• Title/Summary/Keyword: Seasonal Variations

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Response of Soil CO2 Fluxes to Seasonal Variations in a Grassplot (잔디밭에서 계절 변화에 따른 이산화탄소 플럭스 변동)

  • Kim, Park Sa;Kwon, Byung Hyuk;Kang, Dong Hwan
    • Journal of Environmental Science International
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    • v.23 no.6
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    • pp.1131-1142
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    • 2014
  • In this study, the variations of the carbon dioxide fluxes were investigated with soil temperatures in the grassplot and seasonal variations of carbon dioxide concentrations and fluxes were analysed. Soil temperatures, carbon dioxide concentrations and fluxes were measured on the grassplot in Pukyong National University. Field measurements were carried out 25 times from March in 2010 to March in 2011 with nine points on the grassplot. Seasonal variations of carbon dioxide concentrations and fluxes showed an inverse relation. In summer, carbon dioxide concentrations are lower and carbon dioxide fluxes are higher. In winter, carbon dioxide concentrations are higher and carbon dioxide fluxes are lower. On the grassplot, carbon dioxide emission rate increase when the soil temperature is more than $20^{\circ}C$ and the emission rate decrease when the soil temperatures are less than $10^{\circ}C$. When the accumulated rainfall for five days before measurement day is 20~100 mm, it is showed that the more rainfall, the more carbon dioxide emissions. Carbon dioxide emission rate from the grassplot to the upper atmosphere was increased or decreased by the factors such as soil temperature, growth and wither of grass and rainfall. The results of this study showed that the emission of carbon dioxide in the grassplot is dominantly controlled by seasonal factors (especially soil temperature and rainfall).

Seasonal Variations of Digestive Diverticula in the Scallop, Patinopecten yessoensis (가리비, Patinopecten yessoensis 소화맹낭의 계절변화)

  • Chang, Young-Jin
    • Journal of Aquaculture
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    • v.4 no.1
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    • pp.19-30
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    • 1991
  • The seasonal variations of digestive diverticula in the scallop, Patinopecten yessoensis culturing by sowing method were studied by microscopic observations and individual measuring of the shells collected monthly from Abashiri Bay located in Hokkaido, Japan. Digestive diverticula index revealed the seasonal variations which showed the highest value in May and July, and the lowest value in December through April. The highest number of tubules per $mm^{2}$in the preparation of digestive diverticula was counted in March. But, in September and October the number of tubules decreased to the lowest value. The relationship between gonad index(X) and percent of lipid tubule(Y) as an indicator for the transference of lipid in digestive diverticula into the gonad was expressed by an exponential equation, $Y=145.6X^{-0793}$. It was suggested that the lipid in digestive diverticula showed the seasonal variations might be transferred into the gonad.

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Seasonal Variations of Exposure to Environmental Chemicals: Implication from the Korean National Environmental Health Survey (2012-2014) (환경오염물질 노출수준의 계절적 변이와 그 함의 - 제2기 국민환경보건기초조사(2012-2014))

  • Hwang, Moon-Young;Ryu, Jung-Min;Kown, Young-Min;Hong, Soo-Yeon;Park, Choong-Hee
    • Journal of Environmental Health Sciences
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    • v.44 no.6
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    • pp.572-580
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    • 2018
  • Objectives: Human biomonitoring (HBM) is a measurement of the chemicals and their metabolites in human biological samples and has been successfully employed to determine the exposure levels of environmental chemicals. In this study, we analyzed seasonal variations of the blood or urinary levels of chemicals, and assessed that these differences could affect the results of association study. Methods: The Korea National Environmental Health Survey (KoNEHS) is a nationwide survey that analyzes exposure levels of environmental pollutants, 19 kinds of chemicals including heavy metals and organic chemicals, and the exposure factors in the general population. Based on KoNEHS data, we analyzed the levels of chemicals concentrations over the total survey period (2012-2014) and each season, and assessed the association of thyroid measures with phthalate metabolite and BPA. Results: Exposure levels of blood mercury and lead were lower in summer compare to winter. Bisphenol A and PAHs metabolites were higher in spring and summer, but lower in autumn. VOCs metabolites were generally lower in summer and autumn. Phthalate metabolites were higher in all other seasons than in winter. Pyrethroid metabolite, 3-PBA, was higher in summer and autumn. Regarding seasonal variation of chemical exposures, the statistical significance and size of effects between thyroid measures and phthalate and BPA were changed with season. Conclusion: Seasonal variations of chemical exposure and health outcome should be considered for interpreting biomonitoring results from a public health context.

Relationship between Sea Surface Temperature and Air Temperature Variation Depend on Time Scale at Coastal Stations in Korea (시간스케일에 따른 해양표면수온과 기온의 변동 및 상관연구)

  • 장이현;강용균;서영상
    • Journal of Environmental Science International
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    • v.9 no.4
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    • pp.303-309
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    • 2000
  • The relationship between air temperature and sea surface temperature and studied using the daily air temperature and sea surface temperature data for 25 years (1970~1994) at 9 coastal stations in Korea. Seasonal variations of air temperature have larger amplitudes than those of sea surface temperature. The seasonal variations of air temperature leads those of sea surface temperature by 2 to 3 weeks. The anomalies of sea surface temperature and air temperature with time scales more than 1 month are more ghighly correlated than those of short term, with time scales less than 1 month. Accumulated monthly anomalies of sea surface temperature and air temperature for 6 months shwoed higher correlation than the anomailes of each month. The magnitudes of sea surface temperature and air temperature anomalies are related with the duration of anomalies. Their magnitudes are large when the durations of anomalies are long.

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Seasonal Variations of Monoterpene Concentrations in a Pine Forest in Florida, USA

  • Kim, Ki-Hyun;Kim, Jo-Chunn
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.E3
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    • pp.175-180
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    • 2002
  • In order to study the distribution characteristics of natural volatile organic compounds (NVOCs), we investigated the seasonal variations of $\alpha$-and $\beta$-pinene levels in a pine forest in Florida for a you. The mean concentrations of $\alpha$- and $\beta$-pinene measured during the whole study period were computed to be 125: 86 (N = 65) and 86$\pm$52 pptv (N = 56), respectively. According to our data grouping scheme, the seasonal means for both pinones were observed to peak during fall with their max and min values in summer and winter, respectively. The overall results of our study suggest that terpenes are subject to highly strong temporal variability because of changes in their major source characteristics across seasons.

Seasonal Variations of Phytoplankton Community and Water Quality in the East Area of Chinhae Bay (진해만 동부 해역내 식물플랑크톤 군집과 수질환경의 계절 변동)

  • 여환구;박미옥
    • Journal of Environmental Science International
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    • v.6 no.3
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    • pp.231-238
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    • 1997
  • The community of phyloplankton and water quality were Investigated 5 times from October, 1994 to October, 1995 In the east area of Chinhae Bay. Seasonal changes of enoronmental parameters were shown general pattern and related to the red tide mechanism of phytoplankton community. Seasonal variations of dissolved oxygen concentrations were affected by the photosynthetic activity of phytoplankton community and the Increase of COD at the bottom water was occurred after the red tide. The standing stocks of phytoplankton In this study area ranged 202 - 1616 Cells . ml-1 and the bloom(red tide) was formed from April to July. The diatom species, Skeletonema costahm was a dominant species all the year round and the dinoflagellate species, Alexandrium tmuense and prorocentrum triestinum were red tide species Increased standing stocks in phytoplankton bloom.

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Study on Response of Ecosystem to the East Asian Monsoon in Eastern China Using LAI Data Derived from Remote Sensing Information

  • Zhang, Jiahua;Yao, Fengmei;Fu, Congbin
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1298-1300
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    • 2003
  • Based on the Leaf Area Index (LAI) data derived from remote sensing information and eco-climate data, the responses of regional ecosystem variations in seasonal and interannual scales to the East Asian monsoon are studied in this paper. It is found that the vegetation ecosystems of eastern China are remarkably correlated with the East Asian monsoon in seasonal and interannual scales. In the seasonal timescale, the obvious variations of the vegetation ecosystems occur with the development of the East Asian monsoon from the south in the spring to the north in the autumn. In the interannual scale, high LAI appears in the strong East Asian monsoon year, whereas low LAI is related to the weak East Asian monsoon year. These further lead to the characteristic of 'onsoon-driven ecosystem' in the eastern China monsoon region, which can be revealed by LAI.

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A Longitudinal Study on Seasonal Variations of Physical Activity and Body Composition of Rural Women (농촌여성들의 계절별 활동량과 체성분 차이에 관한 종단 연구)

  • 임화재
    • Journal of Nutrition and Health
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    • v.28 no.9
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    • pp.893-903
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    • 1995
  • This study was attempted to estimate seasonal variations of physical activity level, energy balance & body composition of 38 rural women, aged 31 to 67yrs in three seasons ; farming season(June), harvesting season(October), nonfarming season(February) Energy intake, energy expenditure and body composition were assessed using questionnaire, daily activity diary & bioelectrical impedance. The type of activities & the period of the spent on each activity were changed significantly with the seasons. Daily mean duration(min) of farming activity was significantly higher in June & October than in February(p<0.005) & daily mean energy expenditure for farming activity was significantly high in June & low inFebruary (p<0.005). Daily mean energy expenditure was 2892.9㎉ in June, 2487.4㎉ in October and 2130.9㎉ in February and changed significantly in three seasons(p<0.005). Daily mean energy intake was significantly higher in June(=1950.3㎉) & October (=1946.9㎉) than in February(=1423.3㎉)(p<0.005). According to RDA for koreans, the level of physical activity fell into exceptional activity category in June, heavy in October, moderate in February. Mean energy balance was negative in all seasons ; 0.682 in June, 0.812 in October and 0.698 in February. In three seasons mean body weight, mean obesity rate and mean body mass index(BMI) were not changed significantly. But there were significant seasonal variations in body fat(%) & lean body mass(LBM)(%). The mean percentage of body fat(%) was within normal range(24.44-24.79%) & the mean percentage of lean body mass(LBM)(%) representing long term physical activity was significantly higher in June(75.56%) & October(75.21%) & October (75.21%) than in February(72.75%)(p<0.05).

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Variations of the PM10 Concentrations Observed in Eleven Cities in South Korea between 1995 and 2000 (한반도 11개 도시의 1995~2000년 PM10 농도 변화 경향)

  • 진윤하;구해정;김봉만;김용표;박순웅
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.2
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    • pp.231-245
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    • 2003
  • Hourly PM$_{10}$ concentrations measured at 11 sites in Seoul and 10 sites in the large cities over South Korea for the period from March 1995 to February 2000 are analyzed to examine annual trend and monthly variations of the PM$_{10}$ concentrations. Further analysis has been carried out by using the one year data from March 1999 to February 2000 to see the seasonal variation, diurnal variation and weekly variation of the seasonally averaged PM$_{10}$ concentrations at each site. Weekly variations of the CO concentrations at the same sites for the same one year period are compared with that of the PM$_{10}$ concentration. There is no significant annual trend in the variation of the PM$_{10}$ concentration at all the sites analyzed. The seasonal and monthly mean concentrations show a minimum concentration in summer and alternative maximum concentration in spring and winter for most sites. The diurnal variation of the seasonally averaged mean PM$_{10}$ concentrations is strongly affected by traffic loads and meteorological conditions. The weekly variation of seasonal averaged concentrations of CO and PM$_{10}$ shows a high concentration for weekdays in spring, autumn and winter while high concentration for weekends in summer.nds in summer.

Seasonal and solar activity variations of the Weddell Sea Anomaly observed in the TOPEX TEC measurements

  • Jee, Geon-Hwa;Burns, Alan G.;Kim, Yong-Ha;Wang, Wen-Bin
    • Bulletin of the Korean Space Science Society
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    • 2008.10a
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    • pp.25.1-25.1
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    • 2008
  • The Weddell Sea Anomaly (WSA) in the ionosphere is characterized by higher plasma density at night than during the day in the region near the Weddell Sea. According to previous studies on the WSA, it is known to occur mostly in southern summer and has not been reported in other seasons. We have utilized more than 13-year TOPEX TEC measurements in order to study how the WSA varies with seasons and how it changes with solar activity. The TOPEX TEC data have been extensively utilized for the climatological study of the ionosphere due to its excellent spatial and temporal coverage. We investigate the seasonal and solar activity variations of the WSA using four seasonal cases (Mar. equinox, Jun. solstice, Sep, equinox, and Dec. solstice) and two solar activity conditions (F10.7<120 for solar minimum and F10.7>120 for solar maximum conditions) for geomagnetically quiet periods. Our analysis shows that the WSA occurs only in the southern summer hemisphere for low F10.7, as in previous studies, but the WSA occurs all of seasons except for winter when F10.7 is high: it is most prominent during the December solstice (southern summer) and still strong during both equinoxes. The WSA appears to be an extreme case of global longitudinal variations at mid- and high-latitudes.

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