关于若干化探数据处理方法的讨论

化探数据处理中的系统误差校正和异常识别方法很多，移动标准化法、分区标准化法和衬度系数法是其中的几种方法，主要对这几种方法做了简单的介绍并对其效果进行了对比，最后着重讨论了C型变换法的优点。     

Three-dimensional Q structure in Jiashi earthquake region of Xinjiang

3-D S-waveQ structure in Jiashi earthquake region is inverted based on the attenuation of seismic waves recorded from earthquakes in this region in 1998 by the Research Center of Exploration Geophysics (RCEG), CSB, and a rough configuration of deep crustal faults in the earthquake region is presented. First, amplitude spectra of S-waves are extracted from 450 carefully-chosen earthquake records, called observed amplitude spectra. Then, after instrumental and site effect correction, theoretical amplitude spectra are made to fit observed amplitude spectra with nonlinear damped least-squares method to get the observed travel time overQ, provided that earthquake sources conform to Brune’s disk dislocation model. Finally, by 3-D ray tracing method, theoretical travel time overQ is made to fit observed travel time overQ with nonlinear damped least-squares method. In the course of fitting, the velocity model, which is obtained by 3-D travel time tomography, remains unchanged, while onlyQ model is modified. When fitting came to the given accuracy, the ultimateQ model is obtained. The result shows that an NE-trending lowQ zone exists at the depths of 10–18 km, and an NW-trending lowQ zone exists at the depths of 12–18 km. These roughly coincide with the NE-trending and the NW-trending low velocity zones revealed by other scientists. The difference is that the lowQ zones have a wider range than the low velocity zones. Foundation item: Joint Seismological Science Foundation of China (957-07-414) and State Key Basic Research Development and Programming Project (95-13-02-02). Contribution No. RCEG200105, Research Center of Exploration Geophysics, China Seismological Bureau.     

多波束测深系统的高精度差分GPS数据实时优化

多波束海底地形探测是目前世界上最为先进的海底地形探测方法.高精度的差分GPS定位是实现多波束系统高精度测深的最基本前提.在海上探测作业过程中,由于客观原因,差分GPS数据存在偶然误差,影响多波束测深精度.本文提出对差分GPS数据进行航速、航向平滑处理、误差定位点位置推算的实时优化方法和数学模型,并给出实际实现的例子.     

中、低空机载成像光谱图像的几何校正研究

本文针对我国上海技术物理所研制的OMIS机载128道成像光谱系统试飞所获取的图像、定位和飞行姿态等数据，进行了图像几何修正处理和衫软件开发研究。详细分析了该系统所获取的定位与飞行姿态数据及存在的问题，并制定了相应的处理方案。根据该系统提供的各种参数，建立了航空高光谱图像单因素几何校正模型和几何畸变综合校正方法。对该系统在辽东湾地区试验飞行获取的10条航带图像进行几何校正和多航带镶嵌处理，效果理想。     

大气谱模式中质量守恒格式的研究

当前在世界上广泛采用的谱模式，是以地面气压ps取对数作为展谱变量，模式大气总质量不守恒。本文研究这样的问题，提出了以热力学变量比容α代替温度变量T的方法，并以地面气压ps本身作为展谱变量，这样可以保持大气总质量守恒。同时，由于以α作展谱变量，可使重要项气压梯度项为二阶变量组成，截谱后，不会出现混淆误差。计算结果表明，这样改变后，大气总质量保持守恒。同时消除了混淆误差的出现。     

实际预报可预报性的时空依赖性分析

本文利用国家气象中心1990年1月1日至1992年2月29日的1～5 d、500 hPa高度场业务预报结果研究了不同球谐函数谱分量和经验正交函数(EOF)谱分量的可预报性。对球谐函数谱分量的研究表明可预报性并不是随着空间尺度的增加呈现单调的递减关系，主要表现为在总波数n等于5附近具有最大可预报性。可预报性主要依赖于总波数n，经卷大圆上的波数和纬向圆周上的波数对可预报性具有完全相同的重要意义。对EOF谱分量的分析表明，随着EOF指数(即序号数)的增大，可预报性依次减小。从EOF和球谐函数的关系发现前几个EOF分量正是对应着最可预报的球谐函数分量。进一步分析表明，最可预报的分量对应大气运动的慢变流型。这些结果对如何使用数值预报产品以及如何进行延伸预报具有重要意义。     

The Q value variations in the preparing pro－cess of rock rupture

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Study on the characteristics of crust－mantle transition zone in Western Yunnan Province

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Modelling of ground motion in the vicinity of massive structures

A two-dimensional elastic Chebyshev spectral element method (SPEM) is used to model the seismic wavefield within a massive structure and in its vicinity. We consider 2-D models where a linear elastic structure, with quadrangular cross-section, resting on an elastic homogeneous half-space, is impinged upon by the waves generated by a surface impulse at some distance. The scattering of Rayleigh waves and the response of the structure are extensively analysed in a parametric way, varying size, mechanical parameters and shape of the load. Some of the models considered are representative of embankments and earth dams. The simulation shows that some models resonate, storing part of the incoming energy. With realistic parameters, the lowest resonance frequency is due to pure shear deformation and is controlled by the shear velocity and height of the load. Flexural modes are excited only at higher frequencies. The acceleration at the top of the structure may be five/seven times higher than at the base, depending on the mass of the structure. The gradual release of trapped energy produces a ground roll lasting several seconds after the wave front has passed. The ground-roll amplitude depends on the sturcture's mass and can be as large as 30% of the peak acceleration. Outside resonance conditions, the ground motion is almost unaffected by the presence of the artefact; the horizontal motion on top of it is nearly twice the motion at ground level. Similar results should be expected when the incident field is an upcoming shear wave. A qualitative discussion shows that the presence of anelastic attenuation in the embankment does not significantly alter the preceding conclusions, unless it is of very low values (e.g. Q < 15).The modelling results that we discuss indicate that the soil-structure interaction may substantially alter the ‘free-field’ ground motion. From a practical point of view, the main conclusions are: (1) careful analysis is necessary when interpreting seismic records collected in the vicinity of large artefacts; (2) seismic hazard at a site may depend on the presence of man-made structures such as embankments, dams, tall and massive buildings.