변동과 북반구와 남반구 사이의 질량 균형에 매우 중요하다. 이 결과는 ${\delta}C_{00}$가 기후변동과 관련된 대륙 규모의 질량 변화 연구에 꼭 고려되어야 함을 뜻한다.

• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.329-336
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• 2012

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth's geomagnetic filed by space weather, we use the international quiet days' data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components' quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation's amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth's atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.

• 한국해양학회지:바다
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• 제13권3호
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• pp.200-209
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• 2008

2003년 7월부터 2005년 6월까지 약 24 개월 동안 북동태평양 대한민국 망간단괴 개발광구 내에 위치한 정점 KOMO(Korea Deep-Sea Environmental Study Long-Term Monitoring Station, $10^{\circ}30'N,\;131^{\circ}20'W$)에서 시계열 퇴적물 포집장치를 설치하여 물질 플럭스를 측정하였다. 약 4,960 m 수심에서 획득된 침강입자의 총질량 플럭스는 겨울(12월-2월)과 봄(3월-5월)에 높고, 여름(6월-8월)과 가을(9월-11월)에 낮은 뚜렷한 계절변동을 보였다. 생물기원 물질플럭스도 총질량 플럭스와 유사하게 뚜렷한 계절변동을 나타냈다. 특히, 겨울과 봄에 관측된 탄산염 플럭스는 여름과 가을보다 두 배가량 높게 측정되어, 다른 생물기원 구성성분들의 계절변동에 비해 가장 크게 나타났다. 심해저층에서 관측된 침강입자의 총질량 플럭스와 생물기원 물질플럭스는 표층 해양 일차 생산력의 계절변동을 반영하는 것으로 생각된다. 겨울과 봄에는 강한 바람의 영향으로 혼합층 아래로부터 영양염의 공급이 증가되어 일차생산력이 높아진 것으로 생각되며, 여름과 가을에는 바람의 약화와 강한 성층으로 인하여 영양염 공급이 약해져서 일차생산력이 감소한 것으로 판단된다. 침강입자의 총질량 플럭스와 생물기원 물질플럭스의 계절적 변동은 이전에 연구된 엘니뇨/라니냐와 같은 환경변화에 따른 물질플럭스의 변화보다 크게 나타났다. 따라서 북동태평양 적도지역에서 엘니뇨와 라니냐 같은 환경변화의 영향에 의한 해양 물질플럭스의 변화를 이해하기 위해서는 일반적인 계절적 변동을 정확하게 측정하여야 한다.

• 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.