Characterization of complex fluvial systems using remote sensing of spatial and temporal water level variations in the Amazon,Congo, and Brahmaputra Rivers   总被引：1，自引：0，他引：1  

Hahn Chul Jung  James Hamski  Michael Durand  Doug Alsdorf  Faisal Hossain  Hyongki Lee  A. K. M. Azad Hossain  Khaled Hasan  Abu Saleh Khan  A.K.M. Zeaul Hoque 《地球表面变化过程与地形》2010,35(3):294-304

The Surface Water and Ocean Topography (SWOT) satellite mission will provide global, space‐based estimates of water elevation, its temporal change, and its spatial slope in fluvial environments, as well as across lakes, reservoirs, wetlands, and floodplains. This paper illustrates the utility of existing remote sensing measurements of water temporal changes and spatial slope to characterize two complex fluvial environments. First, repeat‐pass interferometric SAR measurements from the Japanese Earth Resources Satellite are used to compare and contrast floodplain processes in the Amazon and Congo River basins. Measurements of temporal water level changes over the two areas reveal clearly different hydraulic processes at work. The Amazon is highly interconnected by floodplain channels, resulting in complex flow patterns. In contrast, the Congo does not show similar floodplain channels and the flow patterns are not well defined and have diffuse boundaries. During inundation, the Amazon floodplain often shows sharp hydraulic changes across floodplain channels. The Congo, however, does not show similar sharp changes during either infilling or evacuation. Second, Shuttle Radar Topography Mission measurements of water elevation are used to derive water slope over the braided Brahmaputra river system. In combination with in situ bathymetry measurements, water elevation and slope allow one to calculate discharge estimates within 2.3% accuracy. These two studies illustrate the utility of satellite‐based measurements of water elevation for characterizing complex fluvial environments, and highlight the potential of SWOT measurements for fluvial hydrology. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Sampling transects for affordable, high-resolution plume characterization and monitoring     

Einarson MD  Mackay DM  Bennett PJ 《Ground water》2010,48(6):805-808

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News & Views     

Vicki Kretsinger Grabert  Dawn Samara Kaback  Beth L. Parker  Steven W. Chapman  John A. Cherry  Francis H. Chapelle  Michael A. Singletary  Murray D. Einarson  Doug M. Mackay  Peter J. Bennett 《Ground water》2010,48(6):799-808

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Forecasting skill of model averages   总被引：1，自引：1，他引：0  

C. L. Winter  Doug Nychka 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(5):633-638

Given a collection of science-based computational models that all estimate states of the same environmental system, we compare the forecast skill of the average of the collection to the skills of the individual members. We illustrate our results through an analysis of regional climate model data and give general criteria for the average to perform more or less skillfully than the most skillful individual model, the “best” model. The average will only be more skillful than the best model if the individual models in the collection produce very different forecasts; if the individual forecasts generally agree, the average will not be as skillful as the best model.  相似文献   

Geomechanical property estimation of unconventional reservoirs using seismic data and rock physics          下载免费PDF全文

Andrea Cortis  Jinsong Chen  Doug Sassen  Howard Rael 《Geophysical Prospecting》2015,63(5):1224-1245

An extension of a previously developed rock physics model is made that quantifies the relationship between the ductile fraction of a brittle/ductile binary mixture and the isotropic seismic reflection response. By making a weak scattering (Born) approximation and plane wave (eikonal) approximation, with a subsequent ordering according to the angles of incidence, singular value decomposition analyses are performed to understand the stack weightings, number of stacks, and the type of stacks that will optimally estimate two fundamental rock physics parameters – the ductile fraction and the compaction and/or diagenesis. It is concluded that the full PP stack, i.e., sum of all PP offset traces, and the “full” PS stack, i.e., linear weighted sum of PS offset traces, are the two optimal stacks needed to estimate the two rock physics parameters. They dominate over both the second‐order amplitude variation offset “gradient” stack, which is a quadratically weighted sum of PP offset traces that is effectively the far offset traces minus the near offset traces, and the higher order fourth order PP stack (even at large angles of incidence). Using this result and model‐based Bayesian inversion, the seismic detectability of the ductile fraction (shown by others to be the important rock property for the geomechanical response of unconventional reservoir fracking) is demonstrated on a model characteristic of the Marcellus shale play.  相似文献   

Communicating biophysical conditions across New Zealand's rivers using an interactive webtool     

Amy L. Whitehead  Doug J. Booker 《新西兰海洋与淡水研究杂志》2019,53(2):278-287

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AgCam传感器平场校正     

窦长勇  张晓东  Doug Olsen  贺明霞 《中国海洋大学学报(自然科学版)》2010,40(9)

平场校正对获得高质量的遥感图像起着非常关键的作用。针对利用商业相机开发的传感器需要进行平场校正的问题,提出对Agriculture Camera(AgCam)传感器的平场校正方法。应用AgCam的定标实验数据分别得到传感器CCD阵列的暗电流(Dark Current),渐晕效应(Vegnitting Effect)和光电响应(Quantum Efficiency)的校正系数。AgCam的定标实验数据和实际拍摄图像处理结果表明,该方法能够有效地对AgCam的平场效应进行校正。  相似文献   

Modelling discontinuity control on the development of Hell’s Mouth landslide     

He  Lingfeng  Coggan  John  Stead  Doug  Francioni  Mirko  Eyre  Matthew 《Landslides》2022,19(2):277-295

Landslides - This paper focuses on numerical modelling and back analysis of the Hell’s Mouth landslide to provide improved understanding of the evolution of a section of the north coast of...  相似文献   

Experimental study of the aragonite to calcite transition in aqueous solution     

Christina Perdikouri  Thorsten Geisler  Burkhard C. Schmidt 《Geochimica et cosmochimica acta》2011,75(20):6211-6224

The experimental replacement of aragonite by calcite was studied under hydrothermal conditions at temperatures between 160 and 200 °C using single inorganic aragonite crystals as a starting material. The initial saturation state and the total [Ca²⁺]:[CO₃²⁻] ratio of the experimental solutions was found to have a determining effect on the amount and abundance of calcite overgrowths as well as the extent of replacement observed within the crystals. The replacement process was accompanied by progressive formation of cracks and pores within the calcite, which led to extended fracturing of the initial aragonite. The overall shape and morphology of the parent aragonite crystal were preserved. The replaced regions were identified with scanning electron microscopy and Raman spectroscopy.Experiments using carbonate solutions prepared with water enriched in ¹⁸O (97%) were also performed in order to trace the course of this replacement process. The incorporation of the heavier oxygen isotope in the carbonate molecule within the calcite replacements was monitored with Raman spectroscopy. The heterogeneous distribution of ¹⁸O in the reaction products required a separate study of the kinetics of isotopic equilibration within the fluid to obtain a better understanding of the ¹⁸O distribution in the calcite replacement. An activation energy of 109 kJ/mol was calculated for the exchange of oxygen isotopes between [C¹⁶O₃²⁻]_aq and [H₂¹⁸O] and the time for oxygen isotope exchange in the fluid at 200 °C was estimated at ∼0.9 s. Given the exchange rate, analyses of the run products imply that the oxygen isotope composition in the calcite product is partly inherited from the oxygen isotope composition of the aragonite parent during the replacement process and is dependent on access of the fluid to the reaction interface rather than equilibration time. The aragonite to calcite fluid-mediated transformation is described by a coupled dissolution-reprecipitation mechanism, where aragonite dissolution is coupled to the precipitation of calcite at an inwardly moving reaction interface.  相似文献   

Young star clusters immersed in intermediate-age fields in the Large Magellanic Cloud bar     

Andrés E. Piatti  Doug Geisler  Eduardo Bica  Juan J. Clariá 《Monthly notices of the Royal Astronomical Society》2003,343(3):851-862

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