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This study found that the passage frequency of tropical cyclones (TCs) affecting Korea has had negative correlations with the Pacific Decadal Oscillation (PDO) and the El Niño–Southern Oscillation (ENSO) since the early 1980s. To examine the actual combined effects of PDO and ENSO on the passage frequency of TCs affecting Korea, the positive PDO and ENSO years for 9 years and the negative PDO and ENSO years for 9 years were selected during the periods of 1951–1981 (pre‐1981) and 1982–2012 (post‐1981), and then the average difference between these two phases was analyzed. An analysis of anomalous stream flows at 500 hPa showed the formation of anomalous cyclonic circulations in an east‐to‐west direction from East Asia to the North Pacific both in the pre‐1981 and post‐1981 periods in the positive PDO and ENSO years. However, the anomalous cyclones in East Asia were stronger in the pre‐1981 period, whereas the anomalous cyclones in the North Pacific were stronger in the post‐1981 period. Consequently, China, Korea and the west of Japan were affected by strong anomalous northerlies in the pre‐1981 period, and the TC passage frequency was lower in these regions as a result. In the post‐1981 period, these countries were affected by anomalous northwesterlies or anomalous westerlies. [ABSTRACT FROM AUTHOR]

In the present study, a highly positive correlation between the western North Pacific tropical cyclone (TC) genesis frequency and the Southeast Asian summer monsoon (SASM) was found during the June–August period. In order to examine the cause of the positive correlation between the two variables, the 14 years with the highest SASM index (positive SASM years) and the 14 years with the lowest SASM index (negative SASM years) were selected from a total of 39 years (1977–2015) and the mean difference between the two periods was analysed. In the positive SASM years, more TCs were generated in most of the western North Pacific region and tended to move in a northerly direction from the far northeastern sea of the Philippines towards Korea via the East China Sea. In the negative SASM years, TCs moved westward from the eastern sea of the Philippine to the southern coast of China and the Indochinese Peninsula via the South China Sea. A similar result is found in further comparisons in which years with strong El Niño‐Southern Oscillations are removed. Anomalous westerlies from the Mascarene High moved eastward, thereby forming anomalous cyclonic circulations in the western North Pacific. Thus, the Mascarene High played a decisive role in strengthening anomalous cyclonic circulations in the western North Pacific. This finding was verified by examining various environmental factors that affected TC genesis and the correlation analyses between the 850‐hPa geopotential height and the western North Pacific TC genesis frequency during the June–August period in addition to an analysis of the velocity potential and divergent winds. [ABSTRACT FROM AUTHOR]

This study applied statistical change‐point analysis to the time series of the Changma retreat date (CRD) on the Korean Peninsula over a recent 30‐year period (1985–2014) and detected that the CRD has been delayed by about 10 days since 2000. The average CRD is July 14 for 1985–1999 and July 24 for 2000–2014. Corresponding to the CRD delay, the July rainfall is concentrated in the northern South Korea during 2000–2014, whereas tends to be intense along the southern coast during 1985–1999. The delayed CRD is associated with, in the lower and mid‐troposphere, a strengthened cyclonic circulation around Lake Baikal–eastern Sea of Japan and an enhanced anticyclonic circulation in East China Sea. Thus, northerlies from strengthened cyclones and anomalous southerlies from the enhanced anticyclones converge at the northern‐central Korean Peninsula. The anomalous anticyclone is associated with the strengthening of the western North Pacific subtropical high that has strengthened in meridional direction in the later epoch, supplying warm and moist air to Korean Peninsula. The result is verified by the enhanced warm and moist anomalous upward flows in the latitude where Korean Peninsula is placed. The delayed CRD in the latter epoch is related to the decreased spring snowfall over East Asia except for the vicinity of the Lake Baikal, which results in severely hot weather in the East Asia continent from spring to July. The continent heating from spring to July weakened (increases), the thermal gradient between continent and ocean, thereby forming a low‐pressure system on East Asia and a high‐pressure system in western North Pacific, resulting in the strengthening of Changma rain belt in July and delayed the Changma withdrawal. [ABSTRACT FROM AUTHOR]

ABSTRACT This study analysed the time series of tropical cyclone ( TC) frequency during October-December ( OND) for 32 years (1980-2011). There was a strong decreasing trend of TCs until recently, and the TC sharply decreased from 1996 after the statistical change-point analysis was applied to this time series. To investigate the cause of such recent decrease in TC genesis frequency, the differences ( TC activity and its relation to large-scale environments, and others) between the mean of the period from 1996 to 2011 and the mean of the period from 1980 to 1995 were analysed. TCs during the period 1996-2011 mainly occurred in the western region of tropical western North Pacific ( TWNP), whereas during the 1980-1995 period they mainly occurred in the eastern region of TWNP. In the analysis of differences periods in the 850 hPa and 500 hPa stream flows between the two periods, an anomalous huge anticyclone existed from the north Pacific to the TWNP, and an anomalous huge cyclone existed to the west of 125°E including the East Asian continent. In other words, this is a typical low-west-high-east pressure system that appears in East Asia during summer, and this anomalous pressure system pattern caused the low TC genesis frequency during the 1996-2011 period. The low-west-high-east anomalous pressure system pattern which has been strengthened recently in East Asia suggests that the East Asian winter monsoon ( EAWM) has weakened during the 1996-2011 period. As a result, the amount of snow depth decreased in many areas of the East Asian continent except for the North China and the ground heat net flux also increased in many areas. This weakening of the EAWM strengthened the anomalous huge anticyclone in the TWNP as well as in the central North Pacific, which caused the low TC genesis frequency during the OND in recent years. [ABSTRACT FROM AUTHOR]

ABSTRACT This study analysed the interdecadal variation of the South China Sea summer (June-September) monsoon ( SCSSM) in recent 32 years (1979-2010). The SCSSM showed a strengthening interdecadal variability starting from 1995, which was also verified in time series of precipitation and precipitable water averaged over the SCSSM domain. Thus, 32 years of total analysis period was divided into two: first half of past 16 years (1979-1994, hereafter 7994) and recent 16 years (1995-2010, hereafter 9510) thereby analysing a mean difference between 9510 and 7994 periods to determine causes of the strengthened SCSSM since the mid-1990s. The spatial distribution of difference in outgoing longwave radiation, precipitable water, and precipitation between the two periods showed a typical La Niña pattern. The pattern which occurred during La Niña event has been verified through analysis on differences in 850- and 200- hPa stream flows between the two periods. At 850 hPa, anomalous huge anticyclones were strengthened in the both hemispheres so that anomalous easterlies were strengthened in the equatorial central and western Pacific. As a result, the SCS was affected by anomalous southeasterlies. On the contrary, anomalous huge cyclones were strengthened in the both hemispheres at 200 hPa so that anomalous westerlies were strengthened in the equatorial western and central Pacific. This means that rising air from the tropical western Pacific since the mid-1990s was moved to the east and then Walker circulation, which was descended at the tropical central and eastern Pacific, was strengthened. Due to the strengthened Walker circulation, La Niña events have been more dominant than before in recent years and as a result of this, SCSSM was more strengthened than before. [ABSTRACT FROM AUTHOR]

The identification of pigments applied in ancient paintings is of great importance for art conservation and history. In this work, pigment samples from the 19th century Korean Buddhist painting (taenghwa) at the Hwangnyongsa temple were analyzed using two analytical techniques: portable X-ray fluorescence (XRF) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Portable XRF was used to obtain elemental information about the pigments applied in the Korean guardian Buddhist painting. The XRF results revealed the characteristic elements in the pigments that were commonly used in that period. The qualitative and non-destructive XRF analyses of pigment layers of the Buddhist painting were compared with results obtained using the micro-destructive ToF-SIMS technique. The ToF-SIMS spectra of the pigments showed characteristic elemental peaks such as Pb+, Cu+, Hg+, Al+, and hydrocarbon ions for the white, green, red, blue, and black areas in the positive ion mode and CO3−, OH−, S−, Cl−, and CnH− in the negative ion mode, respectively. The XRF and ToF-SIMS results show that the white, green, and red areas in the Buddhist painting were painted with lead white, malachite, atacamite, cinnabar, and mars red as single or mixed pigments. Smalt and carbon were used to depict the blue and black areas in the Buddhist painting, respectively. ToF-SIMS combined with complementary methods such as portable XRF provides important information about ancient painting materials on a sub-micrometer scale. Therefore, by combining these complementary techniques, a thorough characterization of each pigment can be obtained, allowing for a proper strategy for the restoration process. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, the variations of Australian summer monsoons ( AUSMs) over the last 30 years (1983-2012) were examined. The analysis period for a total of 30 years was divided into 15 years for 1983-1997 (8397) and 15 years for 1998-2012 (9812) to analyse interdecadal variations of AUSMs. The AUSM index ( AUSMI) generally showed negative values in the 8397 period while showing positive values in the 9812 period, indicating that clear interdecadal variations exist in the AUSMI over the last 30 years. Recently, AUSMs have been trending towards being reinforced. The precipitable water averaged in the area for defining the AUSMI has also shown a tendency to increase, until recently, along with the characteristics of interdecadal variations. To examine the cause of the recent reinforcement of AUSMs, differences in 850 hPa stream flows between the average of the 9812 period and the average of the 8397 period were analysed. Anomalous cyclones were located in the west of Australia and the South China Sea, and anomalous anticyclones existed in the central and eastern Pacific in both hemispheres. Because of these patterns of anomalous pressure systems, anomalous equatorial easterlies (anomalous trade winds) were reinforced. The 200 hPa stream flows showed patterns opposite to those of the pressure systems shown by 850 hPa stream flows. Because of these patterns of anomalous pressure systems, anomalous equatorial westerlies were reinforced. These results mean that the Walker circulations - in which air currents ascend in the northern region of Australia and the Maritime Continent and descend in the equatorial central Pacific - were reinforced further in the 9812 period. These changes may be related to the interdecadal changes in the Pacific Ocean, including the Pacific Decadal Oscillation and El Niño-Southern Oscillation. [ABSTRACT FROM AUTHOR]

ABSTRACT In this research, the multiple linear regression models for the prediction of the Changma onset in Korea have been developed. The predictors are based on correlation analysis between Changma onset dates over 30 years (1973-2002), and the winds and geopotential heights at high, middle, and low levels of the troposphere during the preceding 6 months (December to May). The clearest correlation was observed at 850 hPa geopotential height field in the preceding April among 6 months. The fundamental meaning of this model indicates that Changma in Korea comes earlier when the Mascarene high becomes languished and the tropical storms around India and western North Pacific subtropical high (WNPSH) become strengthened. The reliability of this model has been tested and proved by statistical cross-validation analysis, and additionally, has been analysed for differences in the 850 hPa stream flows for those years that Changma comes earlier and later. From the preceding April onwards, the Mascarene high tends to become weakened so that the cross-equatorial flow is strengthened along the African east coast. The cross-equatorial flow fortifies the tropical storms around Indian as it moves to the east. In the long run, the flow is influenced so that the WNPSH is more developed to the north, influencing Changma rain band to move north faster. To determine why Changma comes later in Korea, the water equivalent of accumulated snow depth (WEASD) difference between the late and early onset phases in the preceding April has been analysed. The result indicated that WEASD had a positive value for most East Asian regions. Since the snow reflects solar radiation by the Albedo effect, it decreases the difference in temperature between continents and oceans by decreasing the surface air temperature. The result has been confirmed by analysing the sensible heat net flux (SHTFL) difference between the two phases. In this way, small temperature gaps between continents and oceans weaken the WNPSH allowing Changma rain band to more slowly move north. [ABSTRACT FROM AUTHOR]

This study analyses the correlation between western Pacific (WP) teleconnection pattern index (WPI) in April and rainfall amounts in the same month during 1954-2008. On the basis of 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 El Niño-Southern Oscillation 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 strengthened in the upper troposphere of the East Asian middle latitudinal region. 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. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]