Rapid changes of sediment dynamic processes in Yalu River Estuary under anthropogenic impacts   总被引：2，自引：0，他引：2  

Jian-hua GAO  Jun LI  Harry WANG  Fen-long BAI  Yan CHENG  Ya-ping WANG 《国际泥沙研究》2012,27(1):37-49

The response of the Yalu River Estuary to human activities was investigated.Changes of sediment dynamics during the past 10 years were explored through hydrodynamic calculation,as well as heavy mineral...  相似文献   

Simulations of spatial variability in particle‐size emissions during wind erosion events     

Harry J. Butler  Grant H. McTainsh  William L. Hogarth 《地球表面变化过程与地形》2012,37(13):1362-1375

This study simulates how spatial variations in particle‐size emissions from a playa affect bulk and size‐resolved dust concentration profiles during two contrasting wind erosion events (a small local and a large regional event) in the Channel Country, Lake Eyre Basin, Australia. The regional event had higher dust concentration as a result of stronger frontal winds and higher erodibility across the playa. For each event, two emission scenarios are simulated to determine if measured size‐resolved dust concentration profiles can be explained by spatial variability in source area emissions. The first scenario assumes that particle‐size emissions from source areas occur at a uniform rate, while the second scenario assumes that particle‐size emissions vary between and within source areas. The uniform emission scenario, reproduced measured bulk dust concentration profiles (R² = 0·93 regional and R² = 0·81 local), however simulated size‐resolved dust concentration profiles had poor statistical fits to measured size‐resolved profiles for each size class (the highest were R² = 0·5 regional and R² = 0·3 local). For the differential particle‐size emission scenario, the fit to the measured bulk dust concentration profiles is improved (R² = 0·97 regional and R² = 0·83 local). However, the fit to the size‐resolved profiles improved dramatically, with the lowest being R² = 0·89 (regional) and R² = 0·80 (local). Particle‐size emission models should therefore be tested against both bulk and size‐resolved dust concentration profiles, since if only bulk dust concentration profiles are used model performance may be over‐stated. As the source areas in the first 90 m upwind of the tower were similar for both events, the percentage contributions of each particle‐size class to total emissions can be compared. The contribution of each particle‐size class was similar even though the wind speed, turbulence and dust concentrations were significantly different; suggesting that the contribution of each particle‐size to the total emitted dusts is not related to wind speed and turbulence. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Three-dimensional geostatistical inversion of flowmeter and pumping test data   总被引：1，自引：0，他引：1  

Li W  Englert A  Cirpka OA  Vereecken H 《Ground water》2008,46(2):193-201

We jointly invert field data of flowmeter and multiple pumping tests in fully screened wells to estimate hydraulic conductivity using a geostatistical method. We use the steady-state drawdowns of pumping tests and the discharge profiles of flowmeter tests as our data in the inference. The discharge profiles need not be converted to absolute hydraulic conductivities. Consequently, we do not need measurements of depth-averaged hydraulic conductivity at well locations. The flowmeter profiles contain information about relative vertical distributions of hydraulic conductivity, while drawdown measurements of pumping tests provide information about horizontal fluctuation of the depth-averaged hydraulic conductivity. We apply the method to data obtained at the Krauthausen test site of the Forschungszentrum Jülich, Germany. The resulting estimate of our joint three-dimensional (3D) geostatistical inversion shows an improved 3D structure in comparison to the inversion of pumping test data only.  相似文献   

Modelling the water balance of a mesoscale catchment basin using remotely sensed land cover data     

Carsten Montzka  Morton Canty  Ralf Kunkel  Gunter Menz  Harry Vereecken  Frank Wendland 《Journal of Hydrology》2008,353(3-4):322-334

Hydrological modelling of mesoscale catchments is often adversely affected by a lack of adequate information about specific site conditions. In particular, digital land cover data are available from data sets which were acquired on a European or a national scale. These data sets do not only exhibit a restricted spatial resolution but also a differentiation of crops and impervious areas which is not appropriate to the needs of mesoscale hydrological models. In this paper, the impact of remote sensing data on the reliability of a water balance model is investigated and compared to model results determined on the basis of CORINE (Coordination of Information on the Environment) Land Cover as a reference. The aim is to quantify the improved model performance achieved by an enhanced land cover representation and corresponding model modifications. Making use of medium resolution satellite imagery from SPOT, LANDSAT ETM+ and ASTER, detailed information on land cover, especially agricultural crops and impervious surfaces, was extracted over a 5-year period (2000–2004). Crop-specific evapotranspiration coefficients were derived by using remote sensing data to replace grass reference evapotranspiration necessitated by the use of CORINE land cover for rural areas. For regions classified as settlement or industrial areas, degrees of imperviousness were derived. The data were incorporated into the hydrological model GROWA (large-scale water balance model), which uses an empirical approach combining distributed meteorological data with distributed site parameters to calculate the annual runoff components. Using satellite imagery in combination with runoff data from gauging stations for the years 2000–2004, the actual evapotranspiration calculation in GROWA was methodologically extended by including empirical crop coefficients for actual evapotranspiration calculations. While GROWA originally treated agricultural areas as homogeneous, now a consideration and differentiation of the main crops is possible. The accuracy was determined by runoff measurements from gauging stations. Differences in water balances resulting from the use of remote sensing data as opposed to CORINE were analysed in this study using a representative subcatchment. Resulting Nash–Sutcliff model efficiencies improved from 0.372 to 0.775 and indicate that the enhanced model can produce thematically more accurate and spatially more detailed local water balances. However, the proposed model enhancements by satellite imagery have not exhausted the full potential of water balance modelling, for which a higher temporal resolution is required.  相似文献   

The influence of precipitate formation on the chemical oxidation of TCE DNAPL with potassium permanganate     

Michael R. West  Gavin P. Grant  Jason I. Gerhard  Bernard H. Kueper 《Advances in water resources》2008

A three-dimensional two-phase flow model is coupled to a non-linear reactive transport model to study the efficacy of potassium permanganate treatment on dense, non-aqueous phase liquid (DNAPL) source removal in porous media. A linear relationship between the soil permeability (k) and concentration of manganese dioxide precipitate ([MnO_2(s)]), k = k_o + S_rind [MnO_2(s)], is utilized to simulate nodal permeability reductions due to precipitate formation. Using published experimental column studies, an S_rind = −5.5 × 10⁻¹⁶ m² L/mg was determined for trichloroethylene (TCE) DNAPL. This S_rind was then applied to treatment simulations on three-dimensional TCE DNAPL source zones comprising either DNAPL at residual saturations, or DNAPL at pooled saturations.  相似文献   

Autobiography of Harry E. LeGrand     

by Harry E. LeGrand 《Ground water》2009,47(6):870-874

  相似文献   

准噶尔盆地腹部超压顶面附近深层砂岩碳酸盐胶结作用和次生溶蚀孔隙形成机理   总被引：2，自引：1，他引：1  

何生  杨智  何治亮  武恒志  王芙蓉  孟闲龙 《地球科学》2009,34(5):759-768

准噶尔盆地腹部深层超压顶面附近(现今埋深4400~6200m, 温度105~145℃) 砂岩中广泛出现的碳酸盐胶结作用和次生溶蚀孔隙与超压流体活动关系密切.由于超压封闭和释放引起其顶面附近砂岩中的孔隙压力和水化学环境的周期性变化可导致碳酸盐沉淀和易溶矿物溶解过程交替出现.根据腹部地区超压顶面附近深埋砂岩成岩作用、碳酸盐胶结物含量、储集物性、碳酸盐胶结物碳、氧同位素和烃源岩热演化模拟等资料的综合研究表明: 含铁碳酸盐胶结物是主要的胶结成分, 长石类成分的次生溶蚀孔隙是主要的储集空间类型, 纵向上深层砂岩碳酸盐胶结物出现15%~30%含量的地层厚度范围约在邻近超压顶面之下100m至之上大于450m, 碳酸盐胶结物出现大于25%含量高值带分布在靠近超压顶面向上的250~300m的地层厚度范围, 超压顶面附近砂岩中碳酸盐胶结物含量高值的深度范围也是次生溶蚀孔隙(孔隙度10%~20%) 发育带的范围; 因晚白垩世以来深部侏罗纪煤系有机质生烃增压作用, 导致在超压顶面附近砂岩晚成岩作用阶段深部富含碳酸盐的超压流体频繁活动, 所形成的碳酸盐胶结物受到了明显的与深部生烃增压有关的超压热流体和有机脱羧作用的影响; 超压流体多次通过超压顶面排放, 使得超压顶面附近砂岩遭受了多期酸性流体溶蚀作用过程, 形成了次生溶蚀孔隙发育带.   相似文献   

Synergy between Virtual Local Air Pollutants and Greenhouse Gases Emissions Embodied in China’s International Trade     

CHEN Yiying  LEE Harry. F.  WANG Ke  PEI Qing  ZOU Ji 《资源与生态学报(英文版)》2017,8(6):571-583

Increasing pressure from the international community to reduce carbon emissions, coupled with the need to reduce domestic air pollutants, is forcing China to deal with both sources of emissions. Air pollutants and greenhouse gases are closely linked via their common source, fossil fuels. As a result of globalization, large portions of these emissions are associated with trade. This study uses data from the World Input-Output Database (WIOD), including 27 EU countries and 13 major countries, covering the period from 2000 to 2009, and applies MRIO (Multiregional input-output) to estimate emissions embodied in China’s international trade. We focus on the synergy between LAPs (local air pollutants) and GHG consumption-based emissions, and the relationship between virtual LAPs and virtual GHGs associated with China’s international trade from 2000 to 2009. The results indicate that a strong synergistic relationship exists and that air pollutant control can serve as an endogenous mechanism to mitigating greenhouse gases. Thanks to domestic actions to control air pollutants, every ton reduction of LAP emissions related to export can save 27.1 tons of GHG emissions in 2005 over emissions efficiency levels, and can save 32.4 tons of GHG emissions in 2009 over 2005. Mitigation actions taken to reduce air pollutants could also reduce GHG emissions.  相似文献   

The WASP project in the era of robotic telescope networks     

D. J. Christian  D. L. Pollacco  I. Skillen  J. Irwin  W. I. Clarkson  A. Collier Cameron  N. Evans  A. Fitzsimmons  C. A. Haswell  C. Hellier  S. T. Hodgkin  K. Horne  S. R. Kane  F. P. Keenan  T. A. Lister  A. J. Norton  J. Osborne  R. Ryans  R. A. Street  R. G. West  P. J. Wheatley 《Astronomische Nachrichten》2006,327(8):800-802

We present the current status of the WASP project, a pair of wide angle photometric telescopes, individually called Super‐WASP. SuperWASP‐I is located in La Palma, and SuperWASP‐II at Sutherland in South Africa. SW‐I began operations in April 2004. SW‐II is expected to be operational in early 2006. Each SuperWASP instrument consists of up to 8 individual cameras using ultra‐wide field lenses backed by high‐quality passively cooled CCDs. Each camera covers 7.8 × 7.8 sq degrees of sky, for nearly 500 sq degrees of total sky coverage. One of the current aims of the WASP project is the search for extra‐solar planet transits with a focus on brighter stars in the magnitude range ∼8 to 13. Additionally, WASP will search for optical transients, track Near‐Earth Objects, and study many types of variable stars and extragalactic objects. The collaboration has developed a custom‐built reduction pipeline that achieves better than 1 percent photometric precision. We discuss future goals, which include: nightly on‐mountain reductions that could be used to automatically drive alerts via a small robotic telescope network, and possible roles of the WASP telescopes as providers in such a network. Additional technical details of the telescopes, data reduction, and consortium members and institutions can be found on the web site at: http://www.superwasp.org/. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Book review     

Harry M. Parker 《Mathematical Geology》1988,20(7):899-903

  相似文献