VP型垂直摆倾斜仪观测频带的分析及改进

从仪器原理、传递函数和观测数据等方面分析目前在网进行1 Hz采样的VP型垂直摆倾斜仪在2~60 s周期内的频率特性,认为该仪器可以观测到频带内的信号变化,但因处于过渡带,观测幅度较真实幅度削弱约20~40 dB。对VP型垂直摆倾斜仪观测频带进行拓展,使2~60 s周期内的观测信号由之前的过渡带进入到仪器的通频带,结果与相同采样率的其他定点形变仪器的观测效果相同,将地倾斜观测量转换为加速度表达后,其幅频特性符合全球地震背景噪声模型。改进后的VP型垂直摆倾斜仪对于远距离震级不大的同震体波震相记录效果略优于改进前,但受地脉动影响,在识别非地脉动信号时需要采用更精细的方法和手段来提高识别效果。     

新疆沙漠地区地表宽波段比辐射率遥感估算

地表比辐射率是估算地表温度以及地表长波辐射的一个重要参数,为了解决遥感影像反演地表比辐射率在裸地的精度不足问题,本文在新疆沙漠地区利用2类数据：① 傅里叶变换热红外光谱仪（FTIR）数据,在2013年、2014年秋天沿2条穿越塔克拉玛干沙漠的沙漠公路测量得到25个点的地表比辐射率数据;② 与FTIR数据同时期的MODIS温度/比辐射率数据MOD11A1、MOD11B1和反射率数据MOD09GA以及反照率数据MCD3A3,利用这2类数据为数据源,估算新疆沙漠地表比辐射率。首先,重新估算了基于MODIS宽波段比辐射率（BroadBand Emissivity, BBE）方程的系数和基于GLASS（Global L And Surface Satellite）BBE方程的系数,由此获得了GLASS BBE和MODIS BBE的修正方程。其次,将修正前后的GLASS BBE与FTIR和MODIS BBE作对比,发现其精度显著提高：① 与FTIR数据对比,修正前后的GLASS BBE方程的决定系数R²值从0.42增加到0.95,均方根误差（RMSE）和偏差（Bias）分别减少了1和3个数量级;② 与MODIS BBE方程数据对比,修正前后的GLASS BBE的R²值从0.69增加到0.91,RMSE和Bias分别减少了1和2个数量级。因此,修正后的基于GLASS和MODIS的BBE方程,极大地提高了遥感影像对裸地尤其是沙漠地区地表比辐射率的反演精度。使用修正后的GLASS BBE方程反演出新疆3个沙漠地区的BBE分布特征。结果表明,塔克拉玛干沙漠由于土地类型较为单一,其BBE值主要为0.88~0.92,而古尔班通古特沙漠以及库姆塔格沙漠受到地形、植被等的影响,BBE值稍微偏高,分别为0.89~0.95和0.89~0.94,沙漠周边稀疏植被区及其边缘地区的值范围为0.95~1.00。本文基于GLASS和MODIS的适用于新疆沙漠的BBE方程,为陆面过程的研究与模拟提供了支持。     

DQK－1型磁变仪倾斜仪监控器

70年代的仪器设备受当时的技术和材料的限制，存在着多种弊端。提高观测精度，改善内在质量问题势在必行。本从前兆台网的实际出发，把地球物理与电子技术相结合，把维修经验及仪器研制相结合，运用功率电子学和自动控制理论，试制成功“DQK-1型磁变仪倾斜仪监控器”，把地磁、地倾斜等前兆观测项目中的每天3次人工检查仪器改为实时监控，为确保地震前兆观测的可靠性和连续性提供了硬件保障。     

基于非线性最小二乘法的石英水平摆倾斜仪格值标定

采用非线性最小二乘法对石英水平摆倾斜仪格值标定的秒采样数据进行拟合。通过Levenberg-Marquardt算法实现迭代计算过程,准确求解光记录位移信号参数并计算标定格值。仿真和台站标定实验结果表明,采用非线性最小二乘法计算倾斜仪秒采样数据的标定格值与倾斜仪校准格值的一致性较好。     

Ocean bottom tiltmeter with acoustic data retrieval system implanted by a submersible

Sensitive Ocean Bottom Implanted Tiltmeters (OBITs) with a sophisticated data retrieval system have been developed in order to observe directly the subduction of oceanic lithosphere. The OBIT is the first long-term geophysical instrument which was designed to be deployed by a manned deep-sea submersible. When the OBIT is put on oceanic lithosphere which is bending and is about to subduct under a deep sea trench, the OBIT records the subduction by observing the tilt of the surface of the lithosphere. The OBIT system has a sensitivity of 10^-8 radian, which is enough to detect the ongoing subduction in months or years. The OBIT may give an answer to the question whether there are fluctuations in the subduction rate.Two OBITs were successfully deployed on a seaward slope of the Kuril Trench by the newly built French deep submersible, Nautile. The OBITs were installed on the northwest shoulder of Erimo seamount, at a depth of 3930 m, in the Kuril Trench. In order to attain stable long-term observations of crustal deformations, the sensing unit was cemented onto bare rock by mortar. We have not yet had an opportunity to recover the data.The life of the instruments is expected to be more than five years. An acoustic data transmission system has been developed for the OBIT data recovery. The stored data can be retrieved at any moment during the observation period, with no need to retrieve the instruments nor to interrupt the observation, by use of the acoustic system. The acoustic system has a high data transmission rate as well as extremely low power consumption. This will be the first long-term crustal deformation measurement on the sea floor.     

The Bremen ocean bottom tiltmeter (OBT) – a technical article on a new instrument to monitor deep sea floor deformation and seismicity level

The Bremen ocean bottom tiltmeter is a new 6000 m-depth deep sea instrument for autonomous observation of sea floor tilt with signal periods longer than 7.5 s. The instrument also records vertical acceleration in the frequency range from DC to 1 Hz. The tiltmeter has an Applied Geomechanics Inc. 756 wide angle biaxial bubble tilt sensor with a resolution of 1.0μ rad (0.2 arc second). A Kistler Corp. MEMS accelerometer of type Servo K-Beam 8330A2.5 with about 10⁻⁵m/s² resolution is used for the acceleration measurements. An Oceanographic Embedded Systems AD24 24 bit Sigma-Delta converter, which is controlled by a low-power Persistor Inc. embedded computer system of type CF 2, samples the data. The duration of tiltmeter operation is more than one year, which is controlled by the battery life. In our design the tiltmeter does not need active leveling devices, i.e., servo motors or other moving components to adjust sensors or frame. We designed the instrument for deployments by means of a remote operated vehicle. Since May 2005 the Bremen ocean bottom tiltmeter has recorded sea floor deformation and seismicity level in the Logatchev hydrothermal vent field, Mid-Atlantic Ridge. The tiltmeter is a part of the monitoring system of project ‘Logatchev Long-Term Environmental Monitoring,’ called LOLEM, of the German research program with the name ‘Schwerpunktprogramm 1144: Vom Mantel zum Ozean.’     

成都数字遥测台网微波中转设计中考虑的几个因素

将模拟地震遥测台网改为数字地震遥测台网，微波设备的改造是当务之急。根据经济实力选购合适的微波设备，了解所选设备的性能以及传输质量，使之适合成都传输台网已存在的设备条件。     

中美青藏高原数字宽频带地震观测

1991年7月至1992年7月,中美合作在青藏高原进行了天然地震观测。布设了由11个台站组成的台阵,其中7个台站由北至南分布在青藏公路格尔木至拉萨段沿线,2个分别在其两侧,另外2个在青藏高原东部。此台阵使用REF TEK 72A-02记录器和宽频带STS-2地震计,进行事件触发及连续记录。此次观测为在青藏高原内采集地震数据提供了极好的机会。     

兰州形变台水管倾斜仪映震能力的分析研究

以兰州形变台FSQ水管倾斜仪1987年以来的观测资料为研究对象,从非潮汐和潮汐两个方面,利用形态分析法、曲线拟合、残差分析、潮汐因子动态分析、半日波大潮椭圆以及潮汐偏角分析等方法对数据进行了系统分析,研究了观测异常与地震的关系。结果表明该台的水管倾斜仪对邻区的中强地震有很好的中、短期响应。