多尺度分解在地震信号处理中的应用

利用小波分析中的多尺度分解及信号消噪技术，对记录不清、信噪比小、震相无法辨认的地震信号进行处理。结果表明：多尺度分解在弱震信号提取和弱震相的识别等方面有很好的效果。     

Aerosol polarized phase function and single-scattering albedo retrieved from ground-based measurements

Aerosol optical parameters, polarized phase function and single-scattering albdeo, have been retrieved from ground-based sun photometer measurements in Beijing 2003. The measured aerosol optical thickness varies from 0.12 to 0.77 with an average value of 0.39. The measured Ångström coefficient ranges from 0.75 to 1.47 with an average value of 1.21. The retrieved single-scattering albedo at 870 nm is within the 0.76–0.94 range and the average value is 0.85, suggests there are considerable aerosol absorptions in Beijing. The maximum value of retrieved polarized phase function at 870 nm ranges from 0.068 to 0.225 with an average value of 0.16, and it illustrates good correlations with the Ångström coefficient, i.e. the relative size of aerosol particles. Analyses of measurements and theoretical calculations show the polarized phase function is sensitive to aerosol size distribution and complex refractive index, especially the imaginary part of the refractive index which denotes aerosol light absorbing effects. These results suggest that the polarized phase function is an effective and unique aerosol optical parameter and is able to improve the retrieval of aerosol physical properties.     

Turbulent Pressure Statistics in the Atmospheric Boundary Layer from Large-Eddy Simulation

We use large-eddy simulation (LES) to study the turbulent pressure field in atmospheric boundary layers with free convection, forced convection, and stable stratification. We use the Poisson equation for pressure to represent the pressure field as the sum of mean-shear, turbulence–turbulence, subfilter-scale, Coriolis, and buoyancy contributions. We isolate these contributions and study them separately. We find that in the energy-containing range in the free-convection case the turbulence–turbulence pressure dominates over the entire boundary layer. That part dominates also up to midlayer in the forced-convection case; above that the mean-shear pressure dominates. In the stable case the mean-shear pressure dominates over the entire boundary layer.We find evidence of an inertial subrange in the pressure spectrum in the free and forced-convection cases; it is dominated by the turbulence–turbulence pressure and has a three-dimensional spectral constant of about 4.0. This agrees well with quasi-Gaussian predictions but is a factor of 2 less than recent results from direct numerical simulations at moderate Reynolds numbers. Measurements of the inertial subrange pressure spectral constant at high Reynolds numbers, which might now be possible, would be most useful.     

福建及台湾海峡地震预警工程架构探索

福建及台湾海峡是海陆板块碰撞到板内地震活动过渡带 ,东侧毗邻台湾板缘地震带 ,西侧为福建内陆板内地震活动区。这是得天独厚的观测研究大陆边缘地震构造带强震活动及板块动力学的良好地域。当前 ,我国进入全面建设小康社会历史时期 ,为防御地震造成社会灾害 ,实现以人为本 ,防患于未然 ,势必需要建构一个实用化的地震预警工程及其机制。本文即是在对福建及台湾海峡近 30多年以来观测研究的基础上 ,提出应用现代空间技术、数字地震、计算机网络等技术架构地震预警工程与机制的一种设想。     

主键约束在数字化前兆数据服务软件中的关键运用

数字化前兆数据库是一个分布式网络数据库SQLServer,数据库的建成运用为预报人员的日常数据分析提供了一个准确的、完整的资源平台。为考虑数据库设计完整性规则 ,本文着重讲述建立两套前兆数据库的过程中 ,主键约束在数字化前兆数据服务软件EPDS的建库及入库中起的重要作用。     

桩基沉降量的灰色预测

利用实测的桩基静载试验数据 ,用灰色系统理论建立桩基沉降量的灰色GM(1,1)预测模型 ,可以模拟桩基静载试验P s曲线的未知部分。研究结果表明 ,建立的GM(1,1)模型可有效预测桩基沉降量 ,对进一步分析桩基的承载性能有理论与实际意义。     

水域静力触探设备的研制和应用

为详细了解崇明越江通道南港隧道段地层情况 ,设计要求提供长江水域静探资料。简介了我院水域静力触探设备的研制和应用情况     

Strong earthquake activity all over the world and strong moderate earthquake activity within and near China(October,2003 ～November,2003)

Illustration All the data in this catalog are chosen from the Preliminary Seismological Report of Chinese Seismic Stations (abbreviated to Monthly Report). The catalog includes the events of M≥4.7 in and near China and M≥6 all over the world. The Monthly Report is monthly compiled by the Ninth Section of Institute of Geophysics, China Earthquake Administration (CEA).     

Estimation of Site Effects in Beijing City

— For the realistic modeling of the seismic ground motion in lateral heterogeneous anelastic media, the database of 3-D geophysical structures for Beijing City has been built up to model the seismic ground motion in the City, caused by the 1976 Tangshan and the 1998 Zhangbei earthquakes. The hybrid method, which combines the modal summation and the finite-difference algorithms, is used in the simulation. The modeling of the seismic ground motion, for both the Tangshan and the Zhangbei earthquakes, shows that the thick Quaternary sedimentary cover amplifies the peak values and increases the duration of the seismic ground motion in the northwestern part of the City. Therefore the thickness of the Quaternary sediments in Beijing City is the key factor controling the local ground effects. Four zones are defined on the base of the different thickness of the Quaternary sediments. The response spectra for each zone are computed, indicating that peak spectral values as high as 0.1 g are compatible with past seismicity and can be well exceeded if an event similar to the 1697 Sanhe-Pinggu occurs.