数字强震仪记录的长周期误差分析

对四种型号的数字强震仪作了振动台试验分析，发现加速度记录的背景噪声水平均较低，但均存在零线变动现象。所产生的长周期误差对加速度记录影响极小，但使积分位移产生很大的零线漂移，因而无法直接积分得到可靠的位移过程。在对不同校正方法进行了比较研究之后，提出了一种校正处理方法。     

井下地震仪的软定向

本文给出了井下地震仪软定向的原理及一般方法,并具体确定了菏泽台井下地震仪的方位;同时,文章对软定向的误差和精度进行了讨论。     

短周期地震仪在标定过程中需注意的几个问题

通过对短周期地震仪常数标定过程中几个重要环节的分析，说明了标定仪器的物理意义。由于采用了近似计算，所以对每个操作中需要注意的地方作了仔细交代，有助于实际工作。     

喀什台763长周期地震仪水平向抗干扰能力差的原因及改进

喀什台７６３长周期地震仪水平向抗干扰能力差的原因及改进赛来义，王居云，阿衣夏木，庄茂良，沈新雄（新疆维吾尔自治区喀什地震台，喀什，８４４０００）７６３长周期地震仪在全国已有２０多个台站安装试记，总的看来工作是正常的。垂直向记录一般都很好，抗干扰能力比...     

应变地震仪数据采集系统的研究

为了丰富应变仪器的信息量，研究了具有高速采集事件触发能力的应变地震仪数据采集系统。此采集系统除了 正常记录潮汐应变信息外，还具有记录应变地震波等非潮汐信息的能力。     

银川地震台CTS-1数字地震仪震级校正初探

主要分析讨论了2002年1月~2005年2月银川台数字地震仪测定的震级与中国数字地震台网观测报告震级的误差,给出银川台CTS-1数字地震仪震级的校正值,以提高银川台地震速报的精度。同时初步探讨分析了银川台数字地震仪震级误差的原因。     

大型水平向维歇尔地震仪的工作原理及其理论探讨

江苏省南京基准地震台现用的大型水平向维歇尔地震仪，是目前我国唯一的、世界上仅存的三台该型号仪器之一，该台仪器已有６０多年的历史，由于战乱及几经搬迁，仪器工作原理之类的原始资料丧失殆尽。本文试图填实这一空缺，并勘正此型仪器为倒立摆的现存说法。     

短周期烟记录地震仪技术改进试验研究

针对烟记录地震仪存在的问题，采取仅改动其放大器、电源与记录部分，利用现有拾震器和大滚筒记录器，投入少量资金，即可改造成适合台站使用的新型ＤＹＪ－１型短周期墨水记录地震仪。     

DD—1型短周期地震仪改制

本文介绍了改制后ＤＤ－１型地震仪放大器，稳频器，稳压器的工作原理，简述了其主要技术指标，并给出了仪器标定和试验结果，ＤＤ－１型短周期地震仪改制，是为了使仪器更好地适应地震预报与基础研究的观测需要而进行的，将改制后的仪器经室内测试标定和实际观测，并与沈阳地震基准台记录进行对比分析，证明改制后的ＤＤ－１型短周期地震仪主要技术指标与工作性能已达到规范的要求。     

宽频带数字地震记录仿真的应用

利用傅里叶分析法，把速度型宽频带数字地震记录变成台站人员所熟悉的长周期，中长周期模拟常规地震记录，分析人员能在仿真后的记录波形图上识别震相和计算震级。为地震台站用宽频带数字地震记录取代模拟记录提供了一种资料处理方法。     

GPS测量大气折射模型研究

在精密ＧＰＳ测量中,大气折射改正误差是最大的误差源之一。研究大的射理论,建立更加符合实地的模型,推导精确的改正公式,已成为ＧＰＳ测量研究中最重要的课题之一。本文对大层折射理论进行了深入研究,建立了新的在气层模型,推导出新的更精确的折射改正公式。     

Selection of time step for pseudodynamic testing

Although the step degree of nonlinearity has been introduced to conduct basic analysis and error propagation analysis for the pseudodynamic testing of nonlinear systems, it cannot be reliably used to select an appropriate time step before performing a pseudodynamic test. Therefore, a novel parameter of instantaneous degree of nonlinearity is introduced to monitor the stiffness change at the end of a time step, and can thus be used to evaluate numerical and error propagation properties for nonlinear systems. Based on these properties, it is possible to select an appropriate time step to conduct a pseudodynamic test in advance. This possibility is very important in pseudodynamic testing, since the use of an arbitrary time step might lead to unreliable results or even destroy the test specimen. In this paper, guidelines are proposed for choosing an appropriate time step for accurate integration of nonlinear systems. These guidelines require estimation of the maximum instantaneous degree of nonlinearity and the solution of the initial natural frequency. The Newmark explicit method is chosen for this study. All the analytical results and the guidelines proposed are thoroughly confirmed with numerical examples.     

Performance of the electrochemical ozone sonde OSR

Summary The accuracy of the electrochemical ozone sonde, type OSR, has been estimated by analysing tandem ozone soundings of the balloon-borne electrochemical ozone sonde OSR at the Lindenberg Observatory from May to November 1982. A negative bias, though not significant, has been observed above about 28 km for soundings having high single correction factors. Random errors are at their minimum just above the level of the maximum of ozone partial pressure, and reach their maximum in the troposphere. Except at heights above about 28 km the random error of ozone sondes is a factor 2 to 3 times less than the error of the short Umkehr method. Provided that soundings with too high correction factors are neglected, the ozone sonde OSR has an accuracy comparable to that of other Brewer type sondes.The maximum amount of information on the vertical ozone distribution can be drawn from sonde measurements in the lower stratosphere. A study is underway to improve the sensitivity of the sonde OSR and thus to further enhance its reliability.     

关于Rn－150固体氡气源分配剂量误差的讨论

本文从放射性平衡及理想气体有关定律出发，分析了Ｒｎ－１５０固体氡气源的标定原理，计算了源内含镭量及与之平衡状态下的氡气质量、原子数、体积及其产生的分压。讨论了影响Ｒｎ－１５０固体氡气源分配剂量精度的几种因素，及其误差修正方法。     

边坡振动台模型实验动位移的加速度时程积分探讨

受数据采集条件限制,振动台模型实验的速度和动位移时程一般由实测加速度时程信号进行积分得到。通过理论分析和实验实测数据计算,认为动位移的频域积分法误差来源是低频截止频率的选取,特别当低频频率接近零时,传统二阶频域积分可产生较大的动位移低频振荡和峰值误差。提出利用时域与频域混合的方法,即频域一时域混合积分法,来克服积分过程带来的误差,其在对加速度两次积分中,分别进行一次频域积分和一次时域积分。地震模拟振动实验的台面实测加速度数据积分与台面动位移计实测数据的对比表明,较之传统的二阶频域积分,采用频域一时域混合积分时误差可明显减小。     

智能误码测试仪简介

在数字遥测地震台网的信道设备研制和台站勘选工作中，常常需要几十个小时甚至几天连续不间断地进行数据传输效果测试。数据质量通常用误码率来表征。智能误码测试仪能自动将整个测试过程中的误码累计显示并定时分段打印留存，便于进行误码图样分析和研究。     

范家坝-临江断裂活动与1879年甘肃武都南8级地震的讨论

1879年甘肃武都南 8级地震发震断裂的确认是一个未决的问题。文中通过卫星影像解译、史料记载分析,认为沿文县东北水坑山北麓NEE向的范家坝 -临江断裂可能分布有该次地震的地表破裂带,因而,这一条断裂可能是该次地震的发震断裂。由此,可在发震断裂的产状变化、活动方式、地表破裂带长度、水平位错量大小及沿断裂的分布、断裂的区域归属、宏观震中位置、可能震级大小、震害分布等诸多方面取得一致     

Accuracy assessments of recent earth gravity models using crossover altimetry

Summary The calibrated variance-covariance matrices of the harmonic geopotential coefficients of the recent combined model JGM 2 has been tested and verified by independent crossover altimetry from TOPEX/Poseidon and ERS 1 using the Latitude Lumped Coefficients in the southern oceans area. Although orbits are not yet available for these missions with other recent models for which error matrices have been released, by comparison with JGM 2 results and field differences we also confirm that the error matrices for the satellite model GRIM 4S4p and the combined data model JGM 3 are also generally valid. Projections of these matrices for a variety of inclinations show that many unused orbits of even moderate altitude (≈ 800 km) will still yield trajectory crossover errors at a level of many tens of centimeters even with the latest orbitgeopotential models.     

LEAST-SQUARES FILTERS WITHOUT TRANSIENT ERRORS: AN EXAMINATION OF THE ERRORS IN LEAST-SQUARES FILTER DESIGN*

A new approach has been developed for the design of cross-equalization filters by the least-squares method. The filters estimated by this new exact method are subject to only two types of error: bias and random error. Cross-equalization filters estimated by a more conventional least-squares method are further subject to “transient error”. This type of error becomes important when designing filters from a data gate of a length comparable with the length of the filter, i.e., less than four times the length of the filter. The effect of altering various design parameters has been investigated for the new method. It has been found that the proportion of bias in the filter decreases as the effective filter length increases, whereas the random error in the filter decreases with increase in either the signal-to-noise ratio of the data or the ratio of the data duration to the filter length. The level of whitening applied to the auto-correlation matrix before inversion was not found to be a critical design parameter. Also, two techniques have been tested for reducing any anomalous d.c. component in the calculated filter.     

Synchronous retrieval of land surface temperature and emissivity

This is an old topic for more than ten years to retrieve land surface temperature (LST) from satellite data, but it has not been solved yet. At first, people tried to transplant traditional split window method of sea surface temperature (SST) to the retrieval of LST, but it was found that the emissivities of land surface (ε_i) must be involved in atmospheric correction. Then many different formulas appeared with assumption of emissivities known. In fact, emissivities of land surface with pixel size cannot be known beforehand because of various reasons, so in recent years the focus of attention has been transferred to retrieving emissivities (ε_i) and LST at the same time. Therefore, we have to solve missing equations problem. For this some people try to introduce middle infrared information, but new problems will be brought in which means that it is very difficult to describe middle infrared BRDF of targets with high accuracy and the scattering of atmospheric aerosol cannot be ignored. Therefore a different way is offered to solve this problem only using two thermo-infrared bands data based on three assumptions, constant emissivities in two measurements, and the same atmospheric parameters for neighbouring pixels and the difference of emissivity (Δε) of two channels can be known beforehand. Results of digital simulations show that it is possible to retrieve LST with its root mean square (RMS) of errors less than 1 K and RMS of relative error of ground radiance at 7% if the error of atmospheric temperature at ± 2°C and the relative error of atmospheric water vapor at ± 10% can be satisfied. Results have been confirmed by initial field test. Project supported by the National Natural Science Foundation of China (Grant No. 49471056) and China’s National Key Basic Research Plan.