Short‐term Effects of Gray Wastewater on a Mediterranean Sandy Soil          下载免费PDF全文

Ali Mekki  Firas Fki  Mariem Kchaou  Sami Sayadi 《洁净——土壤、空气、水》2015,43(5):754-760

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Noise Reduction in Radon Monitoring Data Using Kalman Filter and Application of Results in Earthquake Precursory Process Research     

Mojtaba Namvaran  Ali Negarestani 《Acta Geophysica》2015,63(2):329-351

Monitoring the concentration of radon gas is an established method for geophysical analyses and research, particularly in earthquake studies. A continuous radon monitoring station was implemented in Jooshan hotspring, Kerman province, south east Iran. The location was carefully chosen as a widely reported earthquake-prone zone. A common issue during monitoring of radon gas concentration is the possibility of noise disturbance by different environmental and instrumental parameters. A systematic mathematical analysis aiming at reducing such noises from data is reported here; for the first time, the Kalman filter (KF) has been used for radon gas concentration monitoring. The filtering is incorporated based on several seismic parameters of the area under study. A novel anomaly defined as “radon concentration spike crossing” is also introduced and successfully used in the study. Furthermore, for the first time, a mathematical pattern of a relationship between the radius of potential precursory phenomena and the distance between epicenter and the monitoring station is reported and statistically analyzed.  相似文献   

Recent Sea Level and Sea Surface Temperature Trends Along the Bangladesh Coast in Relation to the Frequency of Intense Cyclones     

Tariq Masood Ali Khan  O. P. Singh  Md. Sazedur Rahman 《Marine Geodesy》2013,36(2):103-116

The French Transportable Laser Ranging System (FTLRS) was deployed in the calibration site of satellite radar altimeters in Corsica over the 2002 and 2005 campaigns. The paper describes the different steps of SLR data processing. The average arcs RMS obtained are about 1–2 cm for Lageos-1&;-2, Starlette and Stella satellites; it is shown that the best results of satellite orbits determination and geocentric positioning are obtained with Eigen-Grace03s gravity model. The difference of FTLRS absolute 3D positioning, between 2002 and 2005, of about 7.7 mm (i.e., 2.6 mm/yr) is less than residual errors of ITRF2005 velocities (of about 4.3 mm/yr).  相似文献   

Assessing the Performance of Independent Component Analysis in Remote Sensing Data Processing     

Raoof Gholami  Ali Moradzadeh  Mahyar Yousefi 《Journal of the Indian Society of Remote Sensing》2012,40(4):577-588

Independent component analysis (ICA) is a novel method to be considered as a powerful type of analysis in the process of source signal separation. Based on the capabilities of this particular analysis, there will be a hypothesis of applying ICA in the image processing of remote sensing data. This paper aims to introduce the ability of ICA in contrasting and highlighting some area with potential of mineralization. Considering and applying ICA transformation on the ETM⁺ image of southern Masule, Iran has resulted in finding some favorable points for further investigation. Moreover, sampling program on the indicated area has led to identify some huge, unexpected lithology and dikes. ICA analysis is a robust method even in remote sensing data processing with the high speed and capabilities in separating source signals from noise.  相似文献   

内蒙古拐子湖地区风沙运动若干参数计算   总被引：1，自引：0，他引：1       下载免费PDF全文

何清  胡文峰  杨兴华  艾力·买买提明  赵聪敏 《干旱区地理》2012,35(2):187-192

 利用内蒙古拐子湖地区风沙观测场2011年3～5月的沙尘暴强化观测资料,分析计算了巴丹吉林沙漠北缘平坦沙地的地表粗糙度、临界摩擦速度、临界起沙风速等风沙运动关键参数。初步结论如下：观测期间地表粗糙度的变化范围为1.0×10-7～ 9.0×10-1cm,平均粗糙度为0.942 cm;临界摩擦速度约为0.34 m/s;2 m高度的起沙风速约为4.6 m/s。  相似文献   

Sensitivity of the Humboldt Current system to global warming: a downscaling experiment of the IPSL-CM4 model   总被引：1，自引：1，他引：0  

Vincent Echevin  Katerina Goubanova  Ali Belmadani  Boris Dewitte 《Climate Dynamics》2012,38(3-4):761-774

The impact of climate warming on the seasonal variability of the Humboldt Current system ocean dynamics is investigated. The IPSL-CM4 large scale ocean circulation resulting from two contrasted climate scenarios, the so-called Preindustrial and quadrupling CO₂, are downscaled using an eddy-resolving regional ocean circulation model. The intense surface heating by the atmosphere in the quadrupling CO₂ scenario leads to a strong increase of the surface density stratification, a thinner coastal jet, an enhanced Peru–Chile undercurrent, and an intensification of nearshore turbulence. Upwelling rates respond quasi-linearly to the change in wind stress associated with anthropogenic forcing, and show a moderate decrease in summer off Peru and a strong increase off Chile. Results from sensitivity experiments show that a 50% wind stress increase does not compensate for the surface warming resulting from heat flux forcing and that the associated mesoscale turbulence increase is a robust feature.  相似文献   

Neuro-fuzzy modelling in mining geochemistry: Identification of geochemical anomalies     

Mansour Ziaii  Ali A. Pouyan  Mahdi Ziaei 《Journal of Geochemical Exploration》2009

Local and mine scale exploration models for anomaly recognition within known ore fields are discussed. Traditional geochemical exploration methods are based on multivariate statistical analysis, metallometry, vertical geochemical zonality and criteria of natural field geochemical associations, which suffer several shortcomings, including lack of a geostatistical generalised approach for separating anomalies from background. These shortcomings make the interpretation process time consuming and costly. Fuzzy set theory, fuzzy logic and neural network techniques seem very well suited for typical mining geochemistry applications. The results, obtained from applying the proposed technique to a real scenario, reveals significant improvements, comparing the results obtained from applying multivariate statistical analysis. Computationally, the introduced technique makes possible, without exploration drilling, the distinction between blind mineralisation and zone of dispersed ore mineralisation. The methodology developed in this research study has been verified by testing it on various real-world mining geochemical projects.  相似文献   

An organic geochemical investigation on organic rich sediments from two Neogene formations in the Klias Peninsula area,West Sabah,Malaysia     

Amer M. Burgan  Che Aziz Ali 《中国地球化学学报》2009,28(3):264-270

Twenty organic rich outcrop samples from the Belait and Setap Shale formations in the Klias Peninsula area, West Sabah, were analysed by means of organic petrology and geochemical techniques. The aims of this study are to assess the type of organic matter, thermal maturity and established source rock characterization based primarily on Rock-Eval pyrolysis data. The shales of the Setap Shale Formation have TOC values varying from 0.6 wt%–1.54 wt% with a mean hydrogen index (HI) of 60.1 mg/g, whereas the shal...  相似文献   

Tectonic implications of felsic tuffs within the Lower Miocene Gangrinboche conglomerates,southern Tibet     

Jonathan C. Aitchison  Jason R. Ali  Angel Chan  Aileen M. Davis  Ching-Hua Lo 《Journal of Asian Earth Sciences》2009,34(3):287-297

Felsic tuffs are interbedded with the Gangrinboche conglomerates adjacent to the Yarlung Tsangpo suture zone in southern Tibet. Laser Ar/Ar dating of mineral separates indicates they are of Early Miocene age. Such tuffs are most likely an eruptive manifestation of geochemically indistinguishable coeval felsic (adakitic) intrusions that are widely reported across southern Tibet. The considerable lateral (E–W) extent of the Gangrinboche conglomerates and their depositional setting indicates sediment accumulation in an overall N–S compressional regime and thereby places important constraints on the tectonic setting in which magmatism initiated. The conglomerates were folded and truncated during back-thrusting associated with development of the north-directed Great Counter thrust. As N–S trending rifts associated with E–W extension of the Tibetan Plateau cut both the conglomerates and this thrust system it can be inferred that post-collisional volcanism is unlikely to have been genetically linked to later E–W extension. Early Miocene slab break-off beneath Tibet provides a model that appears to be consistent with petrogenesis of the associated magmatic suite, which requires a lowermost crust or lithospheric mantle generation, molasse accumulation, and uplift and emplacement of North Himalayan gneiss domes.  相似文献   

Flooding and its relationship with land cover change,population growth,and road density     

Mahfuzur Rahman  Chen Ningsheng  Golam Iftekhar Mahmud  Md Monirul Islam  Hamid Reza Pourghasemi  Hilal Ahmad  Jules Maurice Habumugisha  Rana Muhammad Ali Washakh  Mehtab Alam  Enlong Liu  Zheng Han  Huayong Ni  Tian Shufeng  Ashraf Dewan 《地学前缘(英文版)》2021,12(6):16-35

Bangladesh experiences frequent hydro-climatic disasters such as flooding.These disasters are believed to be associated with land use changes and climate variability.However,identifying the factors that lead to flooding is challenging.This study mapped flood susceptibility in the northeast region of Bangladesh using Bayesian regularization back propagation(BRBP)neural network,classification and regression trees(CART),a statistical model(STM)using the evidence belief function(EBF),and their ensemble models(EMs)for three time periods(2000,2014,and 2017).The accuracy of machine learning algorithms(MLAs),STM,and EMs were assessed by considering the area under the curve-receiver operating char-acteristic(AUC-ROC).Evaluation of the accuracy levels of the aforementioned algorithms revealed that EM4(BRBP-CART-EBF)outperformed(AUC＞90％)standalone and other ensemble models for the three time periods analyzed.Furthermore,this study investigated the relationships among land cover change(LCC),population growth(PG),road density(RD),and relative change of flooding(RCF)areas for the per-iod between 2000 and 2017.The results showed that areas with very high susceptibility to flooding increased by 19.72％between 2000 and 2017,while the PG rate increased by 51.68％over the same period.The Pearson correlation coefficient for RCF and RD was calculated to be 0.496.These findings highlight the significant association between floods and causative factors.The study findings could be valuable to policymakers and resource managers as they can lead to improvements in flood management and reduction in flood damage and risks.  相似文献