Dereverberation of marine reflection seismic data by a spatial combination of predictive deconvolution and velocity filtering

Contamination of seismic reflection records at early times by first-order water reverberations can be especially severe during survey operations over hard and flat sea floors on the continental shelf or in lake environments. A new dereverberation scheme based on two classical techniques — predictive deconvolution and velocity filtering — has been developed to address this problem. The techniques are combined spatially to take advantage of their complementary offset- and time-dependent properties. Stage I of the scheme consists of applying predictive deconvolution at short offset. The data are previously conditioned by a normal moveout correction with the water velocity which restores the periodicity of the reverberations in the offset-time plane and enhances the performance of deconvolution. Stage II of the scheme involves velocity filtering in the common-midpoint domain which is particularly effective at long offset where the moveout difference between primary reflections and reverberations is largest. The dereverberation scheme is well suited for the initial processing of large volumes of data due to the general availability of cost-effective deconvolution and velocity filtering algorithms in seismic processing software packages. Practical implementation issues are illustrated by a field example from the GLIMPCE survey in Lake Superior.Lithoprobe Publication No. 475.     

Using Topological Relationships to Inform a Data Integration Process

When spatial datasets are overlaid, corresponding features do not always coincide. This may be a result of the datasets having differing quality characteristics, being captured at different scales or perhaps being in different projections or datums. Data integration methods have been developed to bring such datasets into alignment. Although these methods attempt to maintain topological relationships within each dataset, spatial relationships between features in different datasets are generally not considered. The preservation of inter‐dataset topology is a research area of considerable current interest. This research addresses the preservation of topology within a data integration process. It describes the functional models established to represent a number of spatial relationships as observation equations. These are used to provide additional information concerning the relative positions of features. Since many topological relationships are best modelled as inequalities, an algorithm is developed to accommodate such relationships. The method, based on least squares with inequalities (LSI), is tested on simulated and real datasets. Results are presented to illustrate the optimal positioning solutions determined using all of the available information. In addition, updated quality parameters are provided at the level of the individual coordinate, enabling communication of local variation in the resultant quality of the integrated datasets.     

暖切变型江淮梅雨锋结构及其形成和维持机制

对在1991年7月上旬特别稳定的梅雨形势下持续10天的特大暴雨期作了合成和典型过程研究,并进一步探讨了暖切变型江淮梅雨锋天气系统模型。它在自由大气层表现为结构竖立的相当正压切变线和一种不同于经典地转动量近似的带状准二维运动场。边界层的浅层锋生倾斜环流以及偏于切变线轴以南的Ekman抽吸与自由大气层中基本上由积云对流加热驱动的竖直环流相互依存和耦合,造成持续的大暴雨。这种系统的初生和中断后复苏的机制可能是由斜压性极弱的副热带高空东移的短波扰动在低层“湿度锋”带紧南侧触发导致的一种带状CISK。     

Micaps数据处理模块的维护与二次开发

结合 Micaps系统中数据处理模块的维护经验 ,针对其存在的问题提出了相应的解决措施 ;结合本地需求进行了二次开发     

基于预测控制的结构振动半主动控制研究

建立了半主动控制系统的理论模型，分析了半主动控制机理，并结合现代控制理论，将预测控制应用于结构半主动控制中，提出了在线预测控制算法，建立了预测模型，并成功的解决了时滞问题，最后作了计算机仿真分析，证明该系统有较好的控制效果。将预测控制思想应用于结构半主动控制中，为结构控制注入了新的思路，通过研究及仿真分析也说明了这种思想是可行的并且具有很大的发展前途。     

河南省短期区域性暴雨动力诊断及综合预报方案

介介绍了（１）用Ｔ６３数值预报产品对河南省省６－８月区域性暴雨进行物理量诊断分析。（２）用人工智能研制的河南省６－８月分片大－暴雨短短期自动化预报系统与用Ｔ６３数值预报产品资料采用逐步回归分析法和预测误差平方和最不上准则两种选取回归自变量的方法，建立处分片预报方程的综合判别预报。（３）在１９９５，１９９６年７－８月业务预报中试验结果。     

正确使用X—CT球管的技术探讨

本文报道了我院连续六只Ｘ－ＣＴ球管的使用情况。寿命最长的曝光达３５８３００秒，而最短的只有１３５０００秒，其主要原因是缺乏正确地使用和维护知识，要想延长球管使用寿命，首先需加强对使用人员的专业素质训练，其次，在保证图像质量的前提下，降低ｍＡｓ；第三，保持扫描室恒业的温湿度；第四，定期检查球管的冷却散热系统。     

21世纪中国地质灾害防治形势与减灾战略思考

文章论述了21世纪中国地质灾害减灾面临的形势是既存在许多有利条件又存在多方面困难而面临严重挑战。提出21世纪地质灾害减灾战略：1．建立地质灾害防治安全维护体系；2．优先安排西部地区地质灾害防治工程，实施地质灾害风险管理；3．建立矿山地质灾害防治监督管理体系；4．城市地质灾害防治与土地利用相结合；5．加强我国地质环境监测与网站建设；6．针对地质灾害区域分布规律，采取分区减灾对策；7．加大地质灾害防治投入力度。     

北方集中供热系统气象风险评估初探

供热管网爆裂、跑冒滴漏是北方集中供热城市面临的常见问题,供热管网出现大型故障往往是在室外寒冷的隆冬时节,如果间断或限额供热时间过长,将会造成严重的社会和经济影响。同时在极端低温情况下,可能会造成热源供应不足,出现限额供热现象,不能保证室内舒适度,影响人们的正常生活。本文提出了能源供应气象风险评估和热网维修寒冷风险评估方法,并进行了案例评估,以期为未来进行相关风险评估提供参考。     

淮河流域(河南段)连续性暴雨天气分型及环流背景

利用19812016年68月河南省淮河流域64个国家自动观测站逐日2020时日降水量资料、常规高空探测和地面观测资料等对淮河流域连续性暴雨时间分布特征、影响系统等进行分析和天气分型,结果表明:1)36年淮河流域共发生45次连续性暴雨,2000年的最多,19982008年是高发期,近10年较少,年出现次数无明显减少趋势,存在2~4年和4~6年两个周期;7月连续性暴雨次数最多,6月的最少,旬分布呈正态分布;最长连续时间5天,连续2天的最多。2)影响系统主要有切变线和高低空急流,高空急流在方向转换的过程中,降水有24h左右的减弱期,低空急流有明显的日变化特征,夜间加强,白天减弱。3)连续性暴雨按照500hPa影响系统,分为低槽型、副高边缘型、西北低涡型三类。4)以不同类型的3次典型连续性暴雨为例,从大尺度环流背景、高度距平场、水汽输送、高低空急流等方面探讨了连续性暴雨的维持成因,3次连续性暴雨的发生与异常的500hPa大气环流、高低空急流、切变线和持续偏强的水汽输送等有关。