scholarly journals Assessment of continental hydrosphere loading using GNSS measurements

2016 ◽  
Vol 101 (1) ◽  
pp. 36-53 ◽  
Author(s):  
Michał Zygmunt ◽  
Marcin Rajner ◽  
Tomasz Liwosz
Keyword(s):  
Hydrological Model ◽  
Water Volume ◽  
International Gnss Service ◽  
Surface Loading ◽  
Vertical Displacements ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Gnss Measurements ◽  
Gnss Observations ◽  
Vertical Deformations

Abstract Presented paper is dedicated to problems of deformation of the Earth's crust as a response to the surface loading caused by continental waters. The aim of this study was to specify areas particularly vulnerable to studied deformation and to compare calculated and observed displacements. Information of the continental water volume was taken from the WaterGAP Global Hydrological Model. Calculated values of the deformations were verified with the results obtained with programs SPOTL and grat. Vertical deformations were almost 10 times higher than the deformation in the horizontal plane, for which reason later part of the paper focuses on the former. In order to check agreement of the calculated and observed deformation 23 stations of International GNSS Service (IGS) were selected and divided into three groups (inland, near the shoreline and islands). Before comparison outliers and discontinuities were removed from GNSS observations. Modelled and observed signals were centred. The analysed time series of the vertical displacements showed that only for the inland stations it is possible to effectively remove displacements caused by mass transfer in the hydrosphere. For stations located in the coastal regions or islands, it is necessary to consider additional movement effects resulting from indirect ocean tidal loading or atmosphere loading.

The effect of ocean tidal loading on satellite altimetry over Antarctica

2000 ◽  
Vol 12 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Donghui Yi ◽  
J. Bernard Minster ◽  
Charles R. Bentley
Keyword(s):  
Ice Sheet ◽  
Ocean Tide ◽  
Polar Regions ◽  
Laser Altimeter ◽  
Vertical Displacements ◽  
Ocean Loading ◽  
Elevation Changes ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Ocean Tide Models

Vertical displacements of emerged land caused by oceanic tidal loading are of the order of several tens of millimetres in polar regions. They constitute a long wavelength signal, the amplitude of which is comparable to elevation changes that might be associated with climate-driven changes in ice-sheet volume. Using bilinear interpolation on a 1° by 1° global grid, we examine the amplitudes and phases of vertical displacements caused at any given epoch by the eight most important ocean tide constituents of recent ocean tide models, extrapolated to high latitudes. This permits estimation of the oceanic tidal loading corrections to measurements made by a satellite altimeter along the satellite ground track. We have done so systematically over Antarctica, for a scenario flight of ICESAT, which carries the Geoscience Laser Altimeter System (GLAS), whose primary science goal is to monitor ice-sheet mass balance. Ocean loading tide corrections near the coast of Antarctica can reach several centimetres; overall they average about 10 min.

scholarly journals Estimation and Analysis of GNSS Differential Code Biases (DCBs) Using a Multi-Spacing Software Receiver

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 443
Author(s):  
Ye Wang ◽  
Lin Zhao ◽  
Yang Gao
Keyword(s):  
Primary Source ◽  
Intermediate Frequency ◽  
Global Navigation Satellite Systems ◽  
Electron Content ◽  
Software Receiver ◽  
International Gnss Service ◽  
Total Electron ◽  
Satellite Systems ◽  
Differential Code Biases ◽  
Gnss Observations

In the use of global navigation satellite systems (GNSS) to monitor ionosphere variations by estimating total electron content (TEC), differential code biases (DCBs) in GNSS measurements are a primary source of errors. Satellite DCBs are currently estimated and broadcast to users by International GNSS Service (IGS) using a network of GNSS hardware receivers which are inside structure fixed. We propose an approach for satellite DCB estimation using a multi-spacing GNSS software receiver to analyze the influence of the correlator spacing on satellite DCB estimates and estimate satellite DCBs based on different correlator spacing observations from the software receiver. This software receiver-based approach is called multi-spacing DCB (MSDCB) estimation. In the software receiver approach, GNSS observations with different correlator spacings from intermediate frequency datasets can be generated. Since each correlator spacing allows the software receiver to output observations like a local GNSS receiver station, GNSS observations from different correlator spacings constitute a network of GNSS receivers, which makes it possible to use a single software receiver to estimate satellite DCBs. By comparing the MSDCBs to the IGS DCB products, the results show that the proposed correlator spacing flexible software receiver is able to predict satellite DCBs with increased flexibility and cost-effectiveness than the current hardware receiver-based DCB estimation approach.

scholarly journals On the Influence of Diurnal and Subdiurnal Signals in the Normal Vector on Large Ring Laser Gyroscope Observations

2020 ◽  
Vol 177 (9) ◽  
pp. 4217-4228
Author(s):  
Monika Tercjak ◽  
André Gebauer ◽  
Marcin Rajner ◽  
Aleksander Brzeziński ◽  
Karl Ulrich Schreiber
Keyword(s):  
Solid Earth ◽  
Ring Laser ◽  
Earth Tides ◽  
Love Numbers ◽  
Ring Laser Gyroscope ◽  
Solid Earth Tides ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Laser Gyroscope ◽  
The Impact

Abstract The ring laser gyroscope (RLG) technique has been investigated for over 20 years as a potential complement to space geodetic techniques in measuring Earth rotation. However, RLGs are also sensitive to changes in their terrestrial orientation. Therefore in this paper, we review how the high-frequency band (i.e. signals shorter than 0.5 cycle per day) of the known phenomena causing site deformation contribute to the RLG observable, the Sagnac frequency. We study the impact of solid Earth tides, ocean tidal loading and non-tidal loading phenomena (atmospheric pressure loading and continental hydrosphere loading). Also, we evaluate the differences between available models of the phenomena and the importance of the Love numbers used in modeling the impact of solid Earth tides. Finally, we compare modeled variations in the instrument orientation with the ones observed with a tiltmeter. Our results prove that at the present accuracy of the RLG technique, solid Earth tides and ocean tidal loading effects have significant effect on RLG measurements, and continental hydrosphere loading can be actually neglected. Regarding the atmospheric loading model, its application might introduce some undesired signals. We also show that discrepancies arising from the use of different models can be neglected, and there is almost no impact arising from the use of different Love numbers. Finally, we discuss differences between data reduced with tiltmeter observations and these reduced with modeled signal, and potential causes of this discrepancies.

scholarly journals Vertical Displacement due to Ocean Tidal Loading Around Taiwan Based on GPS Observations

2011 ◽  
Vol 22 (4) ◽  
pp. 373 ◽  
Author(s):  
Ta-Kang Yeh ◽  
Cheinway Hwang ◽  
Jiu-Fu Huang ◽  
Benjamin Fong Chao ◽  
Ming-Han Chang
Keyword(s):  
Vertical Displacement ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Gps Observations

scholarly journals Semi-diurnal and diurnal variation of errors in GPS precipitable water vapor at Tsukuba, Japan caused by site displacement due to ocean tidal loading

2000 ◽  
Vol 52 (10) ◽  
pp. 685-690 ◽  
Author(s):  
Yoshinori Shoji ◽  
◽  
Hajime Nakamura ◽  
Kazumasa Aonashi ◽  
Akinori Ichiki ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diurnal Variation ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Ocean Tidal Loading ◽  
Tidal Loading

scholarly journals GNSS and RPAS integration techniques for studying landslide dynamics: Application to the areas of Victoria and Colinas Lojanas, (Loja, Ecuador)

2021 ◽  
Author(s):  
Belizario A. Zárate Torres ◽  
Rachid El Hamdouni ◽  
Tomas Fernández del Castillo
Keyword(s):  
Spatiotemporal Analysis ◽  
Ground Control Points ◽  
Surface Models ◽  
Slow Flows ◽  
Vertical Displacements ◽  
Integration Techniques ◽  
High Resolution Images ◽  
Gnss Measurements ◽  
Gnss Data ◽  
Landslide Dynamics

Abstract. This research tests the application of GNSS and RPAS techniques to the spatiotemporal analysis of landslide dynamics. Our method began by establishing non-permanent GNSS networks on the slope surfaces to perform periodic measurements by differential GNSS. Similarly, RPAS flights were made to acquire high-resolution images, which were oriented and georeferenced using ground control points and structure-from-motion algorithms to obtain digital surface models and orthophotos ultimately. Based on GNSS measurements, the direction and velocity of displacements were accurately calculated, and orthophotos and DSMs were used to calculate horizontal and vertical displacements in a set of significant points throughout the study area, reaching accuracies higher than 0.035 m in the GNSS data and 0.10 m in the RPAS data. These values were within the accuracy required for such studies. Based on the field observations and the results from the photogrammetric studies, the two studied landslides were classified as very slow flows.

scholarly journals The Extraction of Ocean Tidal Loading from ASAR Differential Interferograms

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 632 ◽  
Author(s):  
Wei Peng ◽  
Qijie Wang ◽  
Yunmeng Cao
Keyword(s):  
Synthetic Aperture Radar ◽  
The United States ◽  
Synthetic Aperture ◽  
Tectonic Deformation ◽  
Spatial Characteristics ◽  
Tide Model ◽  
Ocean Tidal Loading ◽  
Tidal Loading ◽  
Mean Square Errors ◽  
Aperture Radar

The spatiotemporal crustal non-tectonic deformation caused by ocean tidal loading (OTL) can reach the centimeters scale in coastal land areas. The temporal variation of the site OTL displacements can be estimated by the global positioning system (GPS) technique, but its spatial variation needs to be further determined. In this paper, in order to analyze the spatial characteristics of the OTL displacements, we propose a multi-scale decomposition method based on signal spatial characteristics to derive the OTL displacements from differential interferometric synthetic aperture radar (D-InSAR) measurements. The method was tested using long-term advanced synthetic aperture radar (ASAR) data and GPS reference site data from the Los Angeles Basin in the United States, and we compared the results with the FES2014b tide model. The experimental results showed that the spatial function of the OTL displacements in an ASAR image can be represented as a higher-order polynomial function, and the spatial trends of the OTL displacements determined by the InSAR and the GPS techniques are basically consistent with the FES2014b tide model. The root-mean-square errors of the differences between the spatial OTL displacements of these two methods and the FES2014b tide model are less than 0.8 mm. The results indicate that the OTL displacement extracted from InSAR data can accurately reflect the spatial characteristics of the OTL effect, which will help to improve the spatial resolution and accuracy of the OTL displacement in coastal areas.

Monitoring of vertical deformations by means high-precision geodetic levelling. Test case: The Arenoso dam (South of Spain)

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Clara de Lacy ◽  
M. Isabel Ramos ◽  
Antonio J. Gil ◽  
Óscar D. Franco ◽  
Antonio M. Herrera ◽  
...  
Keyword(s):  
High Precision ◽  
Test Case ◽  
Control Points ◽  
A Value ◽  
External Shell ◽  
Vertical Displacements ◽  
The One ◽  
Dam Monitoring ◽  
Vertical Deformations ◽  
Block Center

AbstractThe Arenoso reservoir is created by an embankment dam, with central clay core, slates and greywacke shoulders. This kind of engineering structure is subject of deformation due to factors such as changes of water level of the reservoir, seat structure, climate changes, etc. In general, dam monitoring involves measurements both outside (external shell) and inside the structure. A number of control points is established around the area of the dam and the measurements of the displacements of the control points take place at several epochs. In this study high-precision levelling techniques have been used to monitor the vertical deformations. In particular five high-precision levelling profiles were measured in five surveys: February and July 2008, March and July 2013 and August 2014. In this study the design, observations and results are presented. On the one hand the results put in evidence the precision of the observations that are always under 1-mm level. On the other hand these results indicate downstream (southeastward) motion of the thrust block center of the dam probably during the fall and winter. The subsidence reachs here the maximum with a value of −14 cm in 2014 (in respect of February 2008). The displacements observed at the berms of the dam exhibit a similar trend to the displacements observed at the crest but they are significantly smaller, as expected. The accumulative vertical displacements and the settlement index indicate the magnitude of the movements decrease in time, confirming the dam tends to stabilize.

Ocean tidal loading models assessment using 28 months of gravimetric tidal records in Dublin, Ireland

2021 ◽  
Author(s):  
Przemysław Dykowski ◽  
Kamila Karkowska ◽  
Marcin Sękowski ◽  
Paul Kane
Keyword(s):  
International Association ◽  
Sampling Rate ◽  
Remote Access ◽  
Absolute Gravity ◽  
Joint Analysis ◽  
Raspberry Pi ◽  
Ocean Tide ◽  
Loading Effect ◽  
Ocean Tidal Loading ◽  
Tidal Loading

<p>In June of 2018 a project for the establishment of a modern permanent Absolute Gravity Network  on the island of Ireland was initiated by the National Mapping Agency of Ireland, Ordnance Survey Ireland (OSi) with the cooperation of  Institute of Geodesy and Cartography (IGiK), and Land and Property Services (LPS) in Northern Ireland. The project assumes conducting absolute gravity surveys of the network using  the A10 absolute gravimeter on approximately 60 stations homogenously distributed on the island of Ireland.</p><p>Data processing includes time variable corrections for body tides, barometric pressure, polar motion as well as ocean tidal loading. For Ireland the ocean tidal loading effect can reach peaks of between 400 nm/s<sup>2</sup> on the west coast and 200 nm/s<sup>2</sup> on the east coast. This effect is significant and up to now the authors are unaware of previous historical data or  tidal gravity records being performed in Ireland. Hence it was considered as a valid component of the overall Absolute Gravity Project to evaluate the current situation with ocean tidal loading effect in Ireland using gravimetric tidal records in order to validate available ocean tidal loading models.</p><p>In order to assure the most optimal use of ocean tidal model as well as minimize the errors of including ocean tidal correction in absolute gravity processing the LaCoste&Romberg model G spring gravimeter was installed at OSi headquarters in Phoenix Park, Dublin, Ireland. Over a continuous period of 28 months gravity record with more than 99% data completeness at near 2Hz sampling rate was conducted.</p><p>The project data was acquired through using a self-programmed Raspberry Pi computer allowing for automatic download and remote access to the data.</p><p>A set of CSR, DTU, EOT, FES, GOT, TPXO (ocean tide loading provider – Chalmers, http://holt.oso.chalmers.se/loading/) ocean tidal loading models were used in a joint analysis with the collected tidal record. Analysis included performing tidal adjustment of the gravity data in the ETERNA 3.40 (ET34-X-V73) as well as comparison of IAG (International Association of Geodesy) recommended model combinations with the collected data.</p><p>Recommendations by the project team as to which of the ocean tidal models is most suitable to be used in Ireland for the purpose of absolute gravity measurements were made.</p>

Sign in / Sign up

Export Citation Format

Share Document