共查询到20条相似文献，搜索用时 78 毫秒
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我国的海洋活动逐步向远海开展,对海洋观测技术提出了新的要求。基于GNSS的动态后处理差分测量技术,提出了一种新型远距离验潮系统。建立了基于PC104总线的模块化潮汐测量系统硬件,基于LabVIEW语言开发了与验潮系统硬件相匹配的软件,实现了潮汐测量过程中数据采集、数据处理和设备监控等功能。将该系统安装于国内某大型海洋浮标,在离岸约200km的海域开展了潮汐测量实验,通过GNSS数据解算、高程修正、滤波和潮位提取等数据处理步骤得到潮位数据。将系统测量的潮位结果与经典潮汐模型的潮位模拟数据相比,发现二者具有良好的一致性,整体潮位测量精度为4.6cm。 相似文献
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青岛验潮站位于青岛大港一号码头西端 ,是我国长期基本验潮站。该站 190 0年开始进行潮汐观测 ,190 4年建立验潮井 ,用浮筒式自记验潮仪进行观测 ;19 38～ 1945年 ,日本第二次占领青岛时期 ,验潮井遭到破坏 ,1948年验潮井修复并恢复观测。民国时期 ,验潮站用压力式验潮仪工作。新中国成立以来 ,海洋观测工作不断得到加强。 1996年 ,重新修建了验潮井和工作房 ,安装了新型水位计。目前 ,该站拥有 2台瓦尔代验潮仪 ,一台NGWL MS新一代水位计和一台 SCA6 - 1型声学水位计分别进行同步观测比对 ,资料准确可靠。195 4年 ,统一测量全国海洋基… 相似文献
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在海洋测深中，由于波浪和潮汐的影响，调查船或无人船所测量的瞬时水深不能直接作为海图水深。本文提出了一种新型的无人船海洋水深测量技术，以评估搭载RTK和单波束测深仪的无人船用于海洋水深测量的潜能。首先，使用无人船所搭载RTK的厘米级精度高程数据，通过低通滤波剔除波浪信息，而获得海平面高程。然后，基于潮汐表和无人船海平面高程，构建了一种参考椭球面和海图的两个基准面之差的获取方法；在常规的海洋调查中，该基准面差通常需要由长期的验潮获得。最后，利用海图基准和无人船测量的瞬时水深的转换关系，计算出海图水深。在海南省蜈支洲岛周边海域，利用自研发的无人船“USBV”开展了相关海上实验，以验证所提出的技术方法。实验结果验证了该无人船海洋水深测量技术。 相似文献
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GPS验潮中波浪的误差分析和消除 总被引：8，自引：0，他引：8
GPS验潮采用GPS RTK计算潮位，是目前GPS技术发展和应用的一个方向，对验潮方法的革新和GPS的进一步应用有着重要的意义。在水面上，波浪引起载体的空间位置改变，给验潮带来很大的误差。为了得到厘米级精度的潮位，必须消除波浪的影响。详细分析了GPS测姿方法和姿态补偿，最后采用小波去噪提取出了潮汐信号。实测数据和模拟数据证明GPS验潮可达到厘米级的精度，满足常规水深测量的精度要求。 相似文献
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The UK Hydrographic Office (UKHO)-sponsored Vertical Offshore Reference Frames (VORF) project aims to develop tidal level transformation models that are referenced to the GRS80 ellipsoid and thus compatible with GNSS positioning; in particular, heighting. Benefits include increasing the efficiency of hydrographic surveying, providing a stable consistent reference frame and enabling integration with land data in the coastal zone. Seven contemporary global ocean tide models are used to derive Lowest Astronomical Tide (LAT) surfaces which are each assessed by comparison with LAT values from the 7,389-strong UKHO tide gauge database, with the results correlated with distance from land. The proportion of truly offshore and pelagic gauges is relatively limited; however, the transition zone whereby the global ocean tide models commence to deteriorate in accuracy is evident at approximately 30km from the coast. The DTU10 model was selected as the strongest candidate overall. Subsequently, a thin plate spline method is used with the tide gauge dataset to enhance the DTU10 LAT surface in the coastal zone, creating a high resolution global LAT surface with respect to mean sea level. It is seen by cross-validation that the method may be used to predict LAT in near-shore locations with a standard error of 0.23 m. 相似文献
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Ole Baltazar Andersen Karina Nielsen Per Knudsen Chris W. Hughes Rory Bingham Luciana Fenoglio-Marc 《Marine Geodesy》2013,36(6):517-545
AbstractThe ocean mean dynamic topography (MDT) is the surface representation of the ocean circulation. The MDT may be determined by the ocean approach, which involves temporal averaging of numerical ocean circulation model information, or by the geodetic approach, wherein the MDT is derived using the ellipsoidal height of the mean sea surface (MSS), or mean sea level (MSL) minus the geoid as the geoid. The ellipsoidal height of the MSS might be estimated either by satellite or coastal tide gauges by connecting the tide gauge datum to the Earth-centred reference frame. In this article we present a novel approach to improve the coastal MDT, where the solution is based on both satellite altimetry and tide gauge data using new set of 302 tide gauges with ellipsoidal heights through the SONEL network. The approach was evaluated for the Northeast Atlantic coast where a dense network of GNSS-surveyed tide gauges is available. The typical misfit between tide gauge and satellite or oceanographic MDT was found to be around 9?cm. This misfit was found to be mainly due to small scale geoid errors. Similarly, we found, that a single tide gauge places only weak constraints on the coastal dynamic topography. 相似文献
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R. K. Nayak M. Salim S. K. Sasamal P. C. Mohanthy R. K. Bharadwaj K. H. Rao 《Marine Geodesy》2016,39(5):331-347
The present tidal correction of sea level records of Satellite with ARgoes and ALtimeter (SARAL) is based on the finite element solution (FES) of global tide model FES2012 tidal solution. In this study, we examined the validity of the tidal corrections in the coastal oceans around India using tide gauge measurements and a regional tidal model. Our regional model is based on the barotropic version of the Princeton Ocean Model that is forced by the time-varying tidal levels at the open ocean end based on the global FES99 tidal solution. Tide charts prepared from the simulated tidal levels are very similar to the FES tidal solutions. Comparison with the tide gauge measurement shows close agreement with the regional tidal solutions. On the other hand, the agreement with the FES tide models differ significantly in the Gulf of Khambhat and the Gulf of Kutch on the northwest, and in the Hooghly estuary on the northeast continental shelf. However, the agreement is exceptional in other parts of the study domain. These tidal solutions are used in the SARAL-ALTIKA X-track data to assess the FES tidal correction and to draw some inferences associated with the coastal processes. It is revealed that these corrections are reasonably accurate for the coastal oceans around India except the aforementioned converging channels. 相似文献
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Tide gauges distributed all over the world provide valuable information for monitoring mean sea level changes. The statistical models used in estimating sea level change from the tide gauge data assume implicitly that the random model components are stationary in variance. We show that for a large number of global tide gauge data this is not the case for the seasonal part using a variate-differencing algorithm. This finding is important for assessing the reliability of the present estimates of mean sea level changes because nonstationarity of the data may have marked impact on the sea level rate estimates, especially, for the data from short records. 相似文献
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Tide gauges distributed all over the world provide valuable information for monitoring mean sea level changes. The statistical models used in estimating sea level change from the tide gauge data assume implicitly that the random model components are stationary in variance. We show that for a large number of global tide gauge data this is not the case for the seasonal part using a variate-differencing algorithm. This finding is important for assessing the reliability of the present estimates of mean sea level changes because nonstationarity of the data may have marked impact on the sea level rate estimates, especially, for the data from short records. 相似文献
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Ocean Tide Models Developed by Assimilating TOPEX/POSEIDON Altimeter Data into Hydrodynamical Model: A Global Model and a Regional Model around Japan 总被引：36，自引：0，他引：36
A global ocean tide model (NAO.99b model) representing major 16 constituents with a spatial resolution of 0.5° has been estimated by assimilating about 5 years of TOPEX/POSEIDON altimeter data into barotropic hydrodynamical model. The new solution is characterized by reduced errors in shallow waters compared to the other two models recently developed; CSR4.0 model (improved version of Eanes and Bettadpur, 1994) and GOT99.2b model (Ray, 1999), which are demonstrated in comparison with tide gauge data and collinear residual reduction test. This property mainly benefits from fine-scale along-track tidal analysis of TOPEX/POSEIDON data. A high-resolution (1/12°) regional ocean tide model around Japan (NAO.99Jb model) by assimilating both TOPEX/POSEIDON data and 219 coastal tide gauge data is also developed. A comparison with 80 independent coastal tide gauge data shows the better performance of NAO.99Jb model in the coastal region compared with the other global models. Tidal dissipation around Japan has been investigated for M2 and K1 constituents by using NAO.99Jb model. The result suggests that the tidal energy is mainly dissipated by bottom friction in localized area in shallow seas; the M2 ocean tidal energy is mainly dissipated in the Yellow Sea and the East China Sea at the mean rate of 155 GW, while the K1 energy is mainly dissipated in the Sea of Okhotsk at the mean rate of 89 GW. TOPEX/POSEIDON data, however, detects broadly distributed surface manifestation of M2 internal tide, which observationally suggests that the tidal energy is also dissipated by the energy conversion into baroclinic tide. 相似文献
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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. 相似文献
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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. 相似文献
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利用水文气象要素因子的变化趋势预测南海区赤潮的发生 总被引：7，自引：2，他引：7
有关文献指出:“赤潮发生起因因种而异……,但大体上气候气象条件诸如温度、风力、风向,季风转换、气-压等;海况、潮汐、流等以及海水的理化特征,如盐度、营养元素等,这些皆会成为某种赤潮爆发的因子或诱导因素”。根据赤潮监控区监测资料分析: 在南海赤潮多发区,海水富营养化条件已经具备,因此气象、水文要素条件就成为赤潮爆发的重要启动因子,而大气环流的维持与变化决定了气象、水文要素因子的稳定与变化,然而根据赤潮生物培养试验,从初期繁殖到后期的爆发性繁殖,直至达到赤潮生物密度,这一过程一般都需要4-5d的时间。针对这一现象,通过对近10a的赤潮发生个例进行统计分析,统计其生成前期的大气环流形势和水文气象要素,分析出赤潮生成前期的环流模式和筛选出诱发赤潮爆发的重要因子,并以此来作为预报赤潮生成的方法。依照此方法对2003年的赤潮进行预报,其效果是令人满意的。 相似文献