Tectonic Activities and Evolution of the Red River Delta (North Viet Nam) in the Holocene     

Phach  P. V.  Lai  V. C.  Shakirov  R. B.  Le  D. A.  Tung  D. X. 《Geotectonics》2020,54(1):113-129

Geotectonics - The Red River delta with an area of about 12 620 km2 is one of the largest deltas of Viet Nam and it also is one of the remarkable deltas of Asia. The delta was formed during...  相似文献   

Lacustrine sedimentological and geochemical records for the last 170 years of climate and environmental changes in southeastern China          下载免费PDF全文

Kandasamy Selvaraj  Bao Zhi Lin  Jiann‐Yuh Lou  Wei Lan Xia  Xiang Tong Huang  Chen‐Tung A. Chen 《Boreas: An International Journal of Quaternary Research》2016,45(1):165-179

Reconstruction of modern climate and environmental changes in east Asia using inland natural climate archives can provide valuable insights on decadal–multidecadal climate and environmental patterns that are probably related to both natural and anthropogenic forcing. Here we investigated an 89‐cm‐long sediment core (TH1) from Tian Lake, southeastern China, for sedimentological, physical and geochemical parameters in order to understand climate and environmental changes for the latest two centuries. ¹³⁷Cs‐ and ²¹⁰Pb‐based age models show that the fine sand–coarse silt‐dominated core contains ~170 years (c. AD 1842–2011) of continuous sedimentation. Sediments with fine sands, low MS values, high water content, high TOC content and a high C:N ratio from c. AD 1842 to 1897 suggest intense hydrological conditions and strong runoff in the catchment, probably because of a humid climate. From AD 1897 to 1990, sediments with very fine sand and coarse silt, high MS values, low water content and unchanged TOC and C:N ratios indicate normal hydrological conditions and in‐lake algae‐derived organic matter. During this interval, the chemical weathering indicators show stronger weathering conditions compared with sediments deposited during AD 1842–1897, supporting the dominance of weathered surface soil input in the earlier interval and physical erosion dominance in the later period, respectively. Since AD 1990, the continuous decrease of geochemical proxies suggests human‐interacted Earth surface processes in the catchment of Tian Lake. A PCA revealed four dominant geochemical controlling factors – detrital input, trophic status, grain size and early diagenesis –, accounting for 26, 20, 18 and 16% of total variance, respectively. This study for the first time provides lacustrine geochemical evidence for the most recent two centuries of climate and environmental changes in coastal southeastern China, a region that is currently undergoing an inversion of critical zone, i.e. an overturning of its soil profile, owing to swift modernization.  相似文献   

Reply to comment on ‘C.‐P. Tung,N.‐M. Hong,C.‐H. Chen,and Y.‐C. Tan. 2004. Regional daily baseflow prediction. Hydrological Processes 18: 2147–2164’     

Nien‐ming Hong  Chu‐hui Chen  Ching‐pin Tung  Yi‐chi Tan 《水文研究》2008,22(6):887-889

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Modelling climate‐change impacts on stream temperature of Formosan landlocked salmon habitat     

Ching‐Pin Tung  Tsung‐Yu Lee  Yi‐Chen Yang 《水文研究》2006,20(7):1629-1649

A physics‐based model is provided for predicting the impact of climate change on stream temperature and, in turn, on Formosan landlocked salmon (Oncorhynchus masou formosanus) habitat. Because upstream watersheds on Taiwan Island are surrounded with high and steep mountains, the influence of mountain shading on solar radiation and longwave radiation is taken into account by using a digital elevation model. Projections using CGCM2 and HADCM3 models and CCCM and GISS models provided information on future climatic conditions. The results indicate that annual average stream temperatures may rise by 0·5 °C (HADCM3 short term) to 2·9 °C (CGCM2 long term) due to climate change. The simulation results also indicate that the average suitable habitat for the Formosan landlocked salmon may decline by 333 m (HADCM3 short term) to 1633 m (CGCM2 long term) and 166 m (HADCM3 short term) to 1833 m (CGCM2 long term) depending on which thermal criterion (17 °C and 18 °C respectively) is applied. The results of this study draw attention to the tasks of Formosan landlocked salmon conservation agencies, not only with regard to restoration plans of the local environment, but also to the mitigation strategies to global climate change that are necessary and require further research. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Morpho‐Physiological Growth and Yield Responses of Two Contrasting Maize Cultivars to Cadmium Exposure          下载免费PDF全文

Shakeel Ahmad Anjum  Mohsin Tanveer  Saddam Hussain  Ehsan ullah  Longchang Wang  Imran Khan  Rana Abdul Samad  Shahbaz Atta Tung  Madiha Anam  Babar Shahzad 《洁净——土壤、空气、水》2016,44(1):29-36

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Incorporating daily rainfalls to derive rainfall DDF relationships at ungauged sites in Hong Kong and quantifying their uncertainty     

Peishi Jiang  Yeou-Koung Tung 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(1):45-62

Rainfall depth-duration-frequency (DDF) relationships are essential inputs for the design and management of various hydrosystem infrastructures (e.g., urban drainages, dams, dykes, etc.). In many cases, rainfall DDF relationships are required at a location where there is no gauge. However, due to the presence of intrinsic randomness of the precipitation process, limited rainfall record, and spatial interpolation, the derived DDF relationships at ungauged sites are subject to uncertainty. This is especially true in Hong Kong with regard to record length. To enhance the utilization of available rainfall data, a daily precipitation-based DDF generation framework for conventional rain gauges in Hong Kong has been developed by the authors utilizing a scaling model. In this article, the methodological framework is extended to derive rainfall DDF relationships at ungauged sites. Owing to the nonlinearity and complexity of the modeling process, exact statistical features of derived DDF relationships are difficult to obtain. In this study, Harr’s probabilistic point estimation method, known for its computational simplicity and accuracy, is applied to quantify the uncertainty features of rainfall DDF relationships derived for ungauged sites in Hong Kong. For illustration, four locations in different geographical locations in Hong Kong are considered. The results show that the uncertainty associated with the estimated statistical moments of annual maximum daily rainfall is significant in contributing to the overall uncertainty of derived rainfall DDF relationships.  相似文献   

Reliability analysis of hydraulic structures considering unit hydrograph uncertainty   总被引：1，自引：0，他引：1  

B. Zhao  Y. -K. Tung  K. -C. Yeh  J. -C. Yang 《Stochastic Hydrology and Hydraulics》1997,11(1):33-50

Unit hydrographs (UHs), along with design rainfalls, are frequently used to determine the discharge hydrograph for design and evaluation of hydraulic structures. Due to the presence of various uncertainties in its derivation, the resulting UH is inevitably subject to uncertainty. Consequently, the performance of hydraulic structures under the design storm condition is uncertain. This paper integrates the linearly constrained Monte-Carlo simulation with the UH theory and routing techniques to evaluate the reliability of hydraulic structures. The linear constraint is considered because the water volume of each generated design direct runoff hydrograph should be equal to that of the design effective rainfall hyetograph or the water volume of each generated UH must be equal to one inch (or cm) over the watershed. For illustration, the proposed methodology is applied to evaluate the overtopping risk of a hypothetical flood detention reservoir downstream of Tong-Tou watershed in Taiwan.  相似文献   

Prediction of the spatial distribution of the modified mercalli intensity using neural networks     

Albert T. Y. Tung  Felix S. Wong  Weimin Dong 《地震工程与结构动力学》1994,23(1):49-62

This paper presents the development of an adaptive, non-parametric forecast model for the direct prediction of the spatial distribution of the Modified Mercalli Intensity (MMI) corresponding to an earthquake scenario. The model is based on recent advances in neural networks computation, and is constructed through supervised learning using historical earthquake and regional geological data as training sets. A MMI forecast model for moderate earthquakes with magnitudes between 6 and 7 was developed based on data from the Loma Prieta, Coalinga and Morgan Hill earthquakes. For these data sets, the neural networks forecast model is shown to have excellent data synthesis capability; multiple sets of data can be encapsulated by a relatively simple network architecture. Limited comparison of forecasts made by the neural networks model and conventional models demonstrates that improved accuracy can be achieved. Implementation and operational advantages of the neural networks approach such as general input features, minimum preconceived knowledge of the data sets, the ability to learn and to adapt incrementally and the autonomous and automatic synthesis of the structure underlying the data sets, have been illustrated.  相似文献   

Extreme value distribution of earthquake magnitude     

C.C. Tung 《Physics of the Earth and Planetary Interiors》1983,32(4):325-330

Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent.  相似文献   

Identification and stochastic generation of representative rainfall temporal patterns in Hong Kong territory     

Shiang-Jen Wu  Jinn-Chuang Yang  Yeou-Koung Tung 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,20(3):171-183

In hydrosystem engineering design and analysis, temporal pattern for rainfall events of interest is often required. In this paper, statistical cluster analysis of dimensionless rainfall pattern is applied to identify representative temporal rainfall patterns typically occurred in Hong Kong Territory. For purpose of selecting an appropriate rainfall pattern in engineering applications, factors affecting the occurrence of different rainfall patterns are examined by statistical contingency tables analysis through which the inter-dependence of the occurrence frequency of rainfall patterns with respect to geographical location, rainfall duration and depth, and seasonality is investigated. Furthermore, due to inherent variability of rainfall mass curves or hyetographs within each classified rainfall pattern, a practical procedure to probabilistically generate plausible rainfall patterns is described. The procedure preserves the inherent stochastic features of random dimensionless rainfall hyetograph ordinates, which in general are correlated non-normal multivariate compositional variables.  相似文献