水位观测仪器的选择与应用

水位是江，河，湖，海水势变化的标志，水位观测是水文测验中最基本的项目之一，而水位观测仪器的质量，性能直接关系到水文资料的收集及其成果质量，因此，选择水位观测仪器至关重要，它直接关系到资料收集的连续性和成果质量的可靠性，对于实现水文技术现代化有着十分重要的意义，本文对长江口区各潮位站自记水位计的工作原理，可靠性，资料精度进行了分析评价，在此基础上，提出选用水位观测仪器的参考意见。     

SSA1—1型声学水位计在三峡陡山沱水位站的比测试验

本文报道ＳＳＡ１－１型声学水位计在长江三峡陡山沱水位站所作的比测试结果，介绍了比测资料的处理及由此得出的初步结论，结果，表明，该仪器所测得的水位过程曲线与上、下游站的水位过程曲线相关性良好，证明了该仪器测量水位的可靠性。     

SCA6－1型声学水位计的声波导设计方法

本文推导了圆柱形声波导管的上限条件和下限条件，给出了ＳＣＡ６－１型声学水位计声波导管的设计方法和设计结果。     

导波式雷达水位计在潮位观测中的应用

文中简要介绍了雷达水位计的测量原理、分类和技术特点,并将其中的导波式雷达水位计和非接触式雷达水位计与传统的浮子式水位计进行了比较,说明了导波式雷达水位计应用于一些特定条件下潮位观测的优势。基于导波式雷达水位计设计了一套水位观测系统。简要介绍了该水位观测系统的系统组成、硬件设计、软件设计。针对该水位观测系统进行了计量检定,并进行了现场安装试验。在现场实验中将导波式雷达水位计数据与浮子式水位计数据进行比较,说明了采用该设计方案进行潮位观测的可行性。     

SCA6—1型声学水位计的声波导设计方法

本文推导了圆柱形声波导管的上限条件和下限条件，给出了ＳＣＡ６－１型声学水位计声波导管的设计方法和设计结果。     

基于图像识别与远程校准的潮位观测系统设计

为了解决浮子式水位计（以下简称浮子水位计）由工作人员定时到潮位观测场校准的工作问题,提高校准准确度,设计了基于图像识别与远程校准的潮位观测系统。该系统依靠在潮位观测场搭载摄像机拍摄目标,采集井内水尺图像,并通过4G、5G通讯将井内水尺视频图像和浮子水位计观测的数据传输至数据中心。数据中心管理软件通过对水尺图片进行图像识别获取井内水尺读数,对井内水尺数据和浮子水位计观测的潮位数据进行对比分析,计算系统不确定度、随机不确定度、综合不确定度,当综合不确定度大于规范误差时,系统不确定度作为漂移量发送给浮子水位计,实现浮子水位计的远程自动校准。经示范应用验证,系统功能性能指标满足业务化运行需求。     

SCA6—1型声学水位计应用研究

本文介绍ＳＣＡ６－１型声学水位计的测量原理与关于仪器安装方法所引起的水位测量误差的研究，并简述了外保护管井的设计及使用中应注意的问题。     

水尺与压力式水位计数据关系的算法研究

针对海道测量中在同一验潮点人工水尺与压力式水位计同步水位观测所得不同的潮位数据,分别绘制潮位曲线,从两条相关的曲线数据中应用三次样条和拟合数学函数模型,利用计算机程序确定曲线间的线性关系,从而根据压力式水位计测得的数据确定的关系得出真实的潮位数据。     

SCA6—1型声学水位计可靠性设计与预计

本文就ＳＣＡ６－１型声学水位计的可靠性设计与预测做了研究和计算,得出了可靠性指标和可靠性保障技术。这是对产品质量要求必不可少的。本文所使用的方法可为其它产品所借鉴     

长江口潮位变化规律及其工程应用

长江口北槽航道水深较浅,为提高航道与疏浚的经济效益,本文研究了航道维护疏浚、测量工程中关键的潮位变化规律,及其在工程上应用的关系。按浅水潮波理论与长江口区11个测站1年的典型潮及地形资料,详细分析了全区潮波运动的一般周期性变化规律,随时、空的非线性演变规律,物理机制及其对各地点潮位变化的制约。结果解释了重要的水文物理现象,提出了确定控制水位的新方法等,为工程需要提供了依据。     

SZS3-1型压力式波潮仪

SZS3—1型压力式波潮仪是“九五”国家863计划的海洋监测技术主题资助的研究成果。介绍了该波潮仪的测量原理、特点、测试、试验及应用情况。     

Absolute Calibration of the Jason-1 Altimeter Using UK Tide Gauges

This article describes an “absolute” calibration of Jason-1 (J-1) altimeter sea surface height bias using a method developed for TOPEX/Poseidon (T/P) bias determination reported previously. The method makes use of U.K. tide gauges equipped with Global Positioning System (GPS) receivers to measure sea surface heights at the same time, and in the same geocentric reference frame, as Jason-1 altimetric heights recorded in the nearby ocean. The main time-dependent components of the observed altimeter-minus-gauge height-difference time series are due to the slightly different ocean tides at the gauge and in the ocean. The main harmonic coefficients of the tide differences are calculated from analysis of the copious TOPEX data set and then applied to the determination of T, P, and J-1 bias in turn. Datum connections between the tide gauge and altimetric sea surface heights are made by means of precise, local geoid differences from the EGG97 model. By these means, we have estimated Jason-1 altimeter bias determined from Geophysical Data Record (GDR) data for cycles 1–61 to be 12.9 cm, with an accuracy estimated to be approximately 3 cm on the basis of our earlier work. This J-1 bias value is in close agreement with those determined by other groups, which provides a further confirmation of the validity of our method and of its potential for application in other parts of the world where suitable tide gauge, GPS, and geoid information exist.     

Absolute Calibration of the Jason-1 Altimeter Using UK Tide Gauges

This article describes an “absolute” calibration of Jason-1 (J-1) altimeter sea surface height bias using a method developed for TOPEX/Poseidon (T/P) bias determination reported previously. The method makes use of U.K. tide gauges equipped with Global Positioning System (GPS) receivers to measure sea surface heights at the same time, and in the same geocentric reference frame, as Jason-1 altimetric heights recorded in the nearby ocean. The main time-dependent components of the observed altimeter-minus-gauge height-difference time series are due to the slightly different ocean tides at the gauge and in the ocean. The main harmonic coefficients of the tide differences are calculated from analysis of the copious TOPEX data set and then applied to the determination of T, P, and J-1 bias in turn. Datum connections between the tide gauge and altimetric sea surface heights are made by means of precise, local geoid differences from the EGG97 model. By these means, we have estimated Jason-1 altimeter bias determined from Geophysical Data Record (GDR) data for cycles 1-61 to be 12.9 cm, with an accuracy estimated to be approximately 3 cm on the basis of our earlier work. This J-1 bias value is in close agreement with those determined by other groups, which provides a further confirmation of the validity of our method and of its potential for application in other parts of the world where suitable tide gauge, GPS, and geoid information exist.     

TOPEX/Poseidon and Jason-1: Absolute Calibration in Bass Strait, Australia

Updated absolute calibration results from Bass Strait, Australia, are presented for the TOPEX/Poseidon (T/P) and Jason-1 altimeter missions. Data from an oceanographic mooring array and coastal tide gauge have been used in addition to the previously described episodic GPS buoy deployments. The results represent a significant improvement in absolute bias estimates for the Bass Strait site. The extended methodology has allowed comparison between the altimeter and in situ data on a cycle-by-cycle basis over the duration of the dedicated calibration phase (formation flight period) of the Jason-1 mission. In addition, it has allowed absolute bias results to be extended to include all cycles since the T/P launch, and all Jason-1 data up to cycle 60. Updated estimates and formal 1-sigma uncertainties of the absolute bias computed throughout the formation flight period are 0 ± 14 mm for T/P and +152 + 13 mm for Jason-1 (for the GDR POE orbits). When JPL GPS orbits are used for cycles 1 to 60, the Jason-1 bias estimate is 131 mm, virtually identical to the NASA estimate from the Harvest Platform off California calculated with the GPS orbits and not significantly different to the CNES estimate from Corsica. The inference of geographically correlated errors in the GDR POE orbits (estimated to be approximately 17 mm at Bass Strait) highlights the importance of maintaining globally distributed verification sites and makes it clear that further work is required to improve our understanding of the Jason-1 instrument and algorithm behavior.     

关于提高SSA_2-1型便携式潮位仪精度的研究

SSA_z-1型便携式潮位仪是以计算机控制晶体压力传感器作为水下探头的无井验潮仪,因为探头是放于水下,因此大气压力、水温、盐度、重力加速度、波浪、涌潮、海流等因素的变化都会给潮位测量带来误差,本文论述了上述诸因素给潮位测量带来的影响及提高 SSA_z-1潮位仪精度的措施.     

GNSS-Based Sea Level Monitoring

This paper attempts to assess the use of Global Navigation Satellite System (GNSS) as an accurate, reliable, and easy tool for sea level measurement. The GNSS technique was incorporated into a float based tide gauge system. A prototype of such an instrument was developed based on principles of conventional tide gauges, where high frequency noise is reduced mechanically. The ability of the GNSS based tide gauge (GTG) to monitor sea levels was tested in several experiments. The performance of the GTG was compared to that of a traditional tide gauge. The method of data analysis and data comparison between the GPS measurements and the tide gauge data is presented. The results show that the GTG is equal in performance to the traditional float operated tide gauge. It seems that the GTG is capable of delivering the same level of accuracy (1 cm), and its results are as reliable as its competitor, the traditional float tide gauge. The suggested instrument can be easily integrated into the array of permanent GNSS stations and assist in absolute measurements of sea level changes, caused by global warming and the greenhouse effect, for example.     

GNSS-Based Sea Level Monitoring

This paper attempts to assess the use of Global Navigation Satellite System (GNSS) as an accurate, reliable, and easy tool for sea level measurement. The GNSS technique was incorporated into a float based tide gauge system. A prototype of such an instrument was developed based on principles of conventional tide gauges, where high frequency noise is reduced mechanically. The ability of the GNSS based tide gauge (GTG) to monitor sea levels was tested in several experiments. The performance of the GTG was compared to that of a traditional tide gauge. The method of data analysis and data comparison between the GPS measurements and the tide gauge data is presented. The results show that the GTG is equal in performance to the traditional float operated tide gauge. It seems that the GTG is capable of delivering the same level of accuracy (1 cm), and its results are as reliable as its competitor, the traditional float tide gauge. The suggested instrument can be easily integrated into the array of permanent GNSS stations and assist in absolute measurements of sea level changes, caused by global warming and the greenhouse effect, for example.     

Combined Sea Surface Determination Based on Various Geometric and Dynamic Techniques

Abstract

The combined use of Global Positioning System (GPS) differential positioning as well as ERS‐1 altimeter data is considered in implementing geodetic vertical datums and their unification. The article describes concepts, techniques, practical realization, and associated questions and problems. Particular aspects in view of small sea surface perturbations in offshore areas in determining sea surface components (variable and steady state) are discussed. The combinations of tide gauge data with altimetry and (mainly) GPS positioning for geodetic purposes are discussed in detail. Special attention is devoted to the associated reference systems as well as to the combination of dynamic (level and nonlevel surfaces) with geometric quantities. The discussion is based on a specific ERS‐1 project supported by the National Science Foundation. Implications and practical impact of the project are outlined.     

双通道声学水位计

双通道声学水位计是在 SSA1- 1型声学水位计的基础上 ,通过一台主机带两个探头 ,进行准同步测量而实现的