• 한국환경과학회지
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• 제27권3호
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• pp.155-165
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• 2018

Observations were conducted in Uiseong Binggye-ri Ice Valley of Korea, where a low temperature talus is located. The talus temperature at Ice Hole near the lower end of the talus remained at $0^{\circ}C$ until summer or autumn and averaged $-0.3^{\circ}C$ over 2 years. The talus temperature at Warm Hole was much higher than the external air temperature during autumn and winter. The outflow of warm air at Warm Hole begins in the late summer of fall. The direction of airflow through the talus surface was determined by the relationship between talus temperature and external air temperature. Annual variations in talus temperature and air exchange between the talus and the external environment can be divided into four periods. It was found that the airflow directions at Warm Hole and Ice Hole were not necessarily opposites. The outflows from the talus at Ice Hole and Warm Hole can occur simultaneously.

• Journal of Ecology and Environment
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• 제35권1호
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• pp.15-25
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• 2012

Time series of ocean climate indices and catch records were used to identify the alternation patterns of pelagic fish populations in relation to climate regime shifts. During 1910-2008, an orderly alternation of dominant pelagic fish groups was observed in the Tsushima Warm Current (TWC; Yellow Sea-East China Sea-East Sea/Japan Sea) and Kuroshio-Oyashio Current (KOC; Northwestern Pacific) regions. After the collapse of herring fishery in the late 1920s, the sardine (A group) dominated in the 1930s, 3 other species (C group; Pacific saury, jack mackerel, and anchovy) dominated in the 1950s-1960s, chub mackerel (B group) dominated in the 1970s, and then sardine (A group) dominated again during cool regime in the 1980s. As sardine biomass decreased in association with the climate regime shift that occurred in the late 1980s, catches of C group immediately increased after the regime shift and remained at high levels during warm regime in the 1990s. Alternations of dominant fish groups occurred 6 times between 1910 and 2008. The dominant period of the 7 species lasted for 10-20 years. The catch of Pacific sardine in the TWC and KOC regions showed a negative correlation with the catch of the other 5 species (Pacific herring, anchovy, jack mackerel, Pacific saury, and common squid), suggesting that the abundance of the 5 species is strongly affected by the abundance of Pacific sardine in relation to the climate regime shifts. The total catch level of the 7 species in the KOC region was generally higher than that in the TWC region before 1991 but was lower after 1992, suggesting that the fish populations in the Pacific side are shifted to the TWC region by zonal oscillation of the oceanic conditions in relation to the climate regime shift in the late 1980s.

• Journal of Ecology and Environment
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• 제31권1호
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• pp.45-67
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• 2008

Ocean climate variables ($1900{\sim}2005$), time series of catches ($1910{\sim}2005$) and body size data were used to assess the year-to-year and decadal scale fluctuations in abundance of the fish populations (Japanese sardine, anchovy, jack mackerel, chub mackerel, Pacific saury and common squid) that have spawning grounds in the East China Sea and its adjacent regions. A negative correlation between the abundance of pelagic fishes (e.g. jack mackerel) in the Tsushima Warm Current (TWC) region and the Kuroshio-Oyashio Current (KOC) region was attributed to the climatic modulation of larval transport and recruitment, which depends on the winter monsoon-induced drift, current systems, and spawning season and site. The changes in abundance and alternation of dominant fish populations in the two regions in the 1930s, 1970s, and late 1980s mirrored changes in the climate indices (ALPI, AOI and MOI). Oscillations in the decadal climate shifts between the two regions led to zonal differences in larval transport and recruitment, and hence differences in the abundance of the pelagic fish populations. During deep Aleutian Lows, as in the 1980s, larval transport from the East China Sea to the KOC region increases in association with the strong winter Asian monsoon, cool regime and increased volume transport of the Kuroshio Current systems, whereas during a weak Aleutian Low (as in the 1990s), larval transport to the TWC region increased in association with a weak winter Asian monsoon, a warm regime, and increased volume transport of the Tsushima current system. We postulate that the increased chub mackerel abundance in the TWC region and the decreased abundance in the KOC region in the 1990s are partly attributed to changes in recruitment and availability to the fishing fleets under the warm regime in the spawning and nursery grounds in the East China Sea in association with the quasi-steady state of mild winter monsoon in the 1990s. The fluctuations in chub mackerel and jack mackerel abundance are under the environment-dependant growth form, although the tropicalization was identified in the TWC region. The density-dependant growth form was found in Japanese sardine populations, but no tropicalization by fishing was identified in the long ($10{\sim}15$ year) periods of abundance despite their short ($3{\sim}4$ year) generation time, suggesting that the environment-dependant growth form drove the changes in abundance. Year-to-year and decadal scale variations in abundance and population structure of the Pacific saury responded to climate regime shifts (1976/1977, 1988/1989), suggesting that the fish is a key bio-indicators for changes in the ecosystem.

• 한국환경과학회지
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• 제21권12호
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• pp.1425-1433
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• 2012

Water temperature in the eastern part of the Yellow Sea (EYS) during winter (JFM) and summer (JJA) from 1964 to 2009 and Siberian High Pressure Index (SHI) and Arctic Oscillation index (AOI) during winter (JFM) from 1950 to 2011 were used to analyze long-term variation in oceanic and atmospheric conditions and relationship between winter and summer bottom water temperature. Winter water temperature at 0, 30 and 50 m had fluctuated highly till the late of 1980s, but after this it was relatively stable. The long-term trends in winter water temperature at both depths were separated with cold regime and warm regime on the basis of the late 1980s. Winter water temperature at 0m and 50m during warm regime increased about $0.9^{\circ}C$ and $1.1^{\circ}C$ respectively compared to that during cold regime. Fluctuation pattern in winter water temperature matched well with SHI and AOI The SHI had negative correlation with water temperature at 0 m (r=-0.51) and 50 m (r=-0.58). On the other hand, the AO had positive correlation with Winter water temperature at 0 m (r=0.34) and 50 m (r=0.45). Cyclic fluctuation pattern of winter water temperature had a relation with SHI and AO, in particular two to six-year periodicity were dominant from the early of the 1970s to the early of the 1980s. Before the late of 1980s, change pattern in winter water temperature at 0 and 50 m was similar with that in the bottom water temperature during summer, but after this, relationship between two variables was low.

• 한국기후변화학회지
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• 제7권1호
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• pp.49-57
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• 2016

In the present study, the time series of the number of days on which temperatures were not higher than $-5^{\circ}C$ in winter in Seoul was analyzed. The results showed a decreasing tendency until recently. Statistical change-point analysis was conducted to examine whether climate regime shifts existed in this time series. According to the results, the number of days on which temperatures were not higher than $-5^{\circ}C$ in winter in Seoul drastically decreased since 1988. Therefore, to find out the reason for the recent decrease in the number of days, differences between the means of large-scale environments in winder during 1988~2010 and those during 1974~1987 were analyzed. In all layers of the troposphere, anomalous anticyclones developed in regions around the Korean Peninsula and thus the Korean Peninsula was affected by westerlies or south-westerlies. This was associated with the recent a little further northward development of western North Pacific subtropical high. Therefore, environments good for warm and humid air to flow into the Korean Peninsula were formed. To examine whether relatively warm and humid air actually flowed into the Korean Peninsula recently, temperatures and specific humidity in all layers in the troposphere were analyzed and according to the results the Korean Peninsula showed warm and humid anomalies. In the analyses of sensible heat net flux and maximum temperatures at a height of 2 m that can be felt by humans, the East Asia Continent including the Korean Peninsula showed positive anomalies.

• 한국어류학회지
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• 제18권4호
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• pp.319-328
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• 2006

1971~2002년까지의 지난 32년간 장기간 시계열 자료를 통하여 겨울철 남해의 방어 어획량 변동양상을 계절별로 구분하여 조사하고, 이와 더불어 겨울철 한국 남부의 기상상황 및 남해의 해황 변화도 조사하여 장기간의 환경변화와 방어의 어획량 변동 사이의 대응관계에 대해서 살펴보았다. 겨울철 우리나라 남부의 기상변동을 살펴본 결과 1990년대에 들어서 기온이 상승하고 상대습도는 낮아지며 풍속이 많이 약화되는 특징들을 보이는 등 전체적으로 온난화 경향을 나타내고 있었고, 겨울철 남해의 50 m 수층 수온도 이 시기부터 뚜렷이 상승하고 있었다. 이와 관련하여 남해의 방어 어획량 변동양상을 계절별로 구분하여 조사한 결과 타 계절에 비해 특히 겨울철 생산량이 1990년대에 들어서부터 점차 증가하고 있었으며 방어의 주먹이원의 하나인 멸치의 어획량도 이 시기부터 증가하고 있었다. 이번 연구에서 조사한 기상 요인들을 포함한 환경 요인들과 겨울철 남해 방어 어획량 자료를 이용하여 상관분석을 실시한 결과 겨울철 방어 어획량의 증가는 겨울철 기온과 수온의 증가 그리고 멸치 어획량의 증가와 매우 밀접하게 연관되어 있다는 것을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권5호
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• pp.658-664
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• 2002

This study was conducted to determine a proper feeding regime for lactating Holstein cows during the warm season in Taiwan. In Feeding Trial, 21 lactating Holstein cows were randomly allotted into three feeding regimes in a Completely Randomized Design. The feeding regimes were roughage fed ad libitum along with concentrate fed either twice daily (2C) or four times daily (4C), and total mixed ration (TMR) for 8 weeks. No significant differences among the three feeding regimes were found in body weight changes, and intakes in terms of dry matter, crude protein and net energy. For milk yield and 4% FCM yield, 4C were higher than the other two feeding regimes (p<0.05). No significant differences were found in milk compositions or differences noted in the yields of the respective milk components. TMR was worse than 2C and 4C (p<0.05) in milk production efficiencies in terms of dry matter intake per kg milk yield, crude protein intake per kg milk protein yield, as well as dry matter intake, net energy intake and crude protein intake per kg 4% FCM yield. Three ruminally fistulated Holstein dry cows were randomly assigned into the same three feeding regimes in a 3${\times}$3 Latin Square Design. No significant differences were found among the feeding regimes in ruminal pH, ammonia nitrogen, total VFA concentration, molar percentages of VFA, and acetic acid: propionic acid ratio (C$_2$/C$_3$). Taken all together, roughage fed ad libitum and concentrate fed four times daily was the better feeding regime for lactating cows during the warm season in Taiwan.

• 대한지리학회지
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• 제46권3호
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• pp.277-290
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• 2011

본 연구에서는 장기간의 관측 자료를 분석하여 레짐이동에 따른 우리나라 여름철 강수의 특성변화 및 그 원인을 파악하였다. 우리나라 여름철 강수량의 시간적 변동을 분석한 결과, 1998년 이후 강수량의 변동 폭이 크게 증가하였다. 이는 장마 후 기간인 8~9월 강수량의 변동성 증가가 기여한 것으로 보이며, 6~7월의 강수량 역시 점차적인 증가 경향을 보였다. 강수량의 레짐이동에 따른 공간 분포의 변화는 1998년 이후 동아시아 전체에 걸쳐 밴드 형태의 강수량 증가 구역이 나타났으며, 8~9월에는 동아시아 지역 내에서 우리나라가 유일하게 큰 증가를 보였다. 특히 서울 및 경기 지역은 130mm 이상으로 강수량이 가장 크게 증가했다. 이는 우리나라 북쪽과 동쪽에 위치한 고기압성 흐름의 강화로 북쪽의 찬 공기와 남동쪽에서 불어오는 따뜻하고 습윤한 공기가 우리나라에서 수렴하게 되어 강수시스템 발달에 좋은 조건이 되기 때문인 것으로 나타났다. 우리나라 동쪽의 상층까지 발달한 키 큰 순압고기압은 동아시아와 북태평양의 해수면온도 상승에도 기여하여 온난한 공기의 유입이 우리나라 쪽으로 강화되었다.

• 한국환경과학회지
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• 제13권5호
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• pp.449-467
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• 2004

Interannual and decadal scale changes in body size of Pacific saury, catch and catch per unit effort were examined to investigate the environmental effects on the stock structure and abundance in the Tsushima Warm Current region. Interannual changes in thermal conditions are responsible for the different occurrence (catch) rates of sized group of the fish. Changes in body size due to environmental variables lead the stock to be homogeneous during the period of high abundance, while one of the reminder cohorts supports the stock during the period of low level of abundance. Migration circuits of two cohorts of saury stock are hypothesized on the basis of short life span and spatio-temporal changes of the stock structure in normal environmental conditions. Changes in upper ocean structure and production cycles by the decadal scale climate changes lead changes in stock structure and recruitment, resulting in the fluctuation of saury abundance. Hypothesized mechanism of the effects of climate changes on stock structure and abundance is illustrated on the basis of changes in thermal regime and production cycle.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2004년도 수산관련학회 공동학술대회 발표요지집
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• pp.169-171
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• 2004

Interannual and decadal scale body size of Pacific saury, catch and catch per unit effort were examined to investigate the environmental effects on the stock structure and abundance in the Tsushima Warm Current region. Interannual changes in thermal conditions are responsible for the different occurrence (catch) rates of sized group of the fish. Changes in body size due to environmental variables lead the stock to be homogeneous during the period of high abundance, while one of the reminder cohorts supports the stock during the period of low level of abundance. Migration circuits of two cohorts of saury stock are hypothesized on the basis of short life span and spatio-temporal changes in stock structure in normal environmental conditions. Changes in upper ocean structure and production cycles by the decadal scale climate changes lead changes in stock structure and recruitment, resulting in the fluctuation of saury abundance. Hypothesized mechanism of the effects of climate changes on the stock structure and abundance is illustrated on the basis of changes in thermal regime and production cycle.