간행물
한국지구과학회지 KCI 등재 The Journal of The Korean Earth Science Society
- 발행기관 한국지구과학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-6692 (Print)2287-4518 (Online)
- 수록기간 1979 ~ 2024
- 주제분류 자연과학 > 지구과학 자연과학 분류의 다른 간행물
- 십진분류KDC 450DDC 550
권호리스트/논문검색
제30권 제5호 (2009년 9월) 13건
1.
2009.09
구독 인증기관 무료, 개인회원 유료
In 2007, just after the recession of the Changma, anomalously long rainy period (from July 30 to August 15) occurred in Korea. To identify the cause of the sustained rainy period, we performed synoptic analysis and the associated air motions. The behavior of each air parcel trajectory associated with atmospheric motion was then investigated. As a result, three particular phenomena occurring at latitudes lower than 40˚N were discovered. First, a mass of relatively cold air, referred to as E, made a deep intrusion from 20˚N to 60˚N. Second, this intrusion was accompanied by another mass of air called dE. It was colder and drier than E and originated from the mid-troposphere over the tropical ocean. Third, dE and E rotated clockwise three times over a period of 17 days over the Northwestern Pacific and blocked the westerly waves imbedded in the zonal flow from propagating. Two additional phenomena were observed at latitudes higher than 40˚N. First, the cold core system, while approaching from the west with low geopotential values at its center, was stagnated over Shanxi China. It enhanced the northward intrusion of dE and E, and then diminished. The subsequent low system showed similar evolution as the first one. Second, a warm core anticyclone was formed over Lake Baikal, blocking the westerlies for 13 days and contributed to the persistent northward incursion of warm moist air. Moreover, a horizontally extended intrusion of upper level clouds from the tropics to 50˚N, which may be interpreted as a tropical plume, was found around the end of the period (from August 12 to 15, 2007) with successive tropical nights over Korea.
5,700원
2.
2009.09
구독 인증기관 무료, 개인회원 유료
When magnetotelluric (MT) data are obtained in the vicinity of the coast, the surrounding seas make it difficult to interpret subsurface structure, especially the deep part of the subsurface. We introduce an iterative method to correct the sea effect, based on the previous topographic correction method that removes the distortion due to topographic changes in seafloor MT data. The method first corrects the sea effect in observed MT impedance, and then inverts corrected response in a model space without the sea. Due to mutual coupling between the sea and the subsurface structure, the correction and inversion steps are iterated until the changes in each result become negligible. The method is tested for 1- and 2-D structures using synthetic MT data produced by 3-D forward modeling including surrounding seas. In all cases, the method closely recovers the true structure assumed to generate synthetic responses after a few iterations.
4,800원
3.
2009.09
구독 인증기관 무료, 개인회원 유료
The Yongdong basin developed during Early Cretaceous in the central part of the Korean Peninsula and bounded on the northwest and southeast by northeast trending mega-scale strike-slip Yongdong Fault. An 8 km thick succession of exclusively terrigeneous sediments can be grouped into two mega-sequences. In concert with the migration of depocenter, the upper sequence overlaps the lower and occupies northern part of the basin during basin evolution. Alluvial and lacustrine environments were predominantly formed from early to late stage of the basin formation. Several lines of evidence support that the basin was formed within intra-arc tectonic environments and destroyed by polyphase tectonic force. Schematic evolutionary diagram of the basin is proposed.
4,900원
4.
2009.09
구독 인증기관 무료, 개인회원 유료
This study intended to the optimal conservation method and to make an application scheme for the fossil locality of the Quaternary Hamori Formation at the northeastern coast of Mt. Songak. Many kinds of innumerable fossils are found from the Hamori Formation in the study area: Footprints of hominid, trace fossils of invertebrates, bird, artiodactyla, proboscidea, carnivores, unclassified footprints, and body fossils (arthropoda, gastropoda, mollusca, and plants). The formation has been outcropped and eroded out with innumerous fossils by the strong wave action of storm and typhoon. Korean government recognized the dangerous situation of the important fossils and decided to conserve the formation for the national heritage. Method D1 (conservation hall or museum on the fossil locality) may be the best way to protect the fossil locality from all the natural activities and to do the research, exhibition, education, and sightseeing together. The application of the geologic materials from the fossil locality should preferentially focus on the collection and research which should be accompanied by exhibition, education, and sightseeing. The application scheme may be stepped into three stages during 10 years: (1) systematic conservation and publicity during 2005-2007, (2) establishment of wellorganized museum during 2008-2010, and (3) international museum with the optimized roles 2011-2014.
4,000원
5.
2009.09
구독 인증기관 무료, 개인회원 유료
Measurements of atmospheric CO2 were made in the mountainous region of Srinagar-Garhwal, India (January to December 2006). Concentrations of CO2 averaged 393±4.9 ppm in 2006. Daily variations of CO2 values showed minimum during the daytime (376.2 ppm) and peaked in the morning/evening (410.1 ppm). At monthly intervals, the CO2 values varied from 367±11.14 (May) to 425.2±13.54 ppm (March). If divided on a seasonal basis, the values declined to minimum amounts in post-monsoon (389.9±9.0 ppm) and reached maximums during winter (397.1±11.6 ppm). Although phenology is significant in controlling CO2 levels, short-term changes cannot be explained without the anthropogenic perturbations (e.g., vehicular pollution and forest fires). The CO2 concentrations in Srinagar-Garhwal (393.4 ppm) were generally higher than those of other major monitoring locations around the world.
4,000원
6.
2009.09
구독 인증기관 무료, 개인회원 유료
Three species of Pseudolarix including P. japonica, P. sp. A, and P. sp. B, all belonging to Pinaceae, are systematically described from the Middle Miocene Duho Formation of the Yeonil Group based on the detached seminiferous scales. The presence of Pseudolarix in the Yeonil flora indicates that various kinds of Pinaceae did flourish during the Middle Miocene. The occurrence of Pseudolarix is the first record in the Korean Tertiary flora.
4,000원
7.
2009.09
구독 인증기관 무료, 개인회원 유료
Cupressinocladus sp. found from the upper part of the Jinju Formation of the Shindong Group, Korea is described here based on the newly found leafy shoots. This species is characterized by the branched leafy shoot with decussate scale leaves. The presence of Cupressinocladus in the Jinju Formation indicates that the Early Cretaceous flora-sites in Eastern Eurasia are in a close association with territories of the mixed-type floras. The finding of this species records the first report for the Nakdong flora.
4,000원
8.
2009.09
구독 인증기관 무료, 개인회원 유료
Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities (NH) are 2,000-20,000 cm-3, and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to 45 kms-1. The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than 3M⊙, which had been born near the Galactic plane.
4,200원
9.
2009.09
구독 인증기관 무료, 개인회원 유료
This study intended to collect data for evaluating the meteorological value of Upo Wetland which is the largest wetland in the downstream of Nakdong River. The observations were conducted in summer at the Upo Wetland and its surrounding paddy field that is the converted areas from a wetland to a paddy field. The following results are obtained: 1) The temperature of Upo Wetland area was 1˚C lower than the surrounding area during the day while it was a little higher during the night.; 2) The maximum wind speed in the Upo Wetland area was 3.5 m/s which is stronger than 1.6 m/s of its surrounding area. The south wind was observed in the farmland for most of the day while north winds and south winds alternated between day and night in Upo Wetland.; 3) In heat budget analysis, Upo Wetland was wasted in the form of latent heat rather than sensible heat in daytime.
4,000원
10.
2009.09
구독 인증기관 무료, 개인회원 유료
The tropopause fold event that took place on January 1, 1997 over mid-region on the Korean Peninsula is examined by means of a numerical simulation based on a Mesoscale Model (MM5). The purpose of this paper is to investigate the effects of moisture in reinforcing a tropopause fold linked to an explosive cyclone. Two types of simulations were carried out; 1) simulations for moist conditions in which full physical and dynamic processes are considered and 2) simulations for dry conditions in which cumulus parameterization and cloud microphysics process are excluded. The results of the moist condition simulations demonstrate that the intensity of the central pressure of the cyclone was overestimated compared with the observed values and that the location of the center and the pressure deepening rates (-17 hPa/12 hr) complied with the observed values. The potential vorticity (PV) anomaly on the isentropic surface at 305 K continued to move in a southeast direction on January 1, 1997 and thus created a single tube of tropopause fold covering the northern and the middle area of the Korean Peninsula and reaching the ground surface at 0300 UTC and 0600 UTC. The results of the dry condition simulations show that the tropopause descended to 500 and 670 hPa in 0300 and 0600 UTC, respectively at the same location for the moist condition simulation; however, there was no deep tropopause fold observed. A comparison of the simulated data between the moist and the dry conditions suggests that a deep tropopause fold should happen when there is sufficient moist in the atmosphere and significantly large PV in the lower atmosphere pulls down the upper atmosphere rather than when the tropopause descends itself due to dynamic causes. Thus, it is estimated that moisture in the atmosphere should have played a crucial role in a deep tropopause fold process.
4,900원
11.
2009.09
구독 인증기관 무료, 개인회원 유료
The early Ordovician graptolites from the upper part (Tumok Member) of the Mungok Formation of the Namaeri and Baeiljae sections at Yeongwol consist of five species belonging to five genera. They are Adelograptus cf. tenellus, Callograptus sp., Dendrograptus suni, Dictyonema sp., and Psigraptus jacksoni. Of these 5 species, Psigraptus is the most excellent index fossil for international correlation with the early Ordovician strata. Adelograptus cf. tenellus from the Mungok Formation of the Namaeri and Baeiljae sections is also recognized with especially short stipe relative to Adelograptus tenellus. Three graptolite zones (such as Adelograptus, Psigraptus, and Dendroid type zones) are correlated with those of Canada, Australia, and China, respectively. The upper part of the Mungok Formation is assigned to the late Tremadocian.
4,600원
12.
2009.09
구독 인증기관 무료, 개인회원 유료
This study examines the changes of an interdecadal circulation over the Asian continent to find cause of the surface warming in Siberia from 1958 to 2004. According to our study, there is a coherency between a long-term change of sea surface temperature in the Indian Ocean and the rapid increase of air temperature in Siberia since 1976/1977. In this study, we suggest that mean wind field changes induced by the positive sea surface temperature anomalies of the Indian Ocean since 1976/1977 are caused of inter-decadal variations in a large-scale circulation over the Asian continent. It also indicates that the inter-decadal circulation over the Asian continent is accompanied with warm southerly winds near surface, which have significantly contributed to the increase of surface temperature in Siberia. These southerly winds have been one of the most dominant interdecadal variations over the Asian continent since 1976/1977. In addition, we investigated the long-term trend mode of 850 hPa geopotential height data over the Asian continent from the Empirical Orthogonal Function (EOF) analysis for 1958-2004. In result, we found that there was an anomalously high pressure pattern over the Asian continent, it is called 'the Asian High mode'. It is thus suggested that the Asian High mode is another response of interdecadal changes of large-scale circulations over the Asian continent.
4,200원
13.
2009.09
구독 인증기관 무료, 개인회원 유료
In the equilibrium theory of tides by Newton, tide on the Earth is a phenomenon driven by differential gravity contributed both by the Sun and the Moon. Due to the direct link of the generic tidal effect to the oceanic tides, college students in the earth science education department are exposed to this theory through oceanography lectures as well as astronomy lectures. Common oceanography textbooks adopt a non-inertial reference frame fixed to the Earth in which the fictitious, centrifugal force appears. This has a potential risk to provide misconceptions among students in various aspects including the followings: 1) this is how Newton originally derived the equilibrium theory of tides, and 2) the tide is a phenomenon appearing only in rotating systems. We show that in astronomy, a much simpler description, which employs the inertial frame, is generally used to explain tides and thus causes less confusion. We argue that the description used in astronomy is preferable both in the viewpoints of simplicity and ease of interpretation. Moreover, on a historical basis, an inertial frame was adopted by Newton in Principia to explain tides. Thus, the description used in astronomy is consistent with Newton's original approach. We also present various astrophysical tides which do not comply with the concept of centrifugal force in general. We therefore argue that the description used in oceanography should be compensated by that in astronomy, due to its complexity, historical inconsistency and limited applicability.
4,200원
