双阳台DSQ型水管倾斜仪异常分析

双阳地震台DSQ型水管倾斜仪NS分量自2019年10月以来出现加速S倾打破年变形态的异常变化情况.为此对该测项仪器观测状态、观测环境变化、观测台站附近干扰等因素进行科学合理的分析研究,综合分析认为双阳台水管倾斜仪NS分量S倾加速变化为前兆异常.     

乌兰浩特地震台DSQ型水管倾斜仪干扰因素分析

选用2017年4月到2019年4月乌兰浩特地震台DSQ型水管倾斜仪观测数据,总结自然环境、人为及场地干扰事件,并挑选典型干扰事件进行详细分析。结果表明,观测数据受自然环境干扰时主要表现为噪声大现象,受人为干扰时会出现数据突跳,受场地环境干扰时会出现数据畸变。通过对各类典型干扰的分析,期望为同行就DSQ型水管倾斜仪观测数据的干扰识别及处理提供参考。     

水管倾斜仪电灵敏度的标定调试经验

根据以往维护水管倾斜仪的一些经验，介绍了在DSQ水管倾斜仪的标定过程中，调整换能器电压灵敏度的一些技巧。     

水管倾斜仪的快速标定方法

根据以前维护水管倾斜仪的一些经验,总结了一套快速标定水管仪的方法,在牡丹江地震台取得了成功。     

南平地震台水管倾斜仪常见故障分析及检修

文章在介绍DSQ型水管倾斜仪基本原理及系统结构的基础上,结合南平地震台多年的维修维护经验,着重对水管倾斜仪的常见故障进行分析,介绍检修方法,为其他地震台站同类仪器的维护检修提供参考。     

数字倾斜仪资料质量跟踪与映震效能研究

通过跟踪分析湖州地震台数字化水管倾斜仪和垂直摆倾斜仪连续2年的资料质量,发现水管倾斜仪观测精度高于垂直摆倾斜仪,并且资料稳定性逐年提高。从映震效能看,水管倾斜仪同震响应幅度远大于垂直摆,水管倾斜仪的自振周期远大于垂直摆倾斜仪而接近远震面波的周期,形成谐振,但两者的同震响应时间相当。     

基于CCD的高精度水管倾斜仪研制

CCD技术近年来已发展的非常成熟,应用范围广泛.本文介绍了利用CCD技术实现的高精度水管倾斜仪测量系统,其采用非接触式测量方法降低了测量过程中浮子干扰对测量精度的影响,体积小,安装简单,可用于流动观测中.     

库尔勒台水平摆与垂直摆倾斜仪效能对比研究

基于水平摆和垂直摆两种摆式倾斜仪不同的工作原理,对比分析库尔勒台的这两种倾斜仪的观测精度、年变幅、年零漂、稳定性、映震能力,研究观测环境和天气过程等不同影响因素对观测造成的干扰差异性,综合评价水平摆和垂直摆仪器的各项参数和优劣性,同时提取了可识别的前兆异常特征,为数据处理、资料分析、震情跟踪提供科学的依据。     

山东水管倾斜仪观测运行分析

文章介绍了山东地区3个地震台站安装的水管倾斜仪的基本概况,并选取各台2007年—2011年的观测数据,从资料的完整性、观测质量及受干扰情况等方面进行了分析和探讨。结果表明:3个台站的观测资料均有很好的连续性和完整性,仪器稳定性较高,观测系统运转正常,可为地震研究提供数据支持。同时发现,在日常观测中,水管仪地倾斜观测主要受气压、降雨、观测环境变化和仪器调修等因素的干扰。     

库尔勒台DSQ水管倾斜仪和SQ-70石英倾斜仪观测资料对比分析

从DSQ水管倾斜仪、SQ-70石英水平摆倾斜仪的原理出发,结合实际观测,对库尔勒地震台两套倾斜仪器所记录的资料进行对比分析。通过地倾斜的趋势分析及合成矢量分析,表明两套仪器的观测结果是基本一致的,能够较好地反映监测区域大地倾斜的变化特征。两套倾斜仪潮汐分析结果与监测场的局部构造环境是一致的,但水管倾斜仪的观测精度明显高于水平摆倾斜仪。     

钻孔倾斜仪高频实验观测数据的初步分析

利用测震数采器对昌平台CZB钻孔倾斜仪开展了100次/秒的高频采集实验,记录到了可靠的观测资料,其中蕴含的地震信息也更加丰富。同时利用十三陵台测震资料与昌平台钻孔倾斜高频观测资料进行对比分析,结果表明:两种仪器都记录到了地震波响应,但由于频响特性差异,钻孔倾斜仪记录的地震波所对应的P波震相较弱;通过频谱分析估计钻孔倾斜仪的频响偏低频,其频率上限大致在0.1Hz以内;对于一个近地震事件,钻孔倾斜仪的响应表现出与测震仪完全不一样的形态,其低频响应明显优于高频响应;对于远震,随着震中距的增加,两者响应特性逐渐趋于一致。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Information for authors

正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research.     

INTERNATIONAL RESEARCH AND TRAINING CENTER ON EROSION AND SEDIMENTATION(IRTCES)

正Director:Shangfu Kuang,China Vice-directors:Chunhong Hu,China Duihu Ning,China Guangquan Liu,China The International Research and Training Center on Erosion and Sedimentation(IRTCES)was jointly set up by the Government of China and UNESCO on July 21,1984.It aims at the promotion of international exchange of knowledge and cooperation in the studies of erosion and     

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Dynamic process-response model of river channel development

Feedback mechanisms, which operate upstream through drawdown and backwater effects and downstream through sediment discharge are responsible for channel evolution. By combining these mechanisms with channel processes it euables a dynamic process-response model to be developed to simulate the initial evolution of straight gravel-bed channels. When erosion commences on a land surface, sediment entrained in the headwater reach by hydraulic action is selectively transported, deposited and reworked. This produces a damped oscillation between degradation and aggradation as the channel and valley respond to spatial and temporal variations in sediment calibre and hydraulic conditions. The initial cut and fill phases are responsible for valley incision and floodplain development while secondary and subsequent activity can produce river terraces. Eventually sediment entrainment in the headwaters declines as slopes are reduced. Subsequent channel evolution is relatively insignificant because it is dependent on local weathering activity producing material that can be transported on declining slopes. Therefore landforms produced during the initial phase of development, when local weathering was non-limiting, dominate the landscape.