• Title/Summary/Keyword: 계절 변화

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Seasonal characteristics of zooplankton community in the Mid-eastern part of the Yellow Sea (황해 중동부 해역 동물플랑크톤의 계절적 분포 특성)

  • 황학진;최중기
    • 한국해양학회지
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    • v.28 no.1
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    • pp.24-34
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    • 1993
  • In order to study the seasonal characteristics of species composition and abundance, zooplankton samples were collected from April 1987 to June 1988 with bimonthly intervals in the Mid-Eastern part of the Yellow sea. Among the 24 species of 18 genera occurred in this study area, 17 species are copepods. Noctiluca scintillant has greatly influenced on the distribution of the zooplankton in the coastal area and some copepods may be excluded by its great occurrence. the seasonal variation of abundance of copepods accounting for 30-63.4% of total zooplankton were more varied among stations in the coastal area than in the offshore. It suggests that environmental factors are more variable in the coastal area than in the offshore. In the Copepod community, Acartia omorii, Paracalanus parvus and Corycaeus affinis were predominant in April and June, from August to December and in December, respectively. Sagita enflata as a Kuroshio indicator species, occurred in the study area from August to December. The great occurrence of warm water species, Doliolum sp. in October and the occurrence of Sagitta enflata from August to December suggested that there is a influx of the tributaries of Kuroshio current into the study area. It appeared that the seasonal characteristics of species composition and abundance of zooplankton were affected by the seasonal variation of water mass.

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Differences in Phenological Phases of Plants Subsequent to Microclimate Change (미기후 변화에 따른 식물계절 차이)

  • Jo, Hyun-Kil;Ahn, Tae-Won
    • Korean Journal of Environment and Ecology
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    • v.22 no.3
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    • pp.221-229
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    • 2008
  • This study observed and compared phenological changes in the spring for some native woody plants growing at Mt. Jumbong and Mt. Bongeui located at central districts of our country, and also inquired into the phenological difference subsequent to microclimate change by measuring its related environment factors as well. The average air temperature at a survey point of Mt. Jumbong from January to May in 2004 was $4.1^{\circ}C$ lower than that of Mt. Bongeui. As for the soil temperature in April by a survey section within Mt. Jumbong, the soil temperature on the west and northwest slopes was $1.8^{\circ}C$ and $4.4^{\circ}C$ lower than that of the south slope, respectively. It was found that the earliest tree species in a flowering period was Lindera obtusiloba among the sample woody plants and its flowering began in late March at Mt. Bongeui and in early April at Mt. Jumbong. The flowering of the same species began faster on the south slope than the west or north slope; in case of the tree species flowering in early spring, there appeared about two-week interval between the survey sites. Likewise, leafing time of the same species was two weeks earlier at Mt. Bongeui(in mid-April) than at Mt. Jumbong(in early May). Nuttonson's Index and Year Day Index for the flowering and leafing time of the same species showed similar value between the survey sites. It is analyzed that the transition in phenological phases between the sites is mainly caused by temperatures; further, it is implied that the climate changes and rise in temperatures could expedite the changes in phenological phases more than ever.

Spatio-Temporal Changes in Seasonal Multi-day Cumulative Extreme Precipitation Events in the Republic of Korea (우리나라 사계절 다중일 누적 극한강수현상의 시·공간적 변화)

  • Choi, Gwangyong
    • Journal of the Korean association of regional geographers
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    • v.21 no.1
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    • pp.98-113
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    • 2015
  • In this study, spatial and temporal patterns and changes in seasonal multi-day cumulative extreme precipitation events defined by maximum 1~5 days cumulative extreme precipitation observed at 61 weather stations in the Republic of Korea for the recent 40 years(1973~2012) are examined. It is demonstrated that the magnitude of multi-day cumulative extreme precipitation events is greatest in summer, while their sensitivity relative to the variations of seasonal total precipitation is greatest in fall. According to analyses of linear trends in the time series data, the most noticeable increases in the magnitude of multi-day cumulative extreme precipitation events are observable in summer with coherences amongst 1~5 days cumulative extreme precipitation events. In particular, the regions with significant increases include Gyeonggi province, western Gangwon province and Chungcheong province, and as the period for the accumulation of extreme precipitation increases from 1 day to 5 days, the regions with significantly-increasing trends are extended to the Sobaek mountain ridge. It is notable that at several scattered stations, the increases of 1~2 days cumulative extreme precipitation events are observed even in winter. It is also observed that most distinct increasing tendency of the ratio of these multi-day cumulative extreme precipitation to seasonal total precipitation appears in winter. These results indicate that proactive actions are needed for spatial and temporal changes in not only summer but also other seasonal multi-day cumulative extreme precipitation events in Korea.

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A Phenology Modelling Using MODIS Time Series Data in South Korea (MODIS 시계열 자료(2001~2011) 및 Timesat 알고리즘에 기초한 남한 지역 식물계절 분석)

  • Kim, Nam-Shin;Cho, Yong-Chan;Oh, Seung-Hwan;Kwon, Hye-Jin;Kim, Gyung-Soon
    • Korean Journal of Ecology and Environment
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    • v.47 no.3
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    • pp.186-193
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    • 2014
  • This study aimed to analyze spatio-temporal trends of phenological characteristics in South Korea by using MODIS EVI. For the phenology analysis, we had applied double logistic function to MODIS time-series data. Our results showed that starting date of phenology seems to have a tendency along with latitudinal trends. Starting date of phenology of Jeju Island and Mt. Sobeak went back for 0.38, 0.174 days per year, respectively whereas, Mt. Jiri and Mt. Seolak went forward for 0.32 days, 0.239 days and 0.119 days, respectively. Our results exhibited the fluctuation of plant phonological season rather than the change of phonological timing and season. Starting date of plant phenology by spatial distribution revealed tendency that starting date of mountain area was late, and basin and south foot of mountain was fast. In urban ares such as Seoul metropolitan, Masan, Changwon, Milyang, Daegu and Jeju, the phonological starting date went forward quickly. Pheonoligcal attributes such as starting date and leaf fall in urban areas likely being affected from heat island effect and related warming. Our study expressed that local and regional monitoring on phonological events and changes in Korea would be possible through MODIS data.

Analysis of seasonal environmental ecological flow at Han River tributary vulnerability points (한강 지류 취약지점에서의 계절별 환경생태유량 분석)

  • Yeon jung Noh;Seong joon Kim;Eun mi Hong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.146-146
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    • 2023
  • 우리나라의 하천은 도시의 급격한 산업화와 공업화로 인해 이수, 치수 목적을 중심으로 관리되어왔다. 그러나 최근 기후변화의 가속화와 댐과 같은 인공 구조물로 인해 하천의 수질 및 흐름이 위협받으면서 하천 환경개선에 대한 문제가 사회적으로 대두되고 있다. 하천의 생태기능은 하천에서 살아가는 각종 생물의 서식 조건을 유지함으로써 하천이 환경적으로 건강한 상태를 유지하도록 하는데 중요한 역할을 한다. 따라서 하천 환경개선을 위해서는 하천 생태기능 유지를 위한 최적 유량을 확보해야 한다. 일반적으로 하천의 생태기능을 보존하는데 필요한 최적 유량에 대한 평가에는 USGS(United States Geological Survey)에서 개발한 어류에 대한 유량과 서식지 가용성사이의 관계를 바탕으로 하는 물리적 서식처 모형 (Pysical HABitat SIMulation, PHABSIM)이 널리 사용되고 있다. PHABSIM은 가중가용면적(Weighted Useable Area, WUA)과 유량의 관계곡선을 산출하여 생태유량을 산정할 수 있게 한다. 본 연구에서는 최근 10년 동안 어류 건강성 평가에서 낮은 등급을 받은 탄천 대왕교 지점을 대상으로 PHABSIM을 이용한 어류의 계절별 최적 생태유량을 산정했다. 연구에 사용된 유량자료는 2012부터 2021년까지의 데이터가 사용되었다. 탄천의 대표 어종으로는 각 하천에서 우점종으로 선정된 Zacco platypus가 사용되었다. 각 연도별 그리고 계절별 하천 유량의 변화에 따른 환경생태유량 분석을 통해 제시된 각 하천의 최적 환경유지유량에 대한 결과는 한강권역 환경생태유량 산정 및 하천 관리를 위한 기초자료로 활용할 수 있을 것이다.

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기후변화에 의한 한반도 기후와 유출량의 변화

  • Lee, Dong-Gyu
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.37 no.1
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    • pp.8-12
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    • 2008
  • 기후변화가 한반도 지역기후와 유출량에 미치는 영향을 조사하기 위하여 지역기후모델과 수문모델을 이용하여 고해상도 한반도 70년 장기 지 역기후와 유출량을 생산하였다. 생산된 자료에 따르면 한반도의 미래 지상온도는 현재에 비하여 $1.5^{\circ}C$ 상승하고, 강수량은 0.2 mm $day^{1}$ 만큼 감소한다. 지상온도는 모든 계절에 상승하고, 강수는 초여름을 제외한 모든 계절에 감소한다. 미래의 연평균 강수량이 감소함에도 불구하고, 강수 강도는 증가하고, 집중호우 일수는 증가하였다. 봄과 겨울의 길이가 감소하고, 여름은 증가하며, 봄의 시작이 빨라진다. 금강유역의 유출량은 이수기에는 감소하고, 홍수기에는 증가하는 경향이 나타난다. 이와 같은 한반도의 미래 지역기후 변화로 인하여, 이수기의 물부족, 호우로 인한 재해 피해 증가, 개화시기와 식생군의 변화가 야기될 수 있다.

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Seasonal Fluctuation of Zooplankton Community in Asan Bay, Korea (아산만 동물플랑크톤 군집의 계절변화)

  • CHOI Keun-Hyung;PARk Chul
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.26 no.5
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    • pp.424-437
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    • 1993
  • About three fourths of total variability of zooplankton in Asan Bay was associated with season and the difference between inner bay and outer bay was relatively small. However, the differences in percent compositions of major taxa at inner bay and outer bay increased gradually with time, suggesting the change of ecosystem in this bay due to the human exploitation such as reclamation. Seasons of maximum abundances were different among the taxa but consistent for each taxon throughout the three survey years. Calanus sinicus and Acartia bifilosa showed maximum abundance in spring. Sagitta crassa, Paracalanus parvus, A. pacifica, Tortanus spinicaudatus, Corycaeus affinis and Decapoda larva were most abundant in summer. Labidocera euchaeta and Bivalve larva appeared most abundantly in fall. But in winter no taxon showed maximum. In general, low abundance with many species in fall, low abundance and few taxa in winter, increase in both number of taxa and abundance in spring, and high abundance and many taxa in summer were observed. A hypothesis for the observed patterns was suggested although more evidences were needed to support this.

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The Sources of Preservice Secondary Teachers' Explanations about Seasonal Changes Investigated with the Lakatosian Methodology (Lakatos의 방법론에 의한 예비 중등 교사의 계절 변화에 대한 설명의 근원 연구)

  • Oh, Jun-Young;Kang, Yong-Hee;Lee, Hyo-Nyong;Kim, Yong-Gi
    • Journal of the Korean earth science society
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    • v.27 no.4
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    • pp.374-389
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    • 2006
  • The purpose of this study was to investigate the alternative models of seasonal changes that preservice secondary teachers presented using the Lakatosian methodology. Participants included 74 undergraduate students who majored in science education within the college of education. Their responses to these questions revealed students' alternative models were inconsistent with scientific models. A great deal of this apparent inconsistency could be explained by assuming that the students used, in a consistent fashion, a alternative core belief on seasonal changes. This study also discussed the core beliefs and the possible sources held by preservice teachers in order to overcome their alternative models. The sources of alternative models may lie in the contents used in textbooks.