Stepwise inversion of a groundwater flow model with multi-scale observation data   总被引：1，自引：0，他引：1  

Zhenxue Dai  Elizabeth Keating  Carl Gable  Daniel Levitt  Jeff Heikoop  Ardyth Simmons 《Hydrogeology Journal》2010,18(3):607-624

Based on the regional hydrogeology and the stratigraphy beneath the Los Alamos National Laboratory (LANL) site, New Mexico (USA), a site-scale groundwater model has been built with more than 20 stratified hydrofacies. A stepwise inverse method was developed to estimate permeabilities for these hydrofacies by coupling observation data from different sources and at various spatial scales including single-well test, multiple-well pumping test and regional aquifer monitoring data. Statistical analyses of outcrop permeability measurements and single-well test results were used to define the prior distributions of the parameters. These distributions were used to define the parameter initial values and the lower and upper bounds for inverse modeling. A number of inverse modeling steps were performed including the use of drawdown data from the pump tests at two wells (PM-2 and PM-4) separately, and a joint inversion coupling PM-2 and PM-4 pump test data and head data from regional aquifer monitoring. Parameter sensitivity coefficients for different data sets were computed to analyze if the model parameters can be estimated accurately with the data provided at different steps. The joint inversion offers a reasonable fit to all data sets. The uncertainty of estimated parameters for the hydrofacies is addressed with the parameter confidence intervals.  相似文献   

从地震信息看阿尔金断裂带构造和塔里木盆地花彩弧断裂体系   总被引：1，自引：0，他引：1  

杨建  戴福贵  吴红华  杨克绳 《海相油气地质》2010,15(2):56-63

阿尔金断裂带由多条断裂组成,主要有阿尔金断裂、且末断裂、三危山断裂。其中阿尔金断裂为主断裂,它呈左旋走滑兼具逆冲性质,中生代—古近纪为左旋走滑,新近纪由东南向西北逆冲推覆。且末断裂和三危山断裂均具左旋走滑性质。且末断裂受统一的阿尔金断裂带左旋应力场控制,但又叠加了塔里木台盆区向南挤压的应力场,从而具有双重属性。塔里木盆地的断裂总体上组成古生界塔北花彩弧断裂束和塔南花彩弧断裂束,展布成全盆地的菱形断裂系统,且末断裂构成其东南边界。在该菱形断裂系统的北弧顶和菱形内的中央轴部为背冲式的构造断裂带,显示挤压特征;在花彩弧两翼转弯处展布正花状构造样式,显示走滑特征。阿尔金断裂带及其两侧,主要在柴达木、塔里木两大盆地发现了大油气田,两者都是由断层控制油气的垂向运移与分布。柴达木盆地具有双重断—坳的特点,但油气田只分布在中—新生界构造层内;塔里木盆地,南北翘板式的构造运动是其形成复式油气区的最重要的地质构造条件。  相似文献   

Integrated water resource security evaluation of Beijing based on GRA and TOPSIS   总被引：2，自引：0，他引：2  

Jing Dai  Jing Qi  Jingjing Chi  Shaoqing Chen  Jin Yang  Liping Ju  Bin Chen 《Frontiers of Earth Science》2010,4(3):357-362

Security evaluation has become a hot topic in the research field of water resource management. In this paper, we established a novel water resource security indicator system based on the Pressure-Status-Response (PSR) framework using gray relation analysis (GRA) and technique for order preference by similarity to ideal solution (TOPSIS). A case study of Beijing from 1996 to 2007 was conducted to verify the evaluation system. Results showed that the gray relative closeness degrees of water resource security to the positive ideal solution were low, with the least one of 0.360 in 1999 and the largest one of 0.527 in 2007, implying that Beijing was facing severer challenges with water resources during the concerned time. Also, the analysis of water resource security indicated that the pressure of water resource was constantly increasing. Finally, factor analysis was employed to calculate the gray relation degrees of evaluating indices with the ideal solutions so as to reveal the relativity of water resource security of Beijing, which may contribute to a better understanding of the urban water resource management and regulation.  相似文献   

川南煤田象顶井田瓦斯赋存特征及影响因素     

戴敬儒  吴永贵 《中国煤炭地质》2010,(12):18-23

根据象顶井田大量瓦斯实测资料分析,区内瓦斯含量高分带不明显,沼气带在埋深100m以下,瓦斯含量有随埋深增加而增大的趋势,但相关性不显著,地质构造及水文条件是影响区内瓦斯分布的主要因素。井田内先期发育的压性层间滑动断层(f701)及其派生断层纵贯全区,导致构造煤发育,瓦斯含量高;中部及西南部的F39、F418、F428、F405张性正断层切割了先期的压性断层,断层破碎带及裂隙为瓦斯逸散提供了通道,同时断层使上盘煤层与下盘岩溶发育的茅口灰岩直接接触,加速了瓦斯的逸散,致使该区域内煤层瓦斯含量降低,形成了井田北东部瓦斯含量高、中部及南西部含量相对较低的格局。根据煤体结构、构造分布、煤层特征,预测区内C19煤层易发生突出区域位于井田北东部。  相似文献   

Potentials of phototrophic bacteria in treating pharmaceutical wastewater   总被引：7，自引：6，他引：1  

E. I. Madukasi  X. Dai  C. He  J. Zhou 《International Journal of Environmental Science and Technology》2010,7(1):165-174

A suspended growth photobioreactor was utilized to treat pharmaceutical wastewater by a wild strain purple non-sulfur photosynthetic bacterium isolated from the soil. The strain was named Z08 and identified as Rhodobacter-sphaeroides by 16SrDN. The photobioreactor was illuminated externally with two (40 W) fluorescent compact light sources on both sides. Its operation pH and temperature were between 6.8–7.0 and 20–30 °C, respectively. Optimum growth of the isolate was obtained after enrichment of the pharmaceutical wastewater with 0.5 % ammonium sulfate and 0.1 % yeast extract under microaerobic optimum light (6000 lx) condition at 5d retention. Using these optimum conditions, the maximum dry cell weight and chemical oxygen demand percentage removal were 880 mg/L and 80 %. Chemical analysis of the culture after treatment of the enriched and non-enriched wastewater showed the crude protein content of the biomass to be 54.6 % and 38.0 %, respectively. This study proved that photosynthetic bacteria could transform complex wastewater that contains recalcitrant organic compounds with a resultant recovery of useful products.  相似文献   

Bosumtwi impact structure,Ghana: Geochemistry of impactites and target rocks,and search for a meteoritic component     

Xiongxin Dai  Daniel Boamah  Christian Koeberl  Wolf Uwe Reimold  Gordon Irvine  Iain McDonald 《Meteoritics & planetary science》2005,40(9-10):1493-1511

Abstract— Major and trace element data, including platinum group element abundances, of representative impactites and target rocks from the crater rim and environs of the Bosumtwi impact structure, Ghana, have been investigated for the possible presence of a meteoritic component in impact‐related rocks. A comparison of chemical data for Bosumtwi target rocks and impactites with those for Ivory Coast tektites and microtektites supports the interpretation that the Bosumtwi structure and Ivory Coast tektites formed during the same impact event. High siderophile element contents (compared to average upper crustal abundances) were determined for target rocks as well as for impactites. Chondrite‐normalized (and iron meteorite‐normalized) abundances for target rocks and impactites are similar. They do not, however, allow the unambiguous detection of the presence, or identification of the type, of a meteoritic component in the impactites. The indigenous siderophile element contents are high and possibly related to regional gold mineralization, although mineralized samples from the general region show somewhat different platinum‐group element abundance patterns compared to the rocks at Bosumtwi. The present data underline the necessity of extensive target rock analyses at Bosumtwi, and at impact structures in general, before making any conclusions regarding the presence of a meteoritic component in impactites.  相似文献   

Artificial neural network models for estimating regional reference evapotranspiration based on climate factors     

Xiaoqin Dai  Haibin Shi  Yunsheng Li  Zhu Ouyang  Zailin Huo 《水文研究》2009,23(3):442-450

Evapotranspiration (ET) is one of the basic components of the hydrologic cycle and is essential for estimating irrigation water requirements. In this study, an artificial neural network (ANN) model for reference evapotranspiration (ET₀) calculation was investigated. ANNs were trained and tested for arid (west), semi‐arid (middle) and sub‐humid (east) areas of the Inner Mongolia district of China. Three or four climate factors, i.e. air temperature (T), relative humidity (RH), wind speed (U) and duration of sunshine (N) from 135 meteorological stations distributed throughout the study area, were used as the inputs of the ANNs. A comparison was conducted between the estimates provided by the ANNs and by multilinear regression (MLR). The results showed that ANNs using the climatic data successfully estimated ET₀ and the ANNs simulated ET₀ better than the MLRs. The ANNs with four inputs were more accurate than those with three inputs. The errors of the ANNs with four inputs were lower (with RMSE of 0·130 mm d^?1, RE of 2·7% and R² of 0·986) in the semi‐arid area than in the other two areas, but the errors of the ANNs with three inputs were lower in the sub‐humid area (with RMSE of 0·21 mm d^?1, RE of 5·2% and R² of 0·961. For the different seasons, the results indicated that the highest errors occurred in September and the lowest in April for the ANNs with four inputs. Similarly, the errors were higher in September for the ANNs with three inputs. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Coastal deformation between the Versilia and the Garigliano plains (Italy) since the last interglacial stage     

Marco F. Nisi  Fabrizio Antonioli  Giuseppe Dai Pra  Gabriele Leoni  Sergio Silenzi 《第四纪科学杂志》2003,18(8):709-721

The opening of the north‐central Tyrrhenian Sea is the result of the Cretaceous–Paleogene alpine collision, which triggered a series of regional uplift, subsidence and transcurrent tectonic mechanisms along the coastal Tyrrhenian sectors of peninsular Italy. These tectonic processes, in conjunction with the effects of glacio‐ and hydro‐isostasy during the Quaternary, produced substantial crustal responses that, in some cases, reached metres in extent. In the study of coastal neotectonics, geomorphological markers of the last interglacial maximum, corresponding to marine isotope stage 5.5, are generally used to quantify the magnitude of the vertical crustal displacements that have occurred since 125 kyr. Through altimetrical, palaeoenvironmental and chronological reinterpretation of the most significant works published since 1913, combined with an additional set of data reported here, a detailed reconstruction of the shoreline displacements evident along 500 km of coast between northern Tuscany and southern Latium is presented. The reconstruction was carried out by quantifying the vertical movement since the last interglacial period and by identifying the tectonic behaviour of different coastal sectors. This has been done by carefully choosing the eustatic marker, among those available at each study site, in order to minimize the margin of error associated with the measurements. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

The Influences of Mg^2 ,Ca^2 ,and Mg^2 /Ca^2 Ratio in Mixed Seawater on the Emergence Rate of Penaeus Japonicus Postlarva     

臧维玲  徐桂荣等 《中国海洋湖沼学报》2003,21(1):78-85

This paper reports the approprite ranges of Mg^2 ,Ca^2 and their ratio Mg^2 /Ca^2 in mixed seawater for rearing of Penaeus japonicus larvae,The ranges for the above three indices are 1150-1450mg/L,360-440mg/L and 2.8-3.4,respectively,the proper salinity range of mixed seawater is 22.1-33.9 obtained by mixing estuarine water and concentrated seawater.  相似文献   

Properties of BL Lac Objects with Redshift < 0.2     

BenZhong Dai  GuangZhong Xie  ZeJun Jiang 《中国天文和天体物理学报》2002,2(1)

We present a large sample which includes 82 BL Lac objects with redshifts below 0.2 from recent literature. We find strong correlations in both flux and luminosity between the radio (5 GHz) and optical bands (5500 A). The correlations in other bands are very weak. Five TeV BL Lacs and two suspect sources are found to have similar properties as high-frequency-peaked BL Lacs (HBLs). Our results suggest that both the radio and optical emissions are from the same radiation mech anism in the SSC model. The TeV BL Lac candidates should be HBLs or HBL-like objects with small redshifts.  相似文献