• Journal of the Korean Geographical Society
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• v.43 no.5
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• pp.681-700
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• 2008

In this study, the spatial and temporal patterns of changes in means and extreme events of temperature and precipitation across the Republic of Korea over the last 35 years (1973-2007) are examined. Over the study period, meteorological winter (December-February) mean minimum (maximum) temperature has increased by $+0.54^{\circ}C$/decade ($+0.6^{\circ}C$/decade), while there have been no significant changes in meteorological summer (June-August) mean temperatures. According to analyses of upper or lower $10^{th}$ percentile-based extreme temperature indices, the annual frequency of cool nights (days) has decreased by -9.2 days/decade (-3.3 days/decade), while the annual frequency of warm nights (days) has increased by +4.9 days/decade (+6.8 days/decade). In contrast, the increase rates of summer warm nights (+8.0 days/$^{\circ}C$) and days (+6.6 days/$^{\circ}C$) relative to changes in summer means minimum and maximum temperatures means are greater than the decreasing rates of winter nights (-5.2 days/$^{\circ}C$) and days (-4.3 days/$^{\circ}C$) relative to changes in winter temperatures. These results demonstrate that seasonal and diurnal asymmetric changes in extreme temperature events have occurred. Moreover, annual total precipitation has increased by 85.5 mm/decade particularly in July and August, which led to the shift of a bimodal behavior of summer precipitation into a multi-modal structure. These changes have resulted from the intensification of heavy rainfall events above 40mm in recent decades, and spatially the statistically-significant increases in these heavy rainfall events are observed around the Taebaek mountain region.

• The Journal of the Petrological Society of Korea
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• v.19 no.3
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• pp.167-180
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• 2010

The geochemical studies on the plutonic rocks of the Geochang, the central part of the Ryongnam massif, were carried out in order to constrain the petrogenesis and the paleotectonic environment. The objects of this study are dioritic rocks, biotite granite and hornblende granite. The modal compositions indicate that the dioritic rocks are quartz diorite, quartz monzodiorite, tonalite, biotite granites are granodiorite, granite and hornblende granites are granite, quartz monzonite, quartz syenite. These rocks belong to the calc-alkaline series. Especially, trace elements such as Sr, Nb, Sr, Ti are depleted, suggesting that these rocks are produced in the subduction zone related to calc-alkaline series. Also, the studied granitic rocks correspond to peraluminous and I-type. Chondrite-normalized REE patterns show that LREE are enriched much more than HREE, and have weak Eu(-) anomaly. It is similar to pattern of Jurassic granitoids in the South Korea. Total REE value of the biotite granite and hornblende granite ranges 76.21~137.05 ppm and 73.84~483.21 ppm, respectively, also $(La/Lu)_{CN}$ value ranges 9.61~36.47 and 7.17~21.85. It is suggest that studied rocks suppor their emplacement at active continental margin. Also, these rocks are derived from magma generated by partial melting of lower continental crust materials.