• Atmosphere
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• v.28 no.3
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• pp.325-336
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• 2018

This study investigates robust features of interdecadal changes in the Northern hemisphere summer tropical-extratropical teleconnection occurred around the mid-to-late 1990s by analyzing four different reanalysis data for atmospheric circulation and temperature, two precipitation reconstructions, and two sea surface temperature (SST) data during the satellite observation era of 1980~2017. For the last 38 years, there has been a significant increasing trend in anticyclonic circulation at lower and upper troposphere and 2 m air temperature with wavenumber-5 Rossby wave structure in the Northern Hemisphere (NH) extratropics. The increase has been accompanied with the significant weakening and northward shift of jet stream over Eurasia and the North Pacific. It is further found that there has been a significant interdecadal shift occurred around the mid-to-late 1990s in the two distinct modes of tropical-extratropical teleconnection: Western Pacific-North America (WPNA) and circumglobal teleconnection (CGT) pattern. After mid-to-late 1990s, the WPNA has played more important role in modulating the extratropical atmospheric circulation and surface climate, which has been preferentially occurred during the El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) decaying or transition summer such as 1998, 2010 and 2016. During these summers, severe heat waves were occurred over many parts of the NH extratropics due to the combined effect of the increasing trend in the barotropic anticyclonic circulation and the significant WPNA across the NH. Although weakened, the CGT also contributed to some of hot summers over many parts of the NH extratropics such as 1999, 2000, 2008, 2011, and 2012 when weak to moderate La $Ni{\tilde{n}}o$ was persisted.

• Ocean and Polar Research
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• v.30 no.3
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• pp.313-324
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• 2008

In order to understand the variation of ENSO-related oceanic environments in the tropical and North Pacific Ocean, spatio-temporal variations of sea surface temperature anomaly (SSTA) and sea surface height anomaly (SSHA) are analyzed from distributions of complex empirical orthogonal functions (CEOF). Correlations among warm pool variation, southern oscillation index, and ocean surface currents were also examined with respect to interannual variability of the warm pool in western tropical Pacific. Spatio-temporal distributions of the first CEOF modes for SSTA and SSHA indicate that their variabilities are associated with ENSO events, which have a variance over 30% in the North Pacific. The primary reasons for their variabilities are different; SST is predominantly influenced by the change of barrier layer thickness, while SSH fluctuates with the same phase as propagation of an ENSO episode in the zonal direction. Horizontal boundary of warm pool area, which normally centered around $149^{\circ}E$ in the tropics, seemed to be expanded to the middle and eastern tropical regions by strong zonal currents through the mature phase of an ENSO episode.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2857-2870
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• 2015

Although the incidence of breast cancer in Asia remains lower than in North America, Western Europe, and Oceania, rates have been increasing rapidly during the past few decades, and Asian countries now account for 40% of breast cancer cases diagnosed worldwide. Breast cancer mortality has also increased among Asian women, in contrast to decreased mortality in Northern America, Western Europe, and Oceania. These increased rates are associated with higher prevalence of breast cancer risk factors (e.g., reduced parity, delayed childbirth, increased obesity) that have accompanied economic development throughout the region. However, Asian regions (western, south-central, south-eastern, and eastern) and countries differ in the types and magnitude of changes in breast cancer risk factors, and cannot be viewed as a single homogeneous group. The objective of this paper was to contrast the heterogeneous epidemiology of breast cancer by Asian regions and countries, and to suggest potential avenues for future research.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.539-550
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• 2009

This study found that tropical cyclones (TCs) formed for fall in 2007 over the western North Pacific were distributed in high-latitudes comparing to 56-year (1951-2006) climatological mean. The frequency and latitude of TC genesis became higher than 56-year climatological mean from September onward in 2007 and all the TCs that formed to the north of 20$^{\circ}$N was also distributed after September in 2007. These characteristics of TC genesis for fall in 2007 could be confirmed through analyzing various variables, such as a large-scale atmospheric circulation, outgoing longwave radiation (OLR), vertical zonal wind shear, and sea surface temperature (SST). On the other hand, a frequency of the TC that occurred to the north of 200N showed a clear interdecadal variation and its decreasing trend was distinctive in recent years. Its intensity was also weaker that TCs that did to the south of 20$^{\circ}$N. However, a latitude of TC genesis showed an increasing trend until recent years, whose variation was consistent with trend that through a SST analysis, warm SST went north in recent years.

• 한국해양학회지
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• v.6 no.2
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• pp.85-91
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• 1971

The origin of the Tsushima Current water was investigated with a discussion on the western North Pacific Central Water. The Tsushima Current water is formed by the mixing of the Kuroshio surface water and the East China Sea water. The area where the mixing takes place remarkably is found to be the marginal region of the continental shelf of the East China Sea at the depth from 100 to 200 meters.

• Economic and Environmental Geology
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• v.11 no.1
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• pp.11-20
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• 1978

This paper examines the seismicity of the offshore area of western Canada in the light of findings from a detailed study of an earthquake swarm which occurred in the area during November-December in 1971. The distribution of epicenters and focal mechanism solutions of a few main events suggest that the seismicity of the area may largely be interpreted in terms of plate interactions among the Pacific, Juan de Fuca, Explorer and North American plates. Differences between the patterns of seismicity along the transform fracture zones and at their junctions with the ridges were also observed.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.49-58
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• 2012

Through a statistical change-point analysis, this study found that Korea landfalling tropical cyclone (TC) frequency has increased rapidly since 1981. This increase is due to the following phenomenon. When anomalous cyclone is developed in the East Asian continent, anomalous anticyclone is reinforced in the western Pacific, which is related to the eastward shift of western North Pacific high, and thus anomalous southerly is formed to Korea from low-latitudes. This anomalous southerly plays an important role as steering flow in moving TCs toward Korea. To examine the cause of the development of anomalous cyclone in the East Asian continent, this study analyzed the water equivalent of accumulated snow depth during the preceding spring (March to May). As a result, less snow depth is observed in most regions of the East Asian continent than before 1981. Therefore, anomalous cyclone in the East Asian continent in summer can be reinforced by the land heating from the preceding spring and then the steering flow of anomalous southerly that moves TCs toward Korea can be also developed to Korea from low-latitudes in summer.

• Atmosphere
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• v.26 no.4
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• pp.711-716
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• 2016

The dynamical model forecasts using state-of-art general circulation models (GCMs) have some limitations to simulate the real climate system since they do not depend on the past history. One of the alternative methods to correct model errors is to use the canonical correlation analysis (CCA) correction method. CCA forecasts at the present time show better skill than dynamical model forecasts especially over the midlatitudes. Model outputs are adjusted based on the CCA modes between the model forecasts and the observations. This study builds a canonical correlation prediction model for subseasonal (June) precipitation. The predictors are circulation fields over western North Pacific from the Global Seasonal Forecasting System version 5 (GloSea5) and observed snow cover extent over Eurasia continent from Climate Data Record (CDR). The former is based on simultaneous teleconnection between the western North Pacific and the East Asia, and the latter on lagged teleconnection between the Eurasia continent and the East Asia. In addition, we suggest a technique for improving forecast skill by applying the ensemble canonical correlation (ECC) to individual canonical correlation predictions.

• 한국해양학회지
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• v.20 no.1
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• pp.12-21
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• 1985

In this paper, the most important oceangraphic phenomena of the summer season in the East China Sea are reviewed. The hydrographic conditions in the suface layer above the seasonal thermocline are under great influence from solar heating, fresh water runoff mainly from the Yangtze River, and summer wind fields. In the lower layer below the thermocline, several distinct water masses e.g. the Kuroshio surface water, the Western North Pacific Central Water and the Yellow Sea Bottom Cold Water are intruded in response to the adjustment of the field of mass to the various dynamical processes. The frontal mixing between the intruded Yellow Sea Bottom Cold. Water and the Western North Pacific Central Water takes place in the bottom layer over the continental shelf south off Cheju Is. This mixed water probably has mush influence on the water properties of the intermediate and bottom layer around Cheju Is. and the south coast of Korea.