scholarly journals Evaluation of the Accuracy of Bathymetry on the Nearshore Coastlines of Western Korea from Satellite Altimetry, Multi-Beam, and Airborne Bathymetric LiDAR

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2926 ◽  
Author(s):  
Yeon Yeu ◽  
Jurng-Jae Yee ◽  
Hong Yun ◽  
Kwang Kim
Keyword(s):  
Disaster Preparedness ◽  
Satellite Altimetry ◽  
Gravity Anomalies ◽  
Side Scan Sonar ◽  
Single Beam ◽  
Bathymetric Data ◽  
Depth Data ◽  
Sonar Sensors ◽  
Beam Depth ◽  
Territory Management

Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and side-scan sonar sensors. Procuring bathymetric data near coastlines using shipborne sensors is difficult, however, this type of data is important for maritime safety, marine territory management, climate change monitoring, and disaster preparedness. In recent years, the bathymetric light detection and ranging (LiDAR) technique has been tried to get seamless geospatial data from land to submarine topography. This paper evaluated the accuracy of bathymetry generated near coastlines from satellite altimetry-derived gravity anomalies and multi-beam bathymetry using a tuning density contrast of 5000 kg/m3 determined by the gravity-geologic method. Comparing with the predicted bathymetry of using only multi-beam depth data, 78% root mean square error from both multi-beam and airborne bathymetric LiDAR was improved in shallow waters of nearshore coastlines of the western Korea. As a result, the satellite-derived bathymetry estimated from the multi-beam and the airborne bathymetric LiDAR was enhanced to the accuracy of about 0.2 m.

scholarly journals BATHYMETRIC SURVEYING IN LAKE SUPERIOR: 3D MODELING AND SONAR EQUIPMENTS COMPARING

2019 ◽  
Vol XLII-2/W10 ◽  
pp. 101-106
Author(s):  
E. Levin ◽  
G. Meadows ◽  
R. Shults ◽  
U. Karacelebi ◽  
H. S. Kulunk
Keyword(s):  
Data Acquisition ◽  
Coordinate System ◽  
Autonomous Underwater Vehicle ◽  
3D Models ◽  
Data Sets ◽  
Side Scan Sonar ◽  
Single Beam ◽  
Bathymetric Data ◽  
Sonar Systems ◽  
Elevation Changes

<p><strong>Abstract.</strong> This paper represents the overview of hydrographic surveying and different types of modern and traditional surveying equipment, and data acquisition using the traditional single beam sonar system and a modern fully autonomous underwater vehicle (AUV) IVER3. During the study, the data sets were collected using the vehicles of the Great Lake Research Center at Michigan Technological University. This paper presents how to process and edit the bathymetric data on SonarWiz5. Lastly, it compares the accuracy of the two different sonar systems in the different missions and creates 3D models to display and understand the elevations changes. Moreover, the 3D models were created after importing the data sets in the same coordinate system. In this study, the data sets were recorded by two different sensors in the two study locations in the Keweenaw Waterway in Michigan, U.S. between the cities of Houghton and Hancock. The first one equipment is the Lowrance HDS-7 sonar on the surveying boat, and other one is the EdgeTech 2205 sonar on the fully AUV of IVER3. One of the purposes of this study is to explore the sonar post processing programs, which are very important to interpret sonar and bathymetric data, and obtained the same coordinate system of the study areas. During the project, three main processing programs were used. The first one is UnderSee Explorer 2.6, which has been used to process the data sets of Polar SV boat. Secondly, EdgeTech Discover 4600 bathymetric software used EdgeTech 2205 sonar data sets to create bathymetric files that were used in SonarWiz5. Lastly, SonarWiz5 sonar processing software can be used to process the data sets. After the data acquisition and the data process, six profiles from the first study area and the five profiles from the second study are created to compare the data sets and elevations difference. It is shown that single beam sonar might miss some details, such as pipeline and quick elevation changes on seabed when we compare to the side scan sonar of IVER3 because the single side scan sonar can acquire better resolutions to understand the 3D features, such as pipelines, reliefs etc.</p>

Contribution of satellite altimetry in modelling Moho density contrast in oceanic areas

2019 ◽  
Vol 13 (1) ◽  
pp. 33-40 ◽  
Author(s):  
M. Abrehdary ◽  
L. E. Sjöberg ◽  
D. Sampietro
Keyword(s):  
Satellite Altimetry ◽  
Density Contrast ◽  
Contrast Model ◽  
Bathymetric Data ◽  
Crustal Model ◽  
Marine Gravity ◽  
Study Results ◽  
Vening Meinesz ◽  
Satellite Altimetry Data

Abstract The determination of the oceanic Moho (or crust-mantle) density contrast derived from seismic acquisitions suffers from severe lack of data in large parts of the oceans, where have not yet been sufficiently covered by such data. In order to overcome this limitation, gravitational field models obtained by means of satellite altimetry missions can be proficiently exploited, as they provide global uniform information with a sufficient accuracy and resolution for such a task. In this article, we estimate a new Moho density contrast model named MDC2018, using the marine gravity field from satellite altimetry in combination with a seismic-based crustal model and Earth’s topographic/bathymetric data. The solution is based on the theory leading to Vening Meinesz-Moritz’s isostatic model. The study results in a high-accuracy Moho density contrast model with a resolution of 1° × 1° in oceanic areas. The numerical investigations show that the estimated density contrast ranges from 14.2 to 599.7 kg/m3 with a global average of 293 kg/m3. In order to evaluate the accuracy of the MDC2018 model, the result was compared with some published global models, revealing that our altimetric model is able to image rather reliable information in most of the oceanic areas. However, the differences between this model and the published results are most notable along the coastal and polar zones, which are most likely due to that the quality and coverage of the satellite altimetry data are worsened in these regions.

scholarly journals Evaluation of Marine Gravity Anomaly Calculation Accuracy by Multi-Source Satellite Altimetry Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Shanwei Liu ◽  
Yinlong Li ◽  
Qinting Sun ◽  
Jianhua Wan ◽  
Yue Jiao ◽  
...  
Keyword(s):  
Root Mean Square Error ◽  
Gravity Anomaly ◽  
Mean Square Error ◽  
Spatial Resolution ◽  
Satellite Altimetry ◽  
Gravity Anomalies ◽  
Mean Square ◽  
Altimetry Data ◽  
Marine Gravity ◽  
Satellite Altimetry Data

The purpose of this paper is to analyze the influence of satellite altimetry data accuracy on the marine gravity anomaly accuracy. The data of 12 altimetry satellites in the research area (5°N–23°N, 105°E–118°E) were selected. These data were classified into three groups: A, B, and C, according to the track density, the accuracy of the altimetry satellites, and the differences of self-crossover. Group A contains CryoSat-2, group B includes Geosat, ERS-1, ERS-2, and Envisat, and group C comprises T/P, Jason-1/2/3, HY-2A, SARAL, and Sentinel-3A. In Experiment I, the 5′×5′ marine gravity anomalies were obtained based on the data of groups A, B, and C, respectively. Compared with the shipborne gravity data, the root mean square error (RMSE) of groups A, B, and C was 4.59 mGal, 4.61 mGal, and 4.51 mGal, respectively. The results show that high-precision satellite altimetry data can improve the calculation accuracy of gravity anomaly, and the single satellite CryoSat-2 enables achieving the same effect of multi-satellite joint processing. In Experiment II, the 2′×2′ marine gravity anomalies were acquired based on the data of groups A, A + B, and A + C, respectively. The root mean square error of the above three groups was, respectively, 4.29 mGal, 4.30 mGal, and 4.21 mGal, and the outcomes show that when the spatial resolution is satisfied, adding redundant low-precision altimetry data will add pressure to the calculation of marine gravity anomalies and will not improve the accuracy. An effective combination of multi-satellite data can improve the accuracy and spatial resolution of the marine gravity anomaly inversion.

The gravity field over the Ungava Bay region from satellite altimetry and new land-based data: implications for the geology of the area

1999 ◽  
Vol 36 (1) ◽  
pp. 75-89 ◽  
Author(s):  
Hamid Telmat ◽  
Jean-Claude Mareschal ◽  
Clément Gariépy
Keyword(s):  
Satellite Altimetry ◽  
Gravity Data ◽  
Gravity Anomalies ◽  
Gravity Models ◽  
Crustal Thickening ◽  
Seismic Line ◽  
Crustal Thinning ◽  
Gravity Measurements ◽  
George River ◽  
Superior Craton

Gravity data were obtained along two transects on the southern coast of Ungava Bay, which provide continuous gravity coverage between Leaf Bay and George River. The transects and the derived gravity profiles extend from the Superior craton to the Rae Province across the New Quebec Orogen (NQO). Interpretation of the transect along the southwestern coast of Ungava Bay suggests crustal thickening beneath the NQO and crustal thinning beneath the Kuujjuaq Terrane, east of the NQO. Two alternative interpretations are proposed for the transect along the southeastern coast of the bay. The first model shows crustal thickening beneath the George River Shear Zone (GRSZ) and two shallow bodies correlated with the northern extensions of the GRSZ and the De Pas batholith. The second model shows constant crustal thickness and bodies more deeply rooted than in the first model. The gravity models are consistent with the easterly dipping reflections imaged along a Lithoprobe seismic line crossing Ungava Bay and suggest westward thrusting of the Rae Province over the NQO. Because no gravity data have been collected in Ungava Bay, satellite altimetry data have been used as a means to fill the gap in data collected at sea. The satellite-derived gravity data and standard Bouguer gravity data were combined in a composite map for the Ungava Bay region. The new land-based gravity measurements were used to verify and calibrate the satellite data and to ensure that offshore gravity anomalies merge with those determined by the land surveys in a reasonable fashion. Three parallel east-west gravity profiles were extracted: across Ungava Bay (59.9°N), on the southern shore of the bay (58.5°N), and onshore ~200 km south of Ungava Bay (57.1°N). The gravity signature of some major structures, such as the GRSZ, can be identified on each profile.

A comparison between sea-bottom gravity and satellite altimeter-derived gravity in coastal environments: A case study of the Gulf of Manfredonia (SW Adriatic Sea)

2021 ◽  
Author(s):  
Luigi Sante Zampa ◽  
Emanuele Lodolo ◽  
Nicola Creati ◽  
Martina Busetti ◽  
Gianni Madrussani ◽  
...  
Keyword(s):  
Gravity Field ◽  
Satellite Altimetry ◽  
Adriatic Sea ◽  
Gravity Anomalies ◽  
Satellite Altimeter ◽  
Sea Bottom ◽  
Marine Gravity ◽  
Gravity Measurements ◽  
Near Shore ◽  
Italian Coasts

&lt;p&gt;In this study, we present a comparative analysis between two types of gravity data used in geophysical applications: satellite altimeter-derived gravity and sea-bottom gravity.&lt;/p&gt;&lt;p&gt;It is largely known that the marine gravity field derived from satellite altimetry in coastal areas is generally biased by signals back-scattered from the nearby land. As a result, the derived gravity anomalies are mostly unreliable for geophysical and geological interpretations of near-shore environments.&lt;/p&gt;&lt;p&gt;To quantify the errors generated by the land-reflected signals and to verify the goodness of the geologic models inferred from gravity, we compared two different altimetry models with sea-bottom gravity measurements acquired along the Italian coasts from the early 50s to the late 80s.&lt;/p&gt;&lt;p&gt;We focused on the Gulf of Manfredonia, located in the SE sector of the Adriatic Sea, where: (i) two different sea-bottom gravity surveys have been conducted over the years, (ii) the bathymetry is particularly flat, and (iii) seismic data revealed a prominent carbonate ridge covered by hundreds of meters of Oligocene-Quaternary sediments.&lt;/p&gt;&lt;p&gt;Gravity field derivatives have been used to enhance both: (i) deep geological contacts, and (ii) coastal noise. The analyses outlined a &amp;#8220;ringing-noise effect&amp;#8221; which causes the altimeter signal degradation up to 17 km from the coast.&lt;/p&gt;&lt;p&gt;Differences between the observed gravity and the gravity calculated from a geological model constrained by seismic, showed that all datasets register approximately the same patterns, associated with the Gondola Fault Zone, a major structural discontinuity traversing roughly E-W the investigated area.&lt;/p&gt;&lt;p&gt;This study highlights the importance of implementing gravity anomalies derived from satellite-altimetry with high-resolution near-shore data, such as the sea-bottom gravity measurements available around the Italian coasts. Such analysis may have significant applications in studying the link between onshore and offshore geological structures in transitional areas.&lt;/p&gt;

Red Snapper: Ecology and Fisheries in the U.S. Gulf of Mexico

2007 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Red Snapper ◽  
Lutjanus Campechanus ◽  
Nursery Areas ◽  
Side Scan Sonar ◽  
Bathymetric Data ◽  
Habitat Effect ◽  
Inner Continental Shelf ◽  
The U.S ◽  
Trawl Surveys

<em>Abstract.</em>—Trawl surveys were conducted to measure patterns of habitat use by newly settled red snapper <em>Lutjanus campechanus </em>at three natural banks on the inner continental shelf of Texas. Digital side-scan sonar and multibeam bathymetric data were used to define inshore (mud), ridge (shell), and offshore (mud) habitats for Freeport Rocks, Heald Bank, and Sabine Bank. Otter trawls were conducted July through September in 2003 (Heald Bank, Sabine Bank) and in 2004 (Freeport Rocks) during the settlement period of red snapper. Freeport Rocks had markedly higher densities of red snapper (91 ha<sup>⁻1</sup>) in 2004 than Heald Bank (6 ha<sup>⁻1</sup>) or Sabine Bank (<1 ha<sup>⁻1</sup>) in 2003. A significant habitat effect was observed at Heald Bank and densities were higher at offshore mud habitats; no habitat effect was detected for Freeport Rocks or Sabine Bank. Growth rates varied from 0.86 mm‧d<sup>⁻1</sup> at Sabine Bank up to 1.12 mm‧d<sup>⁻1</sup> at Freeport Rocks, and rates were higher on inshore and offshore mud than ridge habitats. Otolith-based estimates of age indicated that settlers were first detected at 22–28 d and the majority of individuals were 30–60 d. Hatch dates peaked from early June to early July in both 2003 and 2004. Results from this study indicate that both shell and inshore and offshore mud habitats associated with these natural banks serve as settlement habitat of red snapper, and all three habitats have the potential to function as nursery areas of this species.

Present-Day Methods of Depth Measurement

2000 ◽  
Author(s):  
John Hughes Clarke
Keyword(s):  
Continental Shelf ◽  
Traditional Approach ◽  
Acoustic Pulse ◽  
Acoustic Energy ◽  
Sea Surface ◽  
Optimal Method ◽  
Single Beam ◽  
Bathymetric Data ◽  
Incomplete Coverage

Bathymetric data are needed to derive the morphological criteria that define the extent of the juridical continental shelf. Two features in particular, the '"foot of slope" and the 2500-m contour, must be defined. The previous chapter considered historical methods of determining bathymetry. This chapter will cover the present day methods that can be used to better meet the need for accurate bathymetry. In order to satisfy the demands of UNCLOS, bathymetric data are required in depths ranging from about 200 m to more than 5000 m. Shallower depths, while useful for demonstrating the morphology of the physical continental shelf, do not bear any relevance to the delineation of juridical continental shelf boundaries, other than where they are required to establish the baseline. Alternate methods to derive bathymetry other than using sound are available. Those involving airborne electromagnetic methods (e.g., electromagnetic induction, red-green lasers, and inversion of sea surface radar images) are not capable of determining depths much in excess of 40 m. The only other method potentially useful for deriving deeper water bathymetry is through inversion of sea surface altimetry obtained from satellites. This will be discussed at the end of this chapter. The optimal method thus remains acoustic. The traditional approach has been to use single-beam echo sounders (see previous chapter). This chapter discusses the more modern '"swath" sonar techniques, which are becoming widely used. The great majority of historic bathymetry has been collected using the single-beam sounding approach. As discussed in chapter 9, this method has a number of limitations, three of the most critical of which are i. incomplete coverage; ii. uncertainty about the exact location of the first arrival of the acoustic pulse; and iii. distortion of short-wavelength topography. In order to achieve more complete coverage, better echo location, and higher spatial resolution, methods were devised to project acoustic energy both within narrower solid angles (figure 10.1) and while deriving this information over angular sectors extending further out from the side of the survey vessel. All the methods commonly applied involved scanning the seabed orthogonal to the ship heading. Sequential scans, accumulated as the ship progresses, form a corridor (or swath) of seabed information (figure 10.2).

scholarly journals The Reduction Method of Bathymetric Datasets that Preserves True Geodata

2019 ◽  
Vol 11 (13) ◽  
pp. 1610 ◽  
Author(s):  
Marta Wlodarczyk-Sielicka ◽  
Andrzej Stateczny ◽  
Jacek Lubczonek
Keyword(s):  
Data Reduction ◽  
Reduction Method ◽  
Large Data ◽  
Water Area ◽  
Bathymetric Data ◽  
Remote Sensors ◽  
Depth Data ◽  
Coastal Modelling ◽  
Reduction Methods ◽  
Quality And Reliability

Water areas occupy over 70 percent of the Earth’s surface and are constantly subject to research and analysis. Often, hydrographic remote sensors are used for such research, which allow for the collection of information on the shape of the water area bottom and the objects located on it. Information about the quality and reliability of the depth data is important, especially during coastal modelling. In-shore areas are liable to continuous transformations and they must be monitored and analyzed. Presently, bathymetric geodata are usually collected via modern hydrographic systems and comprise very large data point sequences that must then be connected using long and laborious processing sequences including reduction. As existing bathymetric data reduction methods utilize interpolated values, there is a clear requirement to search for new solutions. Considering the accuracy of bathymetric maps, a new method is presented here that allows real geodata to be maintained, specifically position and depth. This study presents a description of a developed method for reducing geodata while maintaining true survey values.

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