scholarly journals Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6044
Author(s):  
Krzysztof Pyrchla ◽  
Arkadiusz Tomczak ◽  
Grzegorz Zaniewicz ◽  
Jerzy Pyrchla ◽  
Paulina Kowalska
Keyword(s):  
Data Stream ◽  
Gravity Data ◽  
Gravity Measurement ◽  
Reference Level ◽  
Height Distribution ◽  
Dynamic Height ◽  
Area Of Interest ◽  
Gravimetric Measurements ◽  
Accuracy Of Measurements ◽  
Odra River

This article presents possible applications of a dynamic gravity meter (MGS-6, Micro-g LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.

scholarly journals Measurement of the difference in the geomagnetic induction between the magnetometer pillars of the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station

2021 ◽  
pp. 16-23
Author(s):  
M. Leonov ◽  
◽  
Yu. Otruba ◽  
Keyword(s):  
Geomagnetic Field ◽  
Reference Value ◽  
Fixed Time ◽  
Reference Level ◽  
Geomagnetic Observatory ◽  
Field Induction ◽  
Geomagnetic Induction ◽  
Accuracy Of Measurements ◽  
The Difference ◽  
Mobile Measurements

The article describes the features of measurements of spatial inhomogeneities of the geomagnetic field between the pillars of magnetometers in the measuring pavilion, which were carried out at the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station in 2015. Some preliminary results of these measurements are also given. The concept of the timescaled value of the geomagnetic field induction is introduced, which is convenient for compensating for time changes of the real geomagnetic induction and bringing it to one reference level of induction. The differences in geomagnetic induction between pillars are obtained as the differences in time-scaled values of the geomagnetic induction on the pillars. The technique allows comparing long-term series of measurements of field inhomogeneities at important points in space. The main objectives are to increase the accuracy of measurements of local inhomogeneities of the geomagnetic field in the measuring pavilion of the geomagnetic observatory of the Ukrainian Antarctic Akademik Vernadsky station and to determine the differences in the geomagnetic induction between the pillars on which the magnetometer sensors are installed. Obtaining numerical values of the differences in the geomagnetic induction between the pillars as objective criteria needed to assess the accuracy of the data in the final processing of geomagnetic observatory data. The method of comparison of two series of data is used: one obtained by the scalar magnetometer installed in the observatory as a mandatory stationary device, and the other obtained during measurements with a mobile magnetometer at the desired points in space. Compensation of temporal changes of the geomagnetic field by time-scaling the measurement readings of the mobile magnetometer relative to one reference value and thus, bringing them to one selected and fixed time epoch. Special geometric scheme of mobile measurements in the space around the pillars with magnetometer sensors or at important points in space. A rough estimate of method errors. Based on the analysis of the obtained data, the efficiency of the method and its acceptable potential accuracy were confirmed. We obtained approximate numerical values of the differences in the geomagnetic field induction between the pillars on which the magnetometer sensors are installed. Further increase in the accuracy of determining these differences is possible using modern devices of high accuracy and GPS-synchronization of mobile measurements.

scholarly journals Optimum density determination for bouguer correction using statistical methods: a case study from north of Iran

2015 ◽  
Vol 3 (2) ◽  
pp. 25
Author(s):  
Ata Eshaghzadeh ◽  
Roghayeh sadat Kalantari ◽  
Zohreh Moeini Hekmat
Keyword(s):  
Statistical Methods ◽  
Gravity Data ◽  
High Quality ◽  
Geological Structures ◽  
Optimum Density ◽  
Density Determination ◽  
Area Of Interest ◽  
North Of Iran ◽  
Terrain Corrections

<p>The main aim of initial gravity data processing is to determine the density of under-research geological structures and stratification mat rials in this case. The density is important for the calculation of the Bouguer plate and terrain corrections. To achieve the corrected gravity data with high quality and accuracy, exact estimation of the density is very significant, but representative optimum density value for an area of interest is notoriously difficult to obtain. In this paper, several statistical methods based on the correlation are proposed, such as variation and fractal for surface optimum density determination. The efficiency of the methods has been employed for a case study in north of Iran.</p>

scholarly journals MetOp Satellites Data Processing for Air Pollution Monitoring in Morocco

2018 ◽  
Vol 8 (6) ◽  
pp. 4584 ◽  
Author(s):  
Mohamed Akram Zaytar ◽  
Chaker El Amrani
Keyword(s):  
Machine Learning ◽  
Data Processing ◽  
Data Stream ◽  
Processing System ◽  
Pollution Monitoring ◽  
Continuous Data ◽  
Data Processing System ◽  
Air Pollution Monitoring ◽  
Area Of Interest ◽  
Computational Processes

<p>This paper presents a data processing system based on an architecture comprised of multiple stacked layers of computational processes that transforms Raw Binary Pollution Data coming directly from Two EUMETSAT MetOp satellites to our servers, into ready to interpret and visualise continuous data stream in near real time using techniques varying from task automation, data preprocessing and data analysis to machine learning using feedforward artificial neural networks. The proposed system handles the acquisition, cleaning, processing, normalizing, and predicting of Pollution Data in our area of interest of Morocco.</p>

scholarly journals A global comparison of Argo and satellite altimetry observations

Ocean Science ◽  
2011 ◽  
Vol 7 (2) ◽  
pp. 175-183 ◽  
Author(s):  
A. -L. Dhomps ◽  
S. Guinehut ◽  
P.-Y. Le Traon ◽  
G. Larnicol
Keyword(s):  
Sea Level ◽  
Ocean Circulation ◽  
Global Ocean ◽  
Reference Level ◽  
Argo Data ◽  
Sea Level Variability ◽  
Dynamic Height ◽  
Global Comparison ◽  
Spatial Coverage ◽  
Basin Scale

Abstract. Differences, similarities and complementarities between Sea Level Anomalies (SLA) deduced from altimeter measurements and dynamic height anomalies (DHA) calculated from Argo in situ temperature (T) and salinity (S) profiles are globally analyzed. SLA and DHA agree remarkably well and, compared to previous studies, Argo dataset allows an improvement in the coherence between SLA and DHA. Indeed, Argo data provides a much better spatial coverage of all oceans and particularly the Southern Ocean, the use of an Argo mean dynamic height, the use of measured salinity profiles (versus climatological salinity), and the use of a deeper reference level (1000 m versus 700 m). The large influence of Argo salinity observations on the consistency between altimetry and hydrographic observations is particularly demonstrated with an improvement of 35% (relative to the SLA minus DHA signal) by using measured salinity profiles instead of climatological data. The availability of observations along the Argo float trajectories also provides a means to describe the sea level variability of the global ocean both for the low frequency and the mesoscale part of the circulation. Results indicate that sea level variability is dominated by baroclinic signal at seasonal to inter-annual periods for all latitudes. In the tropics, sea level variability is baroclinic for meso-scale to interannual periods and at high latitudes, sea level variability is barotropic with also deep baroclinic signals (i.e. influence of deep temperature and salinity signals) for intra seasonal and mesoscale periods. These results emphasize the need to separate the different time and space scales in order to improve the merging of the two data sets. The qualitative study of seasonal to interannual SLA minus DHA signals finally reveals signals related to deep ocean circulation variations and basin-scale barotropic signals. Future work is, however, needed to understand the observed differences and relate them to different forcing mechanisms.

scholarly journals High-resolution gravity measurement aboard an autonomous underwater vehicle

Geophysics ◽  
2018 ◽  
Vol 83 (6) ◽  
pp. G119-G135 ◽  
Author(s):  
Takemi Ishihara ◽  
Masanao Shinohara ◽  
Hiromi Fujimoto ◽  
Toshihiko Kanazawa ◽  
Akito Araya ◽  
...  
Keyword(s):  
High Resolution ◽  
Autonomous Underwater Vehicle ◽  
Gravity Data ◽  
Water Pressure ◽  
Bouguer Anomaly ◽  
Underwater Vehicle ◽  
Mineral Deposits ◽  
Gravity Measurement ◽  
Vertical Acceleration ◽  
Constant Depth

We have developed an underwater gravity measurement system that uses an autonomous underwater vehicle (AUV) for exploration of seafloor mineral deposits. An improved air/sea gravimeter mounted on a gimbal mechanism in a pressure capsule 50 cm in diameter was installed in the AUV Urashima. We carried out 11 AUV dives in Sagami Bay as well as in deep-sea mineral deposit areas offshore Japan. The AUV was navigated at a constant speed of 2 knots and at either constant depth or constant altitude above the sea bottom. We obtained high-resolution Bouguer anomaly data through processing of gravity data, water pressure data, and the AUV’s navigational data, including pitch and roll motion. In addition to a vertical acceleration correction using a precise pressure meter with an in situ conversion factor from pressure to depth, three additional corrections were made to the gravimeter data: corrections for the effects of a spatial separation and a time delay between the depth sensor and the gravimeter, and an adjustment to the conversion from pressure increments to depth increments. These new corrections allowed us to obtain high-resolution data in a constant-depth survey of the southern Izena Hole at a depth of approximately 1550 m. The data had a 0.1 mGal rms crossover difference after leveling. This survey revealed two high Bouguer anomaly areas with amplitudes of 1–2 mGal. A model calculation suggested that the anomalies result from the presence of two buried cylindrical high-density mineral deposits. Our data processing method allows the detection of mineral deposits located at or just beneath the seafloor using gravity data collected aboard AUVs. However, further improvements in resolution are desirable, particularly for surveys in areas with rugged topography.

New gravity control in Poland – needs, the concept and the design

2013 ◽  
Vol 62 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Jan Krynski ◽  
Tomasz Olszak ◽  
Marcin Barlik ◽  
Przemyslaw Dykowski
Keyword(s):  
Environmental Changes ◽  
Geodetic Network ◽  
International Standards ◽  
Gravity Measurement ◽  
Reference Level ◽  
Absolute Gravity ◽  
Gravity Gradient ◽  
Base Points ◽  
Vertical Gravity Gradient ◽  
Gravity Measurements

Abstract The existing Polish gravity control (POGK) established in the last few years of 20th century according to the international standards is spanned on 12 absolute gravity stations surveyed with four different types of absolute gravimeters. Relative measurements performed by various groups on nearly 350 points of POGK with the use of LaCoste&Romberg (LCR) gravimeters were linked to those 12 stations. The construction of the network, in particular the limited number of non homogeneously distributed absolute gravity stations with gravity determined with different instruments in different epochs is responsible for systematic errors in g on POGK stations. The estimate of those errors with the use of gravity measurements performed in 2007-2008 is given and their possible sources are discussed. The development of absolute gravity measurement technologies, in particular instruments for precise field absolute gravity measurements, provides an opportunity to establish new type of gravity control consisting of stations surveyed with absolute gravimeters. New gravity control planned to be established in 2012-2014 will consist of 28 fundamental points (surveyed with the FG5 - gravimeter), and 169 base points (surveyed with the A10 gravimeter). It will fulfill recent requirements of geodesy and geodynamics and it will provide good link to the existing POGK. A number of stations of the new gravity control with precisely determined position and height will form the national combined geodetic network. Methodology and measurement schemes for both absolute gravimeters as well as the technology for vertical gravity gradient determinations in the new gravity control were developed and tested. The way to assure proper gravity reference level with relation to ICAG and ECAG campaigns as well as local absolute gravimeter comparisons are described highlighting the role of metrology in the project. Integral part of the project are proposals of re-computation of old gravity data and their transformation to a new system (as 2nd order network) as well as a definition of gravity system as “zero-tide” system. Seasonal variability of gravity has been discussed indicating that the effects of environmental changes when establishing modern gravity control with absolute gravity survey cannot be totally neglected.

scholarly journals Determination of Vertical Deflection Based on Terestrial Gravity Disturbance Data (A Case Study in Semarang City)

2019 ◽  
Author(s):  
L M Sabri ◽  
Bambang Sudarsono ◽  
Rina Dwi Indriana
Keyword(s):  
Gravity Anomaly ◽  
Gravity Data ◽  
Satellite System ◽  
Gravity Measurement ◽  
Gravity Disturbance ◽  
Vertical Deflection ◽  
Level Measurement ◽  
Vening Meinesz ◽  
Global Navigation Satellite ◽  
New Formula

Vertical deflection can be determined by geometrical and physical measurement. In geometrical way, vertical deflection is obtained by comparing astronomical coordinate and geodetical coordinate. In physical way, vertical deflection can be computed from gravity measurement. In the past, vertical deflection was computed from gravity anomaly data. Gravity anomaly data measurement is difficult because it need reduction of gravity from surface of the earth to the geoid using orthometric height from spirit level measurement. In modern era, gravity anomaly data may be replaced by gravity disturbance data whose only required gravity and GNSS (Global Navigation Satellite System) measurement. This research aims to determine vertical deflection in Semarang City from terrestrial gravity disturbance data. The gravity data were measured in March of 2016. Formula of Vening Meinesz that usually used for vertical deflection was replaced by new formula that generated from derivation of function of Hotine. Applying gravity disturbance gave vertical deflection of east-west component that were vary from -1.2” to 12.2” while north-south component were vary from -4.2” to 4.2”. Comparing vertical deflection as computed from terrestrial data to as computed from EGM2008 coefficients showed conformity in shape and values. It was concluded that derivation of function of Hotine could be applied for vertical deflection determination from gravity disturbance.

scholarly journals Combination of Terrestrial and Satellite Gravity Data for the Characterization of the Southwestern Coastal Region of Cameroon: Appraisal for Hydrocarbon Exploration

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Paul Gautier Kamto ◽  
Willy Lemotio ◽  
Alain-Pierre Kamga Tokam ◽  
Loudi Yap
Keyword(s):  
Gravity Data ◽  
Bouguer Anomaly ◽  
Coastal Region ◽  
Hydrocarbon Exploration ◽  
Horizontal Gradient ◽  
Target Area ◽  
Satellite Gravity ◽  
Area Of Interest ◽  
Anomaly Map ◽  
Bouguer Anomaly Map

The southwestern coastal region of Cameroon is an area of interest because of its hydrocarbon potential (gas and oil). Terrestrial and satellite gravity data were combined and analyzed to provide a better precision in determining the structure of the study area. Firstly, the two gravity databases (in situ and satellite) have been coupled and validated using the least square collocation technique. Then, spectral analysis was applied to the combined Bouguer anomaly map to evaluate the thickness of sediments in some localities. We found that the sedimentary cover of the southwestern coastal region of Cameroon has a thickness that varies laterally from 1.68 ± 0.08 to 2.95 ± 0.15   km , especially in the western part. This result confirms that our target area is a potential site for hydrocarbon exploration. The horizontal gradient method coupled with the upward continuation at variable heights has been used to highlight several lineaments and their directions (N-S, E-W, SW-NE, and SSW-NNE). Lineaments trending in an N-S orientation are predominant. The Euler deconvolution method was also applied to the Bouguer anomaly map to determine the position, orientation, and depth of the different superficial faults of the study area. It appears that the majority of superficial faults have an N-S and SSW-NNE orientation. These directions are correlated with those previously highlighted by the maxima of horizontal gradient. The structural map could be used for a better identification of the direction of fluid flow within the subsurface or to update the geological map of our study area.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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