• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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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.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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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%).

• Journal of Environmental Health Sciences
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• v.26 no.2
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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.

• Journal of the Korean earth science society
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• v.35 no.7
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• pp.537-542
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• 2014

The Gravity Recovery and Climate Experiment (GRACE) has observed the Earth's mass redistribution mainly caused by the variations of groundwater, ice sheet, and sea level since its launch in April 2002. The global gravity model estimated by the GRACE observation is corrected by barometric pressure, and thus represents the change of Earth mass on the Earth's surface and below Earth's surface excluding air mass. However, the total air mass varies due to the water exchange between the Earth's surface and the atmosphere. As a result, the nominal GRACE gravity model should include the Earth's gravity spectrum associated with the total air mass variations, degree 0 and order 0 coefficients of spherical harmonics ($C_{00}$). Because the water vapor content varies mainly on a seasonal time scale, a change of $C_{00}$ (${\delta}C_{00}$) is particularly important to seasonal variations of sea level, and mass balance between northern and southern hemisphere. This result implies that ${\delta}C_{00}$ coefficients should be accounted for the examination of continental scale mass change possibly associated with the climate variations.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.200-209
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• 2008

Particle fluxes were measured with a time-series sediment trap from July 2003 to June 2005 at the St. KOMO(KOMO; Korea Deep-Sea Environmental Study Long-Term Monitoring Station, $10^{\circ}30'N,\;131^{\circ}20'W$) in the northeastern Pacific. Total mass fluxes at a depth of 4,960 m showed distinct seasonal variations with high values in the winter(December-February) and spring(March-May) and low values in the summer(June-August) and fall(September-November). Biogenic origin fluxes also displayed distinct seasonal variations similar to total mass fluxes. Particularly, calcium carbonate fluxes in winter and spring were more than two times greater than those in summer and fall. The prominent seasonal variations of total mass and biogenic fluxes were closely related with the seasonal changes of primary production in the surface waters; in winter and spring, primary production increased due to the enhanced supply of nutrients below the surface mixed layer by strong wind and less stratification, whereas it decreased as a result of the less supply of nutrient by reduced wind speed and strong stratification in summer and fall. The seasonal variations of total mass and biogenic fluxes in this study were higher than the differences of total mass and biogenic fluxes caused by the environmental changes such as El $Ni\tilde{n}o$ and La $Ni\tilde{n}a$ events in the previous studies. In order to understand the effects of El $Ni\tilde{n}o$ and La $Ni\tilde{n}a$ on the particle flux, therefore, the seasonal variation of particle flux in the northeastern equatorial Pacific needs to be well defined.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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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.