• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.65-71
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• 2000

The growth of Daphniphyllum macropodum at Mt. Naejang National Park(Naejang temple area) was investigated in connection with the climatic factors by the use of tree-ring analysis. A pair of cores was extracted from each of 18 trees in the D. macropodum community area near Younjabong for the analysis. The period of mater chronology based upon D. macropodum covers from 1915 to 1998. The growth rates of D. macropodum were very poor in the years 1920, 1932, 1934, 1937, 1942, 1946, 1964, 1969 and 1985, respectively. Response function was employed to understand the relationship between the growth of D. macropodum and climatic factors. The response function of the growth rates of D. macropodum indicated significant negative correlation with the precipitation of August and September. Poor growth of D. macropodum during the August and September nay be due to the frequent rain periods during the summer The heavy rain during the summer seems to decrease the solar radiation, which eventually caused the decrease of photosynthesis capacity. In conclusion, we hypothesize that the decrease of the photosynthesis rates during the rainy summer seasons may cause the slower growth of D. macropodum.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.55-61
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• 2003

In the year 2000 we culminated a successful five year investigation of climate change by completing a preliminary east-west transect across Mongolia. An earlier tree-ring study at Tarvagatay Pass, Mongolia indicated unusual warming during the 20th century similar to other paleo-investigations of the northern hemisphere. This record had represented one of the few tree-ring records for central Asia. New data from several sites in western Mongolia confirmed the preliminary temperature. The highest twenty-year growth period for the composite record is from 1973-1994. The western Mongolian record was significantly correlated with the Taimyr Peninsula and two northern hemisphere temperature reconstructions reflecting large-scale temperature patterns while showing some important regional differences. These differences should prove useful for climate models. We have also developed a millennial length temperature-sensitive record at the Solongotyin Davaa site (formerly Tarvagatay Pass) using relict wood and living trees. Conspicuous features over the last 1000 years are a century scale temperature decline punctuated by the end of the Little Ice Age in the late-1800s and 20th century warming. The record also shows a cold period early in the 12th century and warm intervals late in the 10th, early in the 15th and at end of the 18th centuries. Despite a limited sample size before 900 AD, the long Solongotyin Davaa record is useful in indicating severe cold events and suggests some cold intervals nearly as severe. These tree ring series, spanning much of the circumpolar northern treeline, have been compiled to create a long-term reconstruction of the Earth's temperature over centuries. The new chronology, in addition to its value as a detailed record of Mongolian climate, provides independent corroboration for such hemispheric and global reconstructions and their indications of unusual warming during the 20th century.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.49-55
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• 2000

The Yellow-Sand phenomena occurred during the period from l0C to 14C in Korea have been investigated using the historical record of the Koryosa. It is written as the "dust rain"or "mud" which means the falling down of dust from the sky. The authors have extracted 50 historical writings of dust rain from the Koryosa. The results show that the observation records concerning Yellow-Sand phenomenon for the period of Korea Dynasty (918~1392) are described with the scientific accuracy for the Yellow-Sand phenomena as the pure dust phenomena, the mixture of Yellow Sand with snow or rain, and the Yellow-Sand associated with fog or hail, etc. It is also found that the occurrence of Yellow-Sand phenomena was the incomprehensible natural phenomena such as Yellow-Sand were interpreted as a warning from the Heaven to the king and people of their fail in moral principles.in moral principles.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.47-54
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• 2003

Climate of Mongolia is a driven force on natural conditions as well as socio-economic development of the country. Due to the precariousness of climate conditions and traditional economic structure, natural disasters, specially disasters of meteorological and hydrological origin, have substantial effect upon the natural resources and socio-economic sectors of Mongolia. Mongolia's climate is characterized by high variability of weather parameters, and high frequency and magnitude of extreme climate and weather events. During the last few decades, climate of the country is changing significantly under the global warning. The annual mean air temperature for the whole territory of the country has increased by $1.56^{\circ}C$ during the last 60 years,. The winter temperature has increased by $1.56^{\circ}C$. These changes in temperature are spatially variable: winter warming is more pronounced in the high mountains and wide valleys between the mountains, and less so in the steppe and Gobi regions. There is a slight trend of increased precipitation during the last 60 years. The average precipitation rate is increased during 1940-1998 by 6%. This trend is not seasonally consistent: while summer precipitation increased by 11 %, spring precipitation decreased by 17. The climate change studies in Mongolia show that climate change will have a significant impact on natural resources such as water resources, natural rangeland, land use, snow cover, permafrost as well as major economic activities of arable farming, livestock, and society (i.e. human health, living standards, etc.) of Mongolia. Therefore, in new century, sustainable development of the country is defined by mitigating and adaptation policies of climate change. The objective of the presentation is to contribute one's idea in the how to reflect the changes in climate system and weather extreme events in the country's sustainable development concept.

• The Korean Journal of Quaternary Research
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• v.15 no.2
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• pp.83-91
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• 2001

The environmental change during the upper Holocene was restored at Kimpo alluvial plain on the left bank of Han-river near the Yellow Sea according to the results of pollen analysis and carbon dating, based on the sea-level change from Ilsan area. Pollenzone I (5.8~7.0 m.a.s.l.) was the period of AP-dominance, including mostly Alnus. Study area was under the lagoon or swamp environment influenced by Flandrian transgression during 5,000~3,200 BP. Pollenzone II (7.0~7.4 m.a.s.l.) was the period of Spore & NAP-dominance. It represents that the vegetational environment was changed to drier condition by falling underwater surface caused by sea-level regression, and influenced by human activity during 3,200~2,300 BP. Subzone I a represented the characteristics of the climax of transgression. During subzone I b, herbs with the dominant Alnus were increased gradually, and it was correlated to the stagnation of high sea-level. Subzone II a was the dominant period of Spore by the gradual falling of sea-level. After that, the study area in swamp was emerged to the lowland by the fallen sea-level and herbs, especially Gramineae increased suddenly during Subzone II b. The sudden increase of NAP such as Artemisia, Chenopodiaceae and Umbelliferae with Gramineae during this period indicates the beginning of agriculture at this study area.

• The Korean Journal of Quaternary Research
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• v.23 no.1
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• pp.42-53
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• 2009

In response to the abrupt climate change in recent years, atmosphere, ocean and cryosphere are reported to be altered. In addition to these changes, the land surface is also gradually changing and its impact on the global climate may not be negligible. The land surface change impacts the global climate via two ways, the biogeochemical and biophysical feedbacks. The biogeochemcial change in the land surface modifies the atmospheric trace-gas concentrations through a change in photo synthesis, while biophycal changes of the land surface alters the surface albedo, which influences the amount of the short wave radiative heat fluxes. There are many examples in the past that the change in land surface greatly influences the global climate change. The recent IPCC report has suggested that the climate change will occur rather abrubtly in the near future. In order to predict the future climate accurately, the impact of the land surface change is fully considered.

• Journal of The Geomorphological Association of Korea
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• v.27 no.1
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• pp.33-45
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• 2020

A number of unconsolidated deposits, consisting of a layer of gravels and silt, are found in Dangjeong-ri, Seocheon-gun in the western coast. From below in the stratigraphic sequence, the gravel layer ranging up to a maximum thickness of about 2 meters is interpreted as being formed by fluvial processes of an old channel (Dangjeong S.), and the overlying silt or sandy silt layer of 2 to 3 thickness meters is assumed to be emerged paleo-tidal sediments which was deposited in low tidal-energy environments. As the results of rock surface IRSL datings, the depositional ages of gravels are confirmed as ca. 78,000 ~ 83,000 years BP, indicating that the layer was formed in response to a high-stand sea level of MIS 5a along the Dangjeongcheon estuary. It is presumed that the relative height of 4.5 meter between the altitude of the stream bed (9.5 m) and the altitude of the bedrock boundary in the gravel layer (14 m) indicates the uplift amount since deposition. Paleo-sedimentary environments and an altitude of paleo-shoreline in the study area will be discussed with additional age dating focused on the silt layer.

• The Korean Journal of Quaternary Research
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• v.16 no.1
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• pp.17-27
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• 2002

Analysis of No. 199∼145 cross-sections set up by the Ministry of Construction (1978) in the middle reaches of the Sumjin River around Sunchang, Daegang, and Goksung areas have been done for delineating the changes In fluvial geomorphic features. The entire river-bed in the study area has been considerably degraded since 1978. In some cross-sections, the thalweg shillings are observed. Two aspects are responsible for the erosion-dominant environment. First, flow velocity has been increased. Human activities including wetland destruction, ex-channel destruction and artificial levee construction reduced the channel width, and fixed the channel geometry. This has resulted in increase of the water velocity. Pebble and granule∼coarse sand are prevailing on the river-bed, indicate the high speed of the currents. Second, aggregate has been intensively mined during 1980s∼1990s around the areas. Especially, in the right side of the cross-sections No. 188∼187 and the left side of the cross-section No. 155, erosion toward under the artificial levee is remarkable. This can be led to bank failure in case of heavy rainfall.

• The Korean Journal of Quaternary Research
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• v.4 no.1
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• pp.15-26
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• 1990

Narrow (10-20 km wide) and steep (0.3-$2.4^{\circ}$) continental shelf off the eastern coast of Korea is covered with terrigenous clastic sediments reflecting the Holocene fluctuation of sea level. Surface sediments on the inner shelf consist of muddy sand and sandy mud with some gravels near the coast. However, sand or muddy sand, shell fragments and well rounded gravels occur near the edge of continental shelf at the depth of about 130-l50m. The coarse sediments near the shelf edge seem to be the relict or palimpsest sediments deposited under the nearshore environment during the low-stand or sea level due to so-called the Wisconsinan glaciation. Distribution of recent sediments near the coast and the inner shelf may reflect the affect of waves and currents precluding the deposition of fine sediment near the coast and on the shallow portion of shelf. Eastern Korean Warm Current also nay have played an important role to the transport and distribution of fine sediments from the south.

• Journal of The Geomorphological Association of Korea
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• v.24 no.2
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• pp.27-40
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• 2017

This study tries to analyze topographic distribution and characteristics of as well as formative age and incision rate of fluvial terraces in Danyang River on western side and Geum River on eastern side of the northern Sobaek Mountains and to estimate geomorphic development during the late Quaternary in the mountains regarded as one of the uplift axes in the Korean Peninsula. OSL age dating shows that the fluvial terrace I with an altitude above riverbed of approximately 7~13 m in Danyang River has a formative age of approximately 18 ka (MIS 2) and incision rate in the river is approximately 0.156~0.194 m/ka based on the age. Altitudes above riverbed of the fluvial terrace I in Geum River range from approximately 7 to 14 m and the terrace is thought to be older than 70 ka based on age result from aeolian sediments above the terrace deposits, suggestive of an incision rate less than approximately 0.10 m/ka. These results indicate lower uplift rate in the northern Sobaek Mountains than in the Taebaek Mountains. Moreover, it can be suggested that the northern Sobaek Mountains has experienced asymmetric uplift during the late Quaternary, because the river on western side of the northern Sobaek Mountains shows greater uplift rate than the eastern side river does. Low incision rate in Geum River can be attributed to low altitude of the river basin with little difference in altitude from the base level as well as to gentle river slope due to influence of Nakdong River.