• Atmosphere
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• v.31 no.5
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• pp.563-576
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• 2021

The performance of East Asian summer monsoon is assessed for GC2 and GC3.1, which are climate change models of the current and next climate prediction system in the Korea Meteorological Administration (KMA), GloSea5 and GloSea6. The most pronounced characteristics of GC models are strong monsoon trough and the weakening of the Western North Pacific Subtropical High (WNPSH). These are related to the weakening of the southwesterly wind and resulting weak monsoon band toward the Korean Peninsula. The GC3.1 is known to have improved the model configuration version compared to GC2, such as cloud physics and ocean parameters. We can confirm that the overall improvements of GC3.1 against GC2, especially in pressure, 850 hPa wind fields, and vertical wind shear. Also, the precipitation band stagnant in the south of 30°N in late spring is improved, therefore the biases of rainy onset and withdrawal on the Korean Peninsula are reduced by 2~4 pentad. We also investigate the impact of initialization in comparison with GloSea5 hindcast. Compared with GCs, hindcast results show better simulation within 1 month lead time, especially in pressure and 850 hPa wind fields, which can be expected to the improvement of WNPSH. Therefore, it is expected that the simulation performance of WNPSH will be improved in the result of applying the initialization of GloSea6.

• Journal of Ecology and Environment
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• v.31 no.1
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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.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.25-26
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• 2005

• Atmosphere
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• v.34 no.3
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• pp.257-271
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• 2024

In 2023, the World Meteorological Organization released a report on climate conditions in Asia, highlighting the region's high vulnerability to floods and the increasing severity and frequency of extreme precipitation events. While previous studies have largely concentrated on broader-scale phenomena such as the Asian monsoon, it is crucial to investigate the substantial characteristics of extreme precipitation for a better understanding. In this study, we analyze the spatiotemporal characteristics of extreme precipitation during summer and their affecting factors by decomposing the moisture budgets within specific Asian regions over 44 years (1979~2022). Our findings indicate that dynamic convergence terms (DY CON), which reflect changes in wind patterns, primarily drive extreme rainfall across much of Asia. In southern Asian sub-regions, particularly coastal areas, extreme precipitation is primarily driven by low-pressure systems, with DY CON accounting for 70% of the variance. However, in eastern Asia, both thermodynamic advection and nonlinear convergence terms significantly contribute to extreme precipitation. Notably, on the Korean Peninsula, thermodynamic advection plays an important role, driven by substantial moisture carried by strong southerly mean flow. Understanding these distinct characteristics of extreme rainfall across sub-regions is expected to enhance both predictability and resilience.

• Atmosphere
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• v.28 no.4
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• pp.415-425
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• 2018

The roles of atmospheric heating formation and distribution on the global circulation are of utmost importance, and those are directly related to not only spatial but also temporal characteristics of monsoon system. In this study, before we clarify the characteristics of apparent heat source <$Q_1$> and moisture sink <$Q_2$>, comparisons of three reanalysis datasets (NCEP2, ERA-Interim, and JRA-55) in its global or regional patterns are performed to clearly evaluate differences among datasets. Considering inter-hemispheric difference of global monsoon regions, seasonal means of June-July-August and December-January-February, which is summer (winter) and winter (summer) in the Northern (Southern) Hemisphere are employed respectively. Here we show the characteristics of eight different regional monsoon regions and find contributions of <$Q_2$> to <$Q_1$> for the regional monsoon regions. Each term in apparent heat source and moisture sink is shown to come from the ERA-Interim dataset, since the ERA-Interim could be representative of three datasets. The NCEP2 data has a different characteristic in the ratio of <$Q_2$> and <$Q_1$> because it overestimates <$Q_1$> compared to the other two different datasets. The Australia monsoon has been performing better over time, while some regional monsoons (South America, North America, and North Africa) have been showing increasing data inconsistency. In addition, the three reanalysis datasets are getting different marching with time, in particular since the early 2000s over South America, North America, and North Africa monsoon regions. The recent inconsistency among the three datasets that may be associated with the global warming hiatus remains unexplored.

• Atmosphere
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• v.33 no.2
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• pp.125-154
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• 2023

Since the Korean Meteorological Society was organized in 1963, the climate dynamics fields have been made remarkable progress. Here, we documented the academic developments in the area of climate dynamics performed by members of Korean Meteorological Society, based on studies that have been published mainly in the Journal of Korean Meteorological Society, Atmosphere, and Asia-Pacific Journal of Atmospheric Sciences. In these journals, the fundamental principles of typical ocean-atmosphere climatic phenomena such as El Niño, Madden-Julian Oscillation, Pacific Decadal Oscillation, and Atlantic Multi-decadal Oscillation, their modeling, prediction, and its impact, are being conducted by members of Korean Meteorological Society. Recently, research has been expanded to almost all climatic factors including cryosphere and biosphere, as well as areas from a global perspective, not limited to one region. In addition, research using an artificial intelligence (AI), which can be called a cutting-edge field, has been actively conducted. In this paper, topics including intra-seasonal and Madden-Julian Oscillations, East Asian summer monsoon, El Niño-Southern Oscillation, mid-latitude and polar climate variations and some paleo climate and ecosystem studies, of which driving mechanism, modeling, prediction, and global impact, are particularly documented.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.203-215
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• 1998

The weed vegetion of the rice fields in south Korea was researched in terms of syntaxonomy and synecology. Total 186 releves were analyzed by the Zurich-Montpellier school's method. 10 syntaxa were recognized: Stellario-Alopecuretum amurensis ass. nov. hoc loco, Alopecuro-Ranunculetum scelerati Miyawaki et Okuda 1972, Hemistepto-Capsellietum bursa-pastoriae ass. nov. hoc loco, Oryza sativa-Echinochloa crusgalli community, Sagittario-Monochorietum plantaginea Miyawaki 1960, Cyperus iria community, Hyperico-Juncetum decipiens ass. nov. hoc. loco, Spirodela-Lemna paucicostata community, Lemno-Salvinetum natans Miyawaki et J. Tuxen 1960. The Oryzo-Echinochloion oryzoides Bolos et Masclans 1955 and the Alopecurion amurensis Miyawaki et Okuda 1972 are representative of the summer annual plant community and the winter annual plant community. It was emphasized that syntaxonomical and synecological study on the ruderal and segetal weed vegetation in Korea should be accomplished in consideration of bioclimatic condition of summer monsoon climate of Korean Peninsula.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.74-76
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• 2007

The modern foraminiferal distribution patterns and species diversity in surrounding seas of Korea are controlled by winter monsoon and characteristics of water masses. Abrupt climate change, Younger Dryas cold episode" is identified in Korea. The Younger Dryas is characterized by local extinctions of foraminifera. Several record-breaking climate phenomena observed in Korea, especially September, 2007.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.184-203
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• 2013

This study analyzes the variability of Korean summer rainfall associated with the tropical low-frequency oscillation using long-term observation data. From the EOF analysis, the first mode showed opposite phase between the South and the North Korea with the regime shift in rainfall variability since the mid-1990s. The summer precipitation over South Korea tends to increase in southern part during strong El Ni$\tilde{n}$o where the warm sea surface temperature extends to far eastern tropical Pacific. In weak La Ni$\tilde{n}$a, the increased precipitation directly influences from the western tropical Pacific to the mid-latitude. In June, the rainfall over South Korea is positively correlated with the Indian Summer Monsoon while in July, it is negatively correlated with the Western North Pacific Summer Monsoon. In August, highly negative correlation between the rainfall over South Korea and the Indian Summer Monsoon is found.

• Journal of the Korean earth science society
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• v.35 no.1
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• pp.88-94
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• 2014

The seasonal predictability of the intensity of the Northeast Asian summer monsoon is low while that of the western North subtropical high variability is, when state-of-the-art general circulation models are used, relatively high. The western North Pacific subtropical high dominates the climate anomalies in the western North Pacific-East Asian region. This study discusses the predictability of the western North Pacific subtropical High variability in the National Centers for Environmental Prediction Climate Forecast System (NCEP CFS). The interannual variability of the Northeast Asian summer monsoon is highly correlated with one of the western North Pacific subtropical Highs. Based on this relationship, we suggest a seasonal prediction model using NCEP CFS and canonical correlation analysis for Northeast Asian summer precipitation anomalies and assess the predictability of the prediction model. This methodology provides significant skill in the seasonal prediction of the Northeast Asian summer rainfall anomalies.