新疆阿尔泰克因布拉克铜锌矿床地质特征及成矿作用

克因布拉克中型铜锌矿床赋存于早二叠世花岗岩外接触带的上志留统-下泥盆统康布铁堡组黑云石英片岩、变质石英砂岩中。矿床的形成经历了夕卡岩期、热液期和表生期,铜锌矿主要形成于热液期。矿石中石英和方解石流体包裹体划分为H_2O-NaCl型和H_2O-CO_2(±CH_4/N_2)-NaCl型。成矿温度变化于146～448℃,在170℃、270℃和350℃出现峰值;流体盐度变化于0.2%～46.9%NaCl_(eq),峰值为1.5%NaCl_(eq)和5.5%NaCl_(eq);流体的密度0.55～1.19g/cm~3。硫化物的δ~(34)S集中变化于-8.4‰～1.9‰,峰值为0‰,表明硫来自岩浆。石英和方解石δD_(SMOW)介于-130‰～-79‰,δ~(18)O_(SMOW)值介于8.0‰～11.6‰,δ~(18)O_(H2O)值为-1.7‰～4.43‰,表明成矿流体主要是岩浆水,混合大气降水。方解石中δ~(13)C_(PDB)变化于-5.3‰～-1.1‰,暗示碳来自花岗质岩浆。成矿时代为早中二叠世,成矿作用与花岗质岩浆期后的热液活动有关。     

高光谱数据在数据库中的高效存储技术研究

通过分析高光谱数据的特点 ,结合数据库系统开发实践 ,提出了高光谱数据集 ,包括图像、光谱、属性等 ,在关系数据库中的存储规范。结合ORACLE数据平台 ,提出了 3种高光谱数据的存储模式 ,并结合应用实例进行对比 ,分析了各自的优缺点以及适用条件。     

Advances in urban information extraction from high-resolution remote sensing imagery

The study of urban area is one of the hottest research topics in the field of remote sensing. With the accumulation of high-resolution(HR) remote sensing data and emerging of new satellite sensors, HR observation of urban areas has become increasingly possible, which provides us with more elaborate urban information. However, the strong heterogeneity in the spectral and spatial domain of HR imagery brings great challenges to urban remote sensing. In recent years, numerous approaches were proposed to deal with HR image interpretation over complex urban scenes, including a series of features from low level to high level, as well as state-of-the-art methods depicting not only the urban extent, but also the intra-urban variations. In this paper, we aim to summarize the major advances in HR urban remote sensing from the aspects of feature representation and information extraction. Moreover, the future trends are discussed from the perspectives of methodology, urban structure and pattern characterization, big data challenge, and global mapping.     

Feasibility of signal enhancement with multiple grounded‐wire sources for a frequency‐domain electromagnetic survey

Frequency‐domain electromagnetic methods with a grounded‐wire source are powerful tools in geophysical exploration. However, the signal may be too weak to guarantee the quality of survey data in complex electromagnetic environments, especially when the receiver is located in the air for the newly developed grounded‐source airborne frequency‐domain electromagnetic method. In this paper, a signal enhancement method with multiple sources is proposed to solve this problem. To evaluate the signal enhancement effect, we compared the signals generated by a single source and multiple sources with equal electric moment. The signal differences caused by synchronisation error and separation distance between source elements were analysed, and the methods to achieve maximum signal were introduced. Besides, we discussed the interaction between adjacent source elements to ensure the system safety, including the changes in output current and the safe distance between two sources using a dual‐source model. Lastly, a comprehensive field experiment was designed and conducted to test the multiple‐source method. The data processing results are comparable for single and dual sources, and the signal‐to‐noise ratio of dual source is higher in the field test. The subsurface resistivity structure at the test site is consistent with the previous controlled‐source audio‐frequency magnetotellurics method. These results show that signal enhancement with multiple sources is feasible. This study provides guidance to the application of multiple sources in field surveys when the survey environment is complex and rigorous.     

Discussion on several important problems in earthquake-related electromagnetic disturbance monitoring in China

Earthquake-related electromagnetic observation aims at finding abnormal electromagnetic variation associated with earthquake possibly. The existing studies have proved that this method is, to a large extent, effective in short-term and impending earthquake predication. This paper summarizes progress and discusses some related problems in this field. Some requirements for observation system have been proposed to improve monitoring level. As a case observation using the reformed observation system in Jinghai seismologic station, Tianjin, some results are given.     

30 m global impervious surface area dynamics and urban expansion pattern observed by Landsat satellites: From 1972 to 2019

Using more than three million Landsat satellite images, this research developed the first global impervious surface area (GISA) dataset from 1972 to 2019. Based on 120,777 independent and random reference sites from 270 cities all over the world, the omission error, commission error, and F-score of GISA are 5.16%, 0.82%, and 0.954, respectively. Compared to the existing global datasets, the merits of GISA include: (1) It provided the global ISA maps before the year of 1985, and showed the longest time span (1972–2019) and the highest accuracy (in terms of a large number of randomly selected and third-party validation sample sets); (2) it presented a new global ISA mapping method including a semi-automatic global sample collection, a locally adaptive classification strategy, and a spatio-temporal post-processing procedure; and (3) it extracted ISA from the whole global land area (not from an urban mask) and hence reduced the underestimation. Moreover, on the basis of GISA, the long time series global urban expansion pattern (GUEP) has been calculated for the first time, and the pattern of continents and representative countries were analyzed. The two new datasets (GISA and GUEP) produced in this study can contribute to further understanding on the human’s utilization and reformation to nature during the past half century, and can be freely download from http://irsip.whu.edu.cn/resources/dataweb.php.

     

Alternative Fuzzy Cluster segmentation of remote sensing images based on Adaptive Genetic Algorithm

Remote sensing image segmentation is the basis of image understanding and analysis. However, the precision and the speed of segmentation can not meet the need of image analysis, due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm (AGA) and Alternative Fuzzy C-Means (AFCM). Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased, and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means (FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.     

青岛市水环境问题及防治对策

青岛是我国缺水城市之一。但本已紧缺的水资源却存在着水质污染、开采漏斗、海（咸）水入侵及高氟水等一系列水环境问题。文中分析了其发生原因、危害程度及发展趋势,并提出了综合治理建议。     

凹坑地形风流结构对污染物散布的模拟研究

利用建立的三维非静力高分辨率高阶湍流闭合模式与随机游动扩散模式研究了一个深凹露天矿区污染物散布的规律,同时在风洞中进行了示踪实验。结果表明,由于凹坑内复环流结构的存在,使得坑内污染物浓度较大,且浓度最大值出现在源的上风侧。数值试验与风洞试验结果吻合较好。     

肃南5.7级地震过程剪切波分裂特征

剪切波分裂应用于地震预报中的３个主要困难是：（１）如何自动定量识别剪切波快慢波到时；（２）用以认识其基本特征的震例太少；（３）因各次地震的复杂性，对所给剪切波分裂结果难以给出恰当的解释，本文研究了１９８８年１１月２２日甘肃肃南５．７级地震过程剪切波分裂的特征。所用资料为１９８８年８月到１９９０年８月中法合作张掖数字台网的记录。通过对张掖～肃南地区地壳结构模型的研究，确认了所用各次地震的真实出射角基