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921.
To more correctly estimate the error covariance of an evolved state of a nonlinear dynamical system, the second and higher-order
moments of the prior error need to be known. Retrospective optimal interpolation (ROI) may require relatively less information
on the higher-order moments of the prior errors than an ensemble Kalman filter (EnKF) because it uses the initial conditions
as the background states instead of forecasts. Analogous to the extension of a Kalman filter into an EnKF, an ensemble retrospective
optimal interpolation (EnROI) technique was derived using the Monte Carlo method from ROI. In contrast to the deterministic
version of ROI, the background error covariance is represented by a background ensemble in EnROI. By sequentially applying
EnROI to a moving limited analysis window and exploiting the forecast from the average of the background ensemble of EnROI
as a guess field, the computation costs for EnROI can be reduced. In the numerical experiment using a Lorenz-96 model and
a Model-III of Lorenz with a perfect-model assumption, the cost-effectiveness of the suboptimal version of EnROI is demonstrated
to be superior to that of EnKF using perturbed observations. 相似文献
922.
Hyeong Soo Kim Jin-Han Ree Jeongmin Kim 《International Journal of Earth Sciences》2012,101(2):483-498
The deformed and metamorphosed middle Pennsylvanian to Early Triassic (?) rocks of the Pyeongan Supergroup, occurring in northeastern flank of the Paleozoic Taebaeksan Basin, east central South Korea, record the impact of the Late Permian–Triassic Songrim (Indosinian) collisional orogeny in the eastern Eurasia margin. Analysis of meso- and microstructures and their relationship with porphyroblast growth has revealed that these metasedimentary rocks were affected by four deformation events (D1–D4). During the polyphase deformations, successive foliations with alternately steep (S1 and S3) and flat-lying (S2 and S4) orientations were produced with growth of chloritoid, andalusite and kyanite porphyroblasts during D1 and D2, and growth of garnet, staurolite and andalusite porphyroblasts during D3 and D4. SHRIMP U–Pb detrital zircon ages (330–310 Ma) from metapelites in the oldest unit of the Pyeongan Supergroup in the study area, combined with the previous data on sandstone compositions, indicate magmatic activity that was contemporaneous with the initial deposition of the Pyeongan Supergroup. This also suggests that the Pyeongan Supergroup was deposited in an arc-related foreland basin at an active continental margin during the Late Carboniferous and Permian time. Two contractional deformation events (D1 and D3) and two events related to gravitational flattening (D2 and D4), along with Barrovian-type medium-pressure regional metamorphism, may have resulted from the Late Permian–Triassic Songrim orogeny, related to collision between the North and South China blocks and/or collision between the Eastern Eurasia margin and the proto-Japan terrane. 相似文献
923.
924.
Kitirote Wantala Eakkachai Khongkasem Nuthakarn Khlongkarnpanich Suthipong Sthiannopkao Kyoung-Woong Kim 《Applied Geochemistry》2012
This work focused on the removal from water of arsenate in the 100 to 500 μg/L range using Fe-RH-MCM-41 immobilized on GAC by a colloidal impregnation method. A Response Surface Method (RSM) based on the Box–Behnken Design (BBD) was used to evaluate the effects of pH, adsorbent loading, and initial arsenate concentrations. The thermal stability of Fe-RH-MCM-41/GAC was greater than 460 °C because Fe-RH-MCM-41 and epoxy resin covered the GAC, preventing GAC weight loss. The rate and capacity for arsenate adsorption on Fe-RH-MCM-41/GAC were higher than for GAC. The effects of pH, adsorbent loading, and initial arsenate concentration showed significant effects on efficiency, in terms of percent arsenate removal. Significant interaction occurred as positive effects between arsenate and arsenate concentrations, and pH and arsenate concentrations, and as negative effects between pH and pH, adsorbent loading and adsorbent loading, and adsorbent loading and arsenate concentrations. 相似文献
925.
The concentrations of trace elements in groundwater and seawater were measured in a coastal embayment (Bangdu Bay) of a volcanic island (Jeju) off the southernmost coast of Korea in August and December of 2009. The concentrations of trace elements (Al, Mn, Fe, Co, Ni, and Cu) in the groundwater in summer were approximately 20-fold higher than those in winter, with good correlation to each other. Overall, the concentrations of most of the trace elements in the groundwater were 3- to 70-fold higher than those in the seawater of this Bay. Simple budget calculations showed that large fluxes of submarine groundwater discharge (SGD)-driven trace elements were responsible for the unusually enhanced concentrations of trace elements (particularly for Al, Fe and Co) in the summer seawater. The results imply that the temporal changes in SGD-driven trace element fluxes are large and may contribute considerably to the budget of trace elements in the coastal ocean, particularly off a highly permeable volcanic island. 相似文献
926.
Flood risk assessment using regional regression analysis 总被引:2,自引:0,他引:2
This study aimed to create a flood risk map for ungauged regions, which have limited flood damage data and other relevant data. The fact that there is a shortage of data that are critical for the establishment of a flood assessment and mitigation plan is not surprising even in developed countries like South Korea. To address this problem, the regional regression concept in statistical hydrology was introduced to the flood risk assessment field in this study, and it was framed with a series of two regression functions: flood damage and regional coefficients. As the second regression function utilizes the local socioeconomic variables, the resulting flood risk map can reflect the spatial characteristics well. The proposed methodology was applied to create flood risk maps for the three metropolitan areas in South Korea. The comparison of the proposed methodology with the existing methods revealed that only the proposed methodology can produce a statistically meaningful flood risk map based on a recent major flood in 2001. 相似文献
927.
Lee Seon-Sik Ahn Hyung-Jin Hwang In-Uk Kim Eun Han Kyung-Nam 《Ocean Science Journal》2021,56(4):406-412
Ocean Science Journal - Carcinogenic disinfection by-products (DBPs) are formed as the result of the chlorination of power plant water cooling systems for biofouling purposes. Effects of cooling... 相似文献
928.
Izvestiya, Atmospheric and Oceanic Physics - Long-term average values and anomalies of the duration of the period of positive temperatures and the total water-temperature value have been calculated... 相似文献
929.
T.V. Donskaya D.P. Gladkochub V.S. Fedorovsky A.M. Mazukabzov M. Cho W. Cheong J. Kim 《Russian Geology and Geophysics》2013,54(10):1205-1218
We present geological, structural, and geochemical data on synmetamorphic granitoids from the Tutai and South Ol’khon plutons of the Ol’khon terrane (Central Asian Fold Belt) with an estimation of the U–Pb zircon age of the Tutai granites. The structural and petrological data suggest the synfolding and synmetamorphic origin of the granitoids. The U–Pb zircon age of the Tutai granites (488.6 ± 8.0 Ma) almost coincides with the previously estimated age of quartz syenites from the South Ol’khon pluton (495 ± 6 Ma). The plutons occupy the same position in the regional structure. The granitoids underwent final deformations and metamorphism at 464 ± 11 Ma. The Tutai pluton consists of moderately potassic granites, whereas the South Ol’khon pluton is made up of quartz syenites and granites. The geochemical characteristics of the granites from both plutons (low Y and Yb contents, fractionated REE patterns) indicate their formation under conditions of garnet crystallization in deep crustal restite. The higher Y and Yb contents of the South Ol’khon quartz syenites as compared with those of the granites suggest the lack of equilibrium between the quartz syenite magmas and garnet parageneses during their formation or evolution. The Tutai and South Ol’khon granites were derived from quartz-feldspar crustal rocks, whereas the South Ol’khon quartz syenites might have originated from a mixed (crust-mantle) source. It is presumed that the granitoids formed within accretion-thickened crust. Early accretion, which has been first identified in the region, affected not only the Pribrezhnaya zone (the zone of the Tutai and South Ol’khon plutons) but also the entire Anga–Satyurty megazone of the Ol’khon terrane. The accretion ended with the convergence and oblique collision of the Ol’khon terrane and Siberian continent, when strike-slip tectonics became ubiquitous. 相似文献