• Title/Summary/Keyword: East Pacific

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The Intensification of Walker Circulation over the Past 15 Years from 1999 and Its Relation to TC Activity in the Western North Pacific

  • Choi, Jae-Won;Cha, Yumi;Kim, Jeoung-Yun
    • Journal of the Korean earth science society
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    • v.37 no.6
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    • pp.359-372
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    • 2016
  • The time-series of Walker circulation index (WCI) in this study shows the strengthening of the Walker circulation in recent years. To further understand the large-scale features related to the WCI strengthening, a difference between the averaged meteorological variables in two time periods 1999-2013 and 1984-1998 is analyzed. The difference in 850 hPa stream flows between the two periods shows that the anomalous easterlies (anomalous trade wind) are dominant due to the strengthening of anomalous anticyclonic circulations at the subtropical Pacific of both hemispheres. The difference between the averaged zonal atmospheric circulations over $5^oS-5^oN$ in the two periods confirms that upward flows are strengthened at the tropical western Pacific and downward flows are strengthened at the tropical central and eastern Pacific in recent years. It matches the WCI strengthening in recent years. The time-series of tropical cyclone (TC) genesis frequency from July to September shows that a mean TC genesis frequency from 1999-2013 decreases compared to that of the time period 1984-1998. The monsoon trough in the period 1984-1998 was located in the further east direction and stronger than that in the period 1999-2013. TCs in the recent period that are generated in further west than TCs in the past period moved from the west. Thus, the TC intensity along the coasts in East Asia becomes weaker in recent period. The intensification of Walker circulation in recent years is related to the weaker TC intensity in East Asia through strengthened anomalous anticyclones at the subtropical western Pacific.

Feeding Habits of the Pacific Herring Clupea pallasii in the Coastal Waters of the East Sea, Korea (한국 동해 연안해역에 출현하는 청어(Clupea pallasii)의 식성)

  • Son, Seung Hyun;Jeong, Jae Mook;Kim, Hyeon Ji;Kim, Kyung Ryul;Baeck, Gun Wook
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.2
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    • pp.224-228
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    • 2022
  • The feeding habits of the Pacific herring Clupea pallasii were examined based on 333 specimens collected from the coastal waters of the East Sea of Korea. Sampling was conducted in April, June, and September 2019 and February 2020. The total length of the C. pallasii ranged from 11.9 cm to 37.7 cm. Euphausiids (93.0%, index of relative importance, IRI), especially Euphausia, comprised the primary diet of the pacific herring, in addition to amphipods, copepods, and fishes. The dietary composition of C. pallasii showed non-significant differences by size. As body size of C. pallasii increased, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) tended to increase.

The New Landscape of Trade Policy and Korea's Choices

  • Petri, Peter A.
    • East Asian Economic Review
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    • v.17 no.4
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    • pp.333-359
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    • 2013
  • Two mega-regional negotiations are changing the landscape of Asia Pacific trade policy: an Asian track centered on ASEAN (the Regional Comprehensive Economic Partnership or RCEP), and a Trans-Pacific track centered on the Trans-Pacific Partnership (TPP) among 12 economies, including the United States, which Korea is expected to join. Modeling results suggest that both would generate substantial benefits for Korea and the global economy. From Korea's viewpoint, the agreements would establish new FTAs with China, Japan and smaller economies, improve the utilization of FTAs by permitting the regional cumulation of inputs, and help to upgrade some Korean FTAs to more rigorous standards. By participating in these agreements, Korea could also help to guide them toward inclusive, high-quality regional outcomes. As one of the region's most open and agile economies, Korea has a large stake in regional integration and would be well advised to pursue both tracks.

Dokha: An Emerging Public Health Issue as a Form of Tobacco Smoking in the Middle East

  • John, Lisha Jenny;Muttappallymyalil, Jayakumary
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.12
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    • pp.7065-7067
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    • 2013
  • Background: Tobacco use is one of the leading causes of preventable death across the world today and the smoking rates among men in the Arab world are amongst the highest in the world. Smoking of dokha, a traditional Arab tobacco is common in some of the Middle East countries such as the United Arab Emirates and Iran. This review focuses on the prevalence, pattern and health effects of dokha use in the Middle East. For this purpose an electronic search was performed in the following databases and websites: MEDLINE, EMBASE, Proquest and Google scholar up to December 2012. The search strategy was based on Internet search for the synonyms of dohka or midwakh. From the results of the review it emerged that younger people are the most common users of dokha. Hence effective outreach health education programs, targeting adolescents, especially school students before they take up the habit of smoking, may thus curb the emergence of the problem.

Calibration and Validation of the Estimated Chlorophyll a Derived from KOMPSAT/OSMI Data and Fisheries Application in the East China Sea

  • Suh Young-Sang
    • Journal of Environmental Science International
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    • v.14 no.10
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    • pp.911-917
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    • 2005
  • A comparison between the estimated chlorophyll a from OSMI, the SeaWiFS and the chlorophyll a measured from the research cruises of National Fisheries Research and Development Institute was made. The updated empirical algorithm for calibrating and validating of the estimated chlorophyll a in the East China Sea was formulated by relationship between the estimated chlorophyll a and the field one. The relationship between the chlorophyll a and the band ratio(nLw490/555) was still highest in the OSMI data after launching of KOMPSAT satellite. The distributions of OSMI chlorophyll a were compared with those of sea surface temperature, zooplankton biomass, and catch amounts of the Pacific mackerel in the East China Sea. In case of the relationships in specially winter seasons of 2002 and 2004, the zooplankton and the fish were totally depended on the distributions of SST than those of chlorophyll a.

Dominant Modes of the East Asian Summer Monsoon Using Equivalent Potential Temperature (상당온위를 사용한 동아시아 여름철 몬순의 6월 및 7월 주 변동 모드 분석)

  • Son, Jun-Hyeok;Seo, Kyong-Hwan
    • Atmosphere
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    • v.22 no.4
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    • pp.483-488
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    • 2012
  • The monsoon front lies on East Asian region, but it gradually propagates to the north during the boreal summer. The equivalent potential temperature (EPT) reveals the thermodynamical features of air masses and monsoon front. Therefore, this study considered the thermodynamical EPT and dynamical wind fields to clarify the peculiarity of East Asian summer monsoon (EASM) variations in June and July, respectively. Western North Pacific subtropical high (WNPSH) and Okhotsk sea high (OSH) both play the crucial role to interannual variations of EASM frontal activity and amount of rainfall. The OSH is important in June, but the WNPSH is key factor in July. Furthermore, the OSH (June) is affected by North Atlantic tripolar sea surface temperature (SST) pattern and WNPSH (July) is influenced by North Indian Ocean SST warming.

Strengthened Madden-Julian Oscillation Variability improved the 2020 Summer Rainfall Prediction in East Asia

  • Jieun Wie;Semin Yun;Jinhee Kang;Sang-Min Lee;Johan Lee;Baek-Jo Kim;Byung-Kwon Moon
    • Journal of the Korean earth science society
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    • v.44 no.3
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    • pp.185-195
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    • 2023
  • The prolonged and heavy East Asian summer precipitation in 2020 may have been caused by an enhanced Madden-Julian Oscillation (MJO), which requires evaluation using forecast models. We examined the performance of GloSea6, an operational forecast model, in predicting the East Asian summer precipitation during July 2020, and investigated the role of MJO in the extreme rainfall event. Two experiments, CON and EXP, were conducted using different convection schemes, 6A and 5A, respectively to simulate various aspects of MJO. The EXP runs yielded stronger forecasts of East Asian precipitation for July 2020 than the CON runs, probably due to the prominent MJO realization in the former experiment. The stronger MJO created stronger moist southerly winds associated with the western North Pacific subtropical high, which led to increased precipitation. The strengthening of the MJO was found to improve the prediction accuracy of East Asian summer precipitation. However, it is important to note that this study does not discuss the impact of changes in the convection scheme on the modulation of MJO. Further research is needed to understand other factors that could strengthen the MJO and improve the forecast.

Features of Korean Rainfall Variability by Western Pacific Teleconnection Pattern (서태평양 원격패턴에 따른 한국 4월 강수량의 변동 특성)

  • Choi, Jae-Won;Park, Ki-Jun;Lee, Kyungmi;Kim, Jeoung-Yun;Kim, Baek-Jo
    • Journal of Environmental Science International
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    • v.24 no.7
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    • pp.893-905
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    • 2015
  • This study analyzes the correlation between Western Pacific (WP) teleconnection pattern index (WPI) in April during 1954-2008 and rainfall amounts in the same month. Based on the results, it is identified that there have been strong positive correlations between central China, Korea and the southwestern part of Japan in the East Asian region. Through differences between 10 positive WP years and 10 negative WP years selected from the April WPI excluding ENSO years, it is found that rainfall amounts increase in April of positive WP years due to the following characteristics. Increases in rainfall amounts are evident in the East Asian middle latitudinal region where the positive correlation between the two variables is the highest and this is because anomalous southwesterlies are strengthened in the East Asian middle latitudinal region due to the spatial pattern of a south-low-north-high anomalous pressure system centered on this region that is made by anomalous anticyclones centered on the southeastern side of the region and other anomalous anticyclones centered on the northeastern side of the region. In addition, anomalous westerlies (jet) are strengthen in the upper troposphere of the East Asian middle latitudinal region and as a result, anomalous upward flows are strengthened in this region and thus anomalous warm air temperatures are formed in the entire level of the troposphere in the region. In addition to atmospheric environments, anomalous warm sea surface temperatures are formed in the seas in the East Asian middle latitudinal region to help the rainfall amount increases in the East Asian middle latitudinal region.

Correlation between the Pacific Decadal Oscillation and East/Japan Sea SST in the Autumn (가을철 동해 표층 수온과 태평양 순년 진동의 상관성 분석)

  • PAK, GYUNDO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.4
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    • pp.509-518
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    • 2019
  • Analyses with various Sea Surface Temperature (SST) products indicate that the interannual variability of the area-averaged SST in the East/Japan Sea (EJS) is well correlated to that of Pacific Decadal Oscillation (PDO) during 1979-2018, especially in the autumn. The regression analysis with the wind vectors at 200 hPa, where the strongest jet stream flows, suggests that the long-term variability of the intensity as well as the meridional movement of the jet stream are related to the coupling of the autumn EJS SST and PDO. When the axis of the jet stream moves poleward (equatorward) with its weakening (strengthening), both the EJS SST and North Pacific SST increase (decrease). This suggests that both the intensity and meridional movement of the jet stream are possibly related to the coupling of the autumn EJS SST and PDO. However, effects of a weak jet stream during the summer and the strong East Asian winter monsoon make weak coupling between the EJS SST and PDO.