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61.
Woodon Jeong Constantinos Tsingas Mohammed S. Almubarak 《Geophysical Prospecting》2020,68(5):1523-1539
A number of deblending methods and workflows have been reported in the past decades to eliminate the source interference noise recorded during a simultaneous shooting acquisition. It is common that denoising algorithms focusing on optimizing coherency and weighting down/ignoring outliers can be considered as deblending tools. Such algorithms are not only enforcing coherency but also handling outliers either explicitly or implicitly. In this paper, we present a novel approach based on detecting amplitude outliers and its application on deblending based on a local outlier factor that assigns an outlier-ness (i.e. a degree of being an outlier) to each sample of the data. A local outlier factor algorithm quantifies outlier-ness for an object in a data set based on the degree of isolation compared with its locally neighbouring objects. Assuming that the seismic pre-stack data acquired by simultaneous shooting are composed of a set of non-outliers and outliers, the local outlier factor algorithm evaluates the outlier-ness of each object. Therefore, we can separate the data set into blending noise (i.e. outlier) and signal (i.e. non-outlier) components. By applying a proper threshold, objects having high local outlier factors are labelled as outlier/blending noise, and the corresponding data sample could be replaced by zero or a statistically adequate value. Beginning with an explanation of parameter definitions and properties of local outlier factor, we investigate the feasibility of a local outlier factor application on seismic deblending by analysing the parameters of local outlier factor and suggesting specific deblending strategies. Field data examples recorded during simultaneous shooting acquisition show that the local outlier factor algorithm combined with a thresholding can detect and attenuate blending noise. Although the local outlier factor application on deblending shows a few shortcomings, it is consequently noted that the local outlier factor application in this paper obviously achieves benefits in terms of detecting and attenuating blending noise and paves the way for further geophysical applications. 相似文献
62.
Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests
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Heon‐Joon Park Jeong‐Gon Ha Sun‐Yong Kwon Moon‐Gyo Lee Dong‐Soo Kim 《地震工程与结构动力学》2017,46(14):2301-2316
This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
63.
Kim Suk Hyun Ra Kongtae Kim Kyung-Tae Jeong Hyeryeong Lee Jihyun Kang Dong-Jin Rho Taekeun Kim Intae 《Ocean Science Journal》2019,54(4):673-684
Ocean Science Journal - Trace elements (Mn, Fe, Co, Ni, Cu, Zn, etc.) are essential micronutrients for marine organisms and are thus related to major issues in the ocean, such as climate change,... 相似文献
64.
Growth,feeding and ecological roles of the mixotrophic and heterotrophic dinoflagellates in marine planktonic food webs 总被引:4,自引:0,他引:4
Hae Jin Jeong Yeong Du Yoo Jae Seong Kim Kyeong Ah Seong Nam Seon Kang Tae Hoon Kim 《Ocean Science Journal》2010,45(2):65-91
Planktonic mixotrophic and heterotrophic dinoflagellates are ubiquitous protists and often abundant in marine environments. Recently many phototrophic dinoflagellate species have been revealed to be mixotrophic organisms and also it is suggested that most dinoflagellates may be mixotrophic or heterotrophic protists. The mixotrophic and heterotrophic dinoflagellates are able to feed on diverse prey items including bacteria, picoeukaryotes, nanoflagellates, diatoms, other dinoflagellates, heterotrophic protists, and metazoans due to their diverse feeding mechanisms. In turn they are ingested by many kinds of predators. Thus, the roles of the dinoflagellates in marine planktonic food webs are very diverse. The present paper reviewed the kind of prey which mixotrophic and heterotrophic dinoflagellates are able to feed on, feeding mechanisms, growth and ingestion rates of dinoflagellates, grazing impact by dinoflagellate predators on natural prey populations, predators on dinoflagellates, and red tides dominated by dinoflagellates. Based on this information, we suggested a new marine planktonic food web focusing on mixotrophic and heterotrophic dinoflagellates and provided an insight on the roles of dinoflagellates in the food web. 相似文献
65.
66.
The climate sensitive analysis of potential climate change on streamflow has been conducted using a hydrologic model to identify hydrologic variability associated with climate scenarios as a function of perturbed climatic variables (e.g. carbon dioxide, temperature, and precipitation). The interannual variation of water resources availability as well as low flow frequency driven by monsoonal time shifts have been investigated to evaluate the likelihood of droughts in a changing climate. The results show that the timing shift of the monsoon window associated with future climate scenarios clearly affect annual water yield change of ? 12 and ? 8% corresponding to 1‐month earlier and 1‐month later monsoon windows, respectively. Also, a more severe low flow condition has been predicted at 0·03 m3/s as opposed to the historic 7Q10 flow of 1·54 m3/s given at extreme climate scenarios. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
67.
Climate Dynamics - In this study, we carried out an attribution analysis that quantitatively assessed relative contributions to the observed temperature anomalies associated with strong and weak... 相似文献
68.
Dongseon Kim Seung Ho Baek Dong-Young Yoon Kyung-Hee Kim Jin-Hyun Jeong Pung-Guk Jang Young-Ok Kim 《Ocean Science Journal》2014,49(3):251-264
A new water quality index for evaluating the water quality of Jinhae Bay and Gwangyang Bay was developed. Four water quality parameters were selected as water quality indicators for the water quality index: dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), chlorophyll-a (Chl-a), and dissolved oxygen (DO). Reference levels of DIN, DIP, and Chl-a were determined as 6.22 μmol L?1, 0.38 μmol L?1, and 2.32 μmol L?1, respectively, on the basis of a long-term dataset that was collected monthly in the Korea Strait over a period of seven years (2006–2012). The water quality index established for Jinhae Bay and Gwangyang Bay is (bottom DO grade × 0.33) + (surface Chl-a grade × 0.33) + (surface DIN grade × 0.17) + (surface DIP grade × 0.17). On the basis of a three-year observation, the water quality of Jinhae Bay was classified as “good” in winter and spring, “poor” in summer, and “fair” in autumn and exhibited large spatial variation, with the lowest-quality water observed in Masan Bay. The water quality of Gwangyang Bay was classified as “good” in winter, “fair” in spring, “poor” in summer, and “fair” in autumn. Unlike Jinhae Bay, the water quality of Gwangyang Bay exhibited minimal spatial variation. In both bays, water quality among the four seasons was worse during summer. It is essential that a survey for water quality evaluation be conducted during summer. 相似文献
69.
Byung-Kwon Moon Daeok Youn Rokjin J. Park Sang-Wook Yeh Won-Mo Kim Young-Ho Kim Jaein I. Jeong Jung-Hun Woo Eul Gyu Im Chang-Keun Song 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(4):345-351
We examine the meteorological responses due to the probable eruption of Mt. Baekdu using an off-line Climate-Chemistry model that is composed of the National Center for Atmospheric Research (NCAR) Climate Atmosphere Model version 3 (CAM3) and a global chemistry transport model (GEOS-Chem). Using the aerosol dataset from the GEOS-Chem driven by GEOS-5 meteorology, experiment and control simulations of the climate model are performed and their meteorological differences between the two simulations are analyzed. The magnitudes of volcanic eruption and column injection height were presumably set to 1/200 of the Mt. Pinatubo eruption and 9 km, respectively. Significant temperature drop in the lower troposphere (850 hPa), which is mainly due to a direct effect of prescribed volcanic aerosols from Mt. Baekdu, has been simulated up to about ?4 K. The upper atmosphere (150 hPa) right above the volcano, however, shows significant warming due to the absorption of the infrared radiation by volcanic aerosols. As a result of the volcanic eruption in the climate model, wave-like patterns are shown in both the geopotential height and horizontal wind. The changes in the lower atmospheric temperature are well associated with the modification of the atmospheric circulation through the hydrostatic balance. In spite of limitations in our current simulations due to several underlying assumptions, our results could give a clue to understanding the meteorological impacts from Mt. Baekdu eruptions that are currently attracting considerable public attention. 相似文献
70.
Sung Won Kim Sanghoon Kwon Hee Jae Koh Keewook Yi Youn-Joong Jeong M. Santosh 《Gondwana Research》2011,20(4):865-889
This study presents sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon ages, and whole-rock chemical and isotopic (Sr-Nd) compositions of representative Triassic plutons from South Korea. The plutons from the Gyeonggi massif (Hongseong, Namyang, Yangpyeong and Odesan), the central Okcheon belt (Baeknok and Yongsan), and the Yeongnam massif (Sangju, Gimcheon, Hamyang and Macheon) yield zircon U–Pb ages of ca. 232–226 Ma, 227–226 Ma, and 240–228 Ma, respectively. Among the Triassic plutonic suite in South Korea, those within the Gyeonggi massif are dominated by granite, syenite, monzonite, monzodiorite and gabbro. Plutons within the Okcheon belt are mainly by granite to quartz monzodiorite. The Yeongnam massif mainly incorporates granite to granodiorite and minor monzodiorite intrusions. The geochemical signatures of the Triassic plutons are characterized by Ta–Nb troughs, depletion of P and Ti, and enrichment of LILE. Most plutons except Macheon monzodioritic pluton show high initial 87Sr/86Sr ratios (0.708248–0.714678) and strongly negative εNd(T) (− 20.3 to − 7.7) values, suggesting contribution from middle to upper crust. In contrast, the Macheon monzodioritic pluton in the Yeongnam massif shows relatively low initial 87Sr/86Sr ratios (0.706547-0.706629) and negative εNd(T) (− 4.43 to − 3.62) values. The Middle Triassic syenite–monzonite–granite–gabbro series in and around the Gyeonggi massif possess high-K calc-alkaline and shoshonitic affinity suggesting a post-collisional magmatic event following the Permo–Triassic collision between the North and South China blocks. The Triassic plutons in the Yeongnam massif and the Okcheon belt, together with a Permian Yeongdeok pluton in the Gyeongsang basin, show features typical of high- to medium-K calc-alkaline magmatism with LREE and LILE enrichments. This together with a depletion of Y and HREE suggests their formation in a subduction setting. Our results provide robust evidence to consider the Gyeonggi massif as an extension of the Qinling–Dabie–Sulu belt between the North and South China blocks in central China. The Okcheon belt and Yeongnam massif in South Korea, together with the continental margin of South China, are marked by a common Permian to Triassic magmatic episode, probably related to the paleo-Pacific slab subduction. 相似文献