To see the other types of publications on this topic, follow the link: Bathymetry.
Journal articles on the topic 'Bathymetry'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Bathymetry.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Yeu, Yeon, Jurng-Jae Yee, Hong Yun, and Kwang Kim. "Evaluation of the Accuracy of Bathymetry on the Nearshore Coastlines of Western Korea from Satellite Altimetry, Multi-Beam, and Airborne Bathymetric LiDAR." Sensors 18, no. 9 (September 3, 2018): 2926. http://dx.doi.org/10.3390/s18092926.
Full textAbstract:
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.
2
Bures, Ludek, Petra Sychova, Petr Maca, Radek Roub, and Stepan Marval. "River Bathymetry Model Based on Floodplain Topography." Water 11, no. 6 (June 20, 2019): 1287. http://dx.doi.org/10.3390/w11061287.
Full textAbstract:
An appropriate digital elevation model (DEM) is required for purposes of hydrodynamic modelling of floods. Such a DEM describes a river’s bathymetry (bed topography) as well as its surrounding area. Extensive measurements for creating accurate bathymetry are time-consuming and expensive. Mathematical modelling can provide an alternative way for representing river bathymetry. This study explores new possibilities in mathematical depiction of river bathymetry. A new bathymetric model (Bathy-supp) is proposed, and the model’s ability to represent actual bathymetry is assessed. Three statistical methods for the determination of model parameters were evaluated. The best results were achieved by the random forest (RF) method. A two-dimensional (2D) hydrodynamic model was used to evaluate the influence of the Bathy-supp model on the hydrodynamic modelling results. Also presented is a comparison of the proposed model with another state-of-the-art bathymetric model. The study was carried out on a reach of the Otava River in the Czech Republic. The results show that the proposed model’s ability to represent river bathymetry exceeds that of his current competitor. Use of the bathymetric model may have a significant impact on improving the hydrodynamic model results.
3
Palaseanu-Lovejoy, Monica, Oleg Alexandrov, Jeff Danielson, and Curt Storlazzi. "SaTSeaD: Satellite Triangulated Sea Depth Open-Source Bathymetry Module for NASA Ames Stereo Pipeline." Remote Sensing 15, no. 16 (August 9, 2023): 3950. http://dx.doi.org/10.3390/rs15163950.
Full textAbstract:
We developed the first-ever bathymetric module for the NASA Ames Stereo Pipeline (ASP) open-source topographic software called Satellite Triangulated Sea Depth, or SaTSeaD, to derive nearshore bathymetry from stereo imagery. Correct bathymetry measurements depend on water surface elevation, and whereas previous methods considered the water surface horizontal, our bathymetric module accounts for the curvature of the Earth in the imagery. The process is semiautomatic, reliable, and repeatable, independent of any external bathymetry data eliminating user bias in selecting bathymetry calibration points, and it can generate a fully integrated and seamless topo-bathymetry digital elevation model (TBDEM) in the same coordinate system, comparable with the band-ratio method irrespective of the regression method used for the band-ratio algorithm. The ASP output can be improved by applying a camera bundle adjustment to minimize reprojection errors and by alignment to a more accurate topographic (above water) surface without any bathymetric input since the derived TBDEM is a rigid surface. These procedures can decrease bathymetry root mean square errors from 30 to 80 percent, depending on environmental conditions, the quality of satellite imagery, and the spectral band used (e.g., blue, green, or panchromatic).
4
Guo, Xiaozu, Xiaoyi Jin, and Shuanggen Jin. "Shallow Water Bathymetry Mapping from ICESat-2 and Sentinel-2 Based on BP Neural Network Model." Water 14, no. 23 (November 27, 2022): 3862. http://dx.doi.org/10.3390/w14233862.
Full textAbstract:
Accurate shallow water bathymetry data are essential for coastal construction and management, marine traffic, and shipping. With the development of remote sensing satellites and sensors, the satellite-derived bathymetry (SDB) method has been widely used for bathymetry in shallow water areas. However, traditional satellite bathymetry requires in-situ bathymetric data. Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) with the advanced high-resolution topographic laser altimeter system (ATLAS) provides a new technical tool and makes up for the shortcomings of traditional bathymetric methods in shallow waters. In this study, a new method is proposed to automatically detect photons reflected from the shallow seafloor with ICESat-2 altimetry data. Two satellite bathymetry models were trained, to obtain shallow water depth from Sentinel-2 satellite images. First, sea surface and seafloor signal photons from ICESat-2 were detected in the Oahu (in the U.S. Hawaiian Islands) and St. Thomas (in the U.S. Virgin Islands) sampling areas, to obtain water depths along the surface track. The results show that the RMSE is between 0.35 and 0.71 m and the R2 is greater than 0.92, when compared to the airborne LiDAR bathymetry (ALB) data in the field. Second, the ICESat-2 bathymetric points from Oahu Island are used to train the Back Propagation (BP) neural network model and obtain the SDB. The RMSE is between 0.97 and 1.43 m and the R2 is between 0.90 and 0.96, which are better than the multi-band ratio model with RMSE of 1.03–1.57 m and R2 of 0.89–0.95. The results show that the BP neural network model can effectively improve bathymetric accuracy, when compared to the traditional multi-band ratio model. This approach can obtain shallow water bathymetry more easily, without the in-situ bathymetric data. Therefore, it extends to a greater extent with the free ICESat-2 and Sentinel-2 satellite data for bathymetry in shallow water areas, such as coastal, island and inland water bodies.
5
Le, Yuan, Mengzhi Hu, Yifu Chen, Qian Yan, Dongfang Zhang, Shuai Li, Xiaohan Zhang, and Lizhe Wang. "Investigating the Shallow-Water Bathymetric Capability of Zhuhai-1 Spaceborne Hyperspectral Images Based on ICESat-2 Data and Empirical Approaches: A Case Study in the South China Sea." Remote Sensing 14, no. 14 (July 15, 2022): 3406. http://dx.doi.org/10.3390/rs14143406.
Full textAbstract:
Accurate bathymetric and topographical information is crucial for coastal and marine applications. In the past decades, owing to its low cost and high efficiency, satellite-derived bathymetry has been widely used to estimate the depth of shallow water in coastal areas. However, insufficient spectral bands and availability of in situ water depths limit the application of satellite-derived bathymetry. Currently, the investigation about the bathymetric potential of hyperspectral imaging is relatively insufficient based on datasets of the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2). In this study, Zhuhai-1 hyperspectral images and ICESat-2 datasets were utilized to perform nearshore bathymetry and explore the bathymetric capability by selecting different bands based on classical empirical models (the band ratio model and the linear band model). Furthermore, experimental results achieved at the South China Sea indicate that the combination of blue (2 and 3 band) and green (9 band) bands and the combination of red (10 and 12 band) and near-infrared (29 band) bands are most suitable to achieve nearshore bathymetry. Correspondingly, the highest accuracy of bathymetry reached root mean square error values of 0.98 m and 1.19 m for different band combinations evaluated through bathymetric results of reference water depth. The bathymetric accuracy of Zhuhai-1 image is similar with that of Sentinel-2 when employing the blue and green bands. The combination of red and near-infrared bands has a higher bathymetric accuracy for Zhuhai-1 image than that for Sentinel-2 image.
6
Mukhamedina, A. Ye, D. K. Abiyeva, and K. M. Kulebayev. "Assessment of the potential use of ICESat-2 data for bathymetric mapping of small lakes of Kazakhstan." Geography and water resources, no. 2 (June 30, 2022): 43–49. http://dx.doi.org/10.55764/2957-9856/2022-2-43-49.12.
Full textAbstract:
Lake bathymetry is of great importance for water resources management and hydrological modeling. Bathymetric mapping of lakes was predominantly conducted with the use of highly-priced methods such as airborne lidars, active imaging sonars, multibeam echosounders. With the advancements in GIS and emergence of remotely sensed data new approaches for bathymetry extraction were developed. However, despite a high motivation to obtain bathymetric information for small lakes from remotely sensed data, there is a lack of reliable methods that can be implemented under various climate conditions and on a wide scale. In this paper several remote-sensing-based methods for bathymetry mapping of small lakes are discussed. The new Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) data was used to extract bathymetric information on three small lakes of Kazakhstan. The assessment of ICESat-2 for lake bathymetry extraction was conducted using field measurements as the validation data.
7
Li, Yuguo, and Steven Constable. "2D marine controlled-source electromagnetic modeling: Part 2 — The effect of bathymetry." GEOPHYSICS 72, no. 2 (March 2007): WA63—WA71. http://dx.doi.org/10.1190/1.2430647.
Full textAbstract:
Marine controlled-source electromagnetic (CSEM) data are strongly affected by bathymetry because of the conductivity contrast between seawater and the crust below the seafloor. We simulate the marine CSEM response to 2D bathymetry using our new finite element (FE) code, and our numerical modeling shows that all electric and magnetic components are influenced by bathymery, but to different extents. Bathymetry effects depend upon transmission frequency, seabed conductivity, seawater depth, transmitter-receiver geometry, and roughness of the seafloor topography. Bathymetry effects clearly have to be take into account to avoid the misinterpretation of marine CSEM data sets.
8
Xie, Yiping, Nils Bore, and John Folkesson. "Sidescan Only Neural Bathymetry from Large-Scale Survey." Sensors 22, no. 14 (July 6, 2022): 5092. http://dx.doi.org/10.3390/s22145092.
Full textAbstract:
Sidescan sonar is a small and low-cost sensor that can be mounted on most unmanned underwater vehicles (UUVs) and unmanned surface vehicles (USVs). It has the advantages of high resolution and wide coverage, which could be valuable in providing an efficient and cost-effective solution for obtaining the bathymetry when bathymetric data are unavailable. This work proposes a method of reconstructing bathymetry using only sidescan data from large-scale surveys by formulating the problem as a global optimization, where a Sinusoidal Representation Network (SIREN) is used to represent the bathymetry and the albedo and the beam profile are jointly estimated based on a Lambertian scattering model. The assessment of the proposed method is conducted by comparing the reconstructed bathymetry with the bathymetric data collected with a high-resolution multi-beam echo sounder (MBES). An error of 20 cm on the bathymetry is achieved from a large-scale survey. The proposed method proved to be an effective way to reconstruct bathymetry from sidescan sonar data when high-accuracy positioning is available. This could be of great use for applications such as surface vehicles with Global Navigation Satellite System (GNSS) to obtain high-quality bathymetry in shallow water or small autonomous underwater vehicles (AUVs) if simultaneous localization and mapping (SLAM) can be applied to correct the navigation estimate.
9
Li, Jiwei, David E. Knapp, Mitchell Lyons, Chris Roelfsema, Stuart Phinn, Steven R. Schill, and Gregory P. Asner. "Automated Global Shallow Water Bathymetry Mapping Using Google Earth Engine." Remote Sensing 13, no. 8 (April 10, 2021): 1469. http://dx.doi.org/10.3390/rs13081469.
Full textAbstract:
Global shallow water bathymetry maps offer critical information to inform activities such as scientific research, environment protection, and marine transportation. Methods that employ satellite-based bathymetric modeling provide an alternative to conventional shipborne measurements, offering high spatial resolution combined with extensive coverage. We developed an automated bathymetry mapping approach based on the Sentinel-2 surface reflectance dataset in Google Earth Engine. We created a new method for generating a clean-water mosaic and a tailored automatic bathymetric estimation algorithm. We then evaluated the performance of the models at six globally diverse sites (Heron Island, Australia; West Coast of Hawaiʻi Island, Hawaiʻi; Saona Island, Dominican Republic; Punta Cana, Dominican Republic; St. Croix, United States Virgin Islands; and The Grenadines) using 113,520 field bathymetry sampling points. Our approach derived accurate bathymetry maps in shallow waters, with Root Mean Square Error (RMSE) values ranging from 1.2 to 1.9 m. This automatic, efficient, and robust method was applied to map shallow water bathymetry at the global scale, especially in areas which have high biodiversity (i.e., coral reefs).
10
Xie, Congshuang, Peng Chen, Delu Pan, Chunyi Zhong, and Zhenhua Zhang. "Improved Filtering of ICESat-2 Lidar Data for Nearshore Bathymetry Estimation Using Sentinel-2 Imagery." Remote Sensing 13, no. 21 (October 26, 2021): 4303. http://dx.doi.org/10.3390/rs13214303.
Full textAbstract:
The accurate estimation of nearshore bathymetry is necessary for multiple aspects of coastal research and practices. The traditional shipborne single-beam/multi-beam echo sounders and Airborne Lidar bathymetry (ALB) have a high cost, are inefficient, and have sparse coverage. The Satellite-derived bathymetry (SDB) method has been proven to be a promising tool in obtaining bathymetric data in shallow water. However, current empirical SDB methods for multispectral imagery data usually rely on in situ depths as control points, severely limiting their spatial application. This study proposed a satellite-derived bathymetry method without requiring a priori in situ data by merging active and passive remote sensing (SDB-AP). It realizes rapid bathymetric mapping with only satellite remotely sensed data, which greatly extends the spatial coverage and temporal scale. First, seafloor photons were detected from the ICESat-2 raw photons based on an improved adaptive Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, which could calculate the optimal detection parameters for seafloor photons by adaptive iteration. Then, the bathymetry of the detected seafloor photons was corrected because of the refraction that occurs at the air–water interface. Afterward, the outlier photons were removed by an outlier-removal algorithm to improve the retrieval accuracy. Subsequently, the high spatial resolution (0.7 m) ICESat-2 derived bathymetry data were gridded to match the Sentinel-2 data with a lower spatial resolution (10 m). All of the ICESate-2 gridded data were randomly separated into two parts: 80% were employed to train the empirical bathymetric model, and the remaining 20% were used to quantify the inversion accuracy. Finally, after merging the ICESat-2 data and Sentinel-2 multispectral images, the bathymetric maps over St. Thomas of the United States Virgin Islands, Acklins Island in the Bahamas, and Huaguang Reef in the South China Sea were produced. The ICESat-2-derived results were compared against in situ data over the St. Thomas area. The results showed that the estimated bathymetry reached excellent inversion accuracy and the corresponding RMSE was 0.68 m. In addition, the RMSEs between the SDB-AP estimated depths and the ICESat-2 bathymetry results of St. Thomas, Acklins Island, and Huaguang Reef were 0.96 m, 0.91 m, and 0.94 m, respectively. Overall, the above results indicate that the SDB-AP method is effective and feasible for different shallow water regions. It has great potential for large-scale and long-term nearshore bathymetry in the future.
11
Wu, Yihao, Junjie Wang, Yueqian Shen, Dongzhen Jia, and Yu Li. "Bathymetry Refinement over Seamount Regions from SAR Altimetric Gravity Data through a Kalman Fusion Method." Remote Sensing 15, no. 5 (February 26, 2023): 1288. http://dx.doi.org/10.3390/rs15051288.
Full textAbstract:
Seafloor topography over seamount areas is crucial for studying plate motions, seafloor seismicity, and seamount ecosystems. However, seamount bathymetry modeling is difficult due to the complex hydrodynamic environment, biodiversity, and scarcity of shipborne echo sounding data. The use of satellite altimeter-derived gravity data is a complementary way of bathymetry computation; in particular, the incorporation of synthetic aperture radar (SAR) altimeter data may be useful for seamount bathymetry modeling. Moreover, the widely used filtering method may have difficulty in combing different bathymetry data sets and may affect the quality of the computed bathymetry. To mitigate this issue, we introduce a Kalman fusion method for weighting and combining gravity-derived bathymetry data and the reference bathymetry model. Numerical experiments in the seamount regions over the Molloy Ridge show that the use of SAR-based altimetric gravity data improves the local bathymetry model, by a magnitude of 14.27 m, compared to the result without SAR data. In addition, the developed Kalman fusion method outperforms the traditionally used filtering method, and the bathymetry computed from the Kalman fusion method is improved by a magnitude of 9.34 m. Further comparison shows that our solution has improved quality compared to a recently released global bathymetry model, namely, GEBCO 2022 (GEBCO: General Bathymetric Chart of the Oceans), by a magnitude of 34.34 m. The bathymetry model in this study may be substituted for existing global bathymetry models for geophysical investigations over the target area.
12
Wang, Jiali, Ming Chen, Weidong Zhu, Liting Hu, and Yasong Wang. "A Combined Approach for Retrieving Bathymetry from Aerial Stereo RGB Imagery." Remote Sensing 14, no. 3 (February 7, 2022): 760. http://dx.doi.org/10.3390/rs14030760.
Full textAbstract:
Shallow water bathymetry is critical in understanding and managing marine ecosystems. Bathymetric inversion models using airborne/satellite multispectral data are an efficient way to retrieve shallow bathymetry due to the affordable cost of airborne/satellite images and less field work required. With the increasing availability and popularity of unmanned aerial vehicle (UAV) imagery, this paper explores a new approach to obtain bathymetry using UAV visual-band (RGB) images. A combined approach is therefore proposed for retrieving bathymetry from aerial stereo RGB imagery, which is the combination of a new stereo triangulation method (an improved projection image based two-medium stereo triangulation method) and spectral inversion models. In general, the inversion models require some bathymetry reference points, which are not always feasible in many scenarios, and the proposed approach employs a new stereo triangulation method to obtain reliable bathymetric points, which act as the reference points of the inversion models. Using various numbers of triangulation points as the reference points together with a Geographical Weighted Regression (GWR) model, a series of experiments were conducted using UAV RGB images of a small island, and the results were validated against LiDAR points. The promising results indicate that the proposed approach is an efficient technique for shallow water bathymetry retrieval, and together with UAV platforms, it could be deployed easily to conduct a broad range of applications within marine environments.
13
Wang, Yingxi, Ming Chen, Xiaotao Xi, and Hua Yang. "Bathymetry Inversion Using Attention-Based Band Optimization Model for Hyperspectral or Multispectral Satellite Imagery." Water 15, no. 18 (September 8, 2023): 3205. http://dx.doi.org/10.3390/w15183205.
Full textAbstract:
Satellite-derived bathymetry enables the non-contact derivation of large-scale shallow water depths. Hyperspectral satellite images provide more information than multispectral satellite images, making them theoretically more effective and accurate for bathymetry inversion. This paper focuses on the use of hyperspectral satellite images (PRISMA) for bathymetry inversion and compares the retrieval capabilities of multispectral satellite images (Sentinel-2 and Landsat 9) in the southeastern waters of Molokai Island in the Hawaiian Archipelago and Yinyu Island in the Paracel Archipelago. This paper proposes an attention-based band optimization one-dimensional convolutional neural network model (ABO-CNN) to better utilize the increased spectral information from multispectral and hyperspectral images for bathymetry inversion, and this model is compared with a traditional empirical model (Stumpf model) and two deep learning models (feedforward neural network and one-dimensional convolutional neural network). The results indicate that the ABO-CNN model outperforms the above three models, and the root mean square errors of retrieved bathymetry using the PRISMA images are 1.43 m and 0.73 m in the above two study areas, respectively. In summary, this paper demonstrates that PRISMA hyperspectral imagery has superior bathymetry inversion capabilities compared to multispectral images (Sentinel-2 and Landsat 9), and the proposed deep learning model ABO-CNN is a promising candidate model for satellite-derived bathymetry using hyperspectral imagery. With the increasing availability of ICESat-2 bathymetric data, the use of a combination of the proposed ABO-CNN model and the ICEsat-2 data as the training data provides a practical approach for bathymetric retrieval applications.
14
Wolfe, Christopher L., and Claudia Cenedese. "Laboratory Experiments on Eddy Generation by a Buoyant Coastal Current Flowing over Variable Bathymetry*." Journal of Physical Oceanography 36, no. 3 (March 1, 2006): 395–411. http://dx.doi.org/10.1175/jpo2857.1.
Full textAbstract:
Abstract Irminger rings are warm-core eddies formed off the west coast of Greenland. Recent studies suggest that these eddies, which are implicated in the rapid springtime restratification of the Labrador Sea, are formed by an internal instability of the West Greenland Current (WGC), triggered by bathymetric variations. This study seeks to explore the effect of the magnitude and downstream length scale of bathymetric variations on the stability of a simple model of the WGC in a series of laboratory experiments in which a buoyant coastal current was allowed to flow over bathymetry consisting of piecewise constant slopes of varying magnitude. The currents did not form eddies over gently sloping bathymetry and only formed eddies over steep bathymetry if the current width exceeded the width of the sloping bathymetry. Eddying currents were immediately stabilized if they flowed onto gently sloping topography. Bathymetric variations that persisted only a short distance downstream perturbed the flow locally but did not lead to eddy formation. Eddies formed only once the downstream length of the bathymetric variations exceeded a critical scale of about 8 Rossby radii. These results are consistent with the observed behavior of the WGC, which begins to form Irminger rings after entering a region where the continental slope abruptly steepens and becomes narrower than the WGC itself in a region spanning about 20–80 Rossby radii of downstream distance.
15
Le Quilleuc, Alyson, Antoine Collin, Michael F. Jasinski, and Rodolphe Devillers. "Very High-Resolution Satellite-Derived Bathymetry and Habitat Mapping Using Pleiades-1 and ICESat-2." Remote Sensing 14, no. 1 (December 29, 2021): 133. http://dx.doi.org/10.3390/rs14010133.
Full textAbstract:
Accurate and reliable bathymetric data are needed for a wide diversity of marine research and management applications. Satellite-derived bathymetry represents a time saving method to map large shallow waters of remote regions compared to the current costly in situ measurement techniques. This study aims to create very high-resolution (VHR) bathymetry and habitat mapping in Mayotte island waters (Indian Ocean) by fusing 0.5 m Pleiades-1 passive multispectral imagery and active ICESat-2 LiDAR bathymetry. ICESat-2 georeferenced photons were filtered to remove noise and corrected for water column refraction. The bathymetric point clouds were validated using the French naval hydrographic and oceanographic service Litto3D® dataset and then used to calibrate the multispectral image to produce a digital depth model (DDM). The latter enabled the creation of a digital albedo model used to classify benthic habitats. ICESat-2 provided bathymetry down to 15 m depth with a vertical accuracy of bathymetry estimates reaching 0.89 m. The benthic habitats map produced using the maximum likelihood supervised classification provided an overall accuracy of 96.62%. This study successfully produced a VHR DDM solely from satellite data. Digital models of higher accuracy were further discussed in the light of the recent and near-future launch of higher spectral and spatial resolution satellites.
16
Zhu, Siyu, Baojian Liu, Wei Wan, Hongjie Xie, Yu Fang, Xi Chen, Huan Li, et al. "A New Digital Lake Bathymetry Model Using the Step-Wise Water Recession Method to Generate 3D Lake Bathymetric Maps Based on DEMs." Water 11, no. 6 (May 31, 2019): 1151. http://dx.doi.org/10.3390/w11061151.
Full textAbstract:
The availability of lake bathymetry maps is imperative for estimating lake water volumes and their variability, which is a sensitive indicator of climate. It is difficult, if not impossible, to obtain bathymetric measurements from all of the thousands of lakes across the globe due to costly labor and/or harsh topographic regions. In this study, we develop a new digital lake bathymetry model (DLBM) using the step-wise water recession method (WRM) to generate 3-dimensional lake bathymetric maps based on the digital elevation model (DEM) alone, with two assumptions: (1) typically, the lake’s bathymetry is formed and shaped by geological processes similar to those that shaped the surrounding landmasses, and (2) the agent rate of water (the thickness of the sedimentary deposit proportional to the lake water depth) is uniform. Lake Ontario and Lake Namco are used as examples to demonstrate the development, calibration, and refinement of the model. Compared to some other methods, the estimated 3D bathymetric maps using the proposed DLBM could overcome the discontinuity problem to adopt the complex topography of lake boundaries. This study provides a mathematically robust yet cost-effective approach for estimating lake volumes and their changes in regions lacking field measurements of bathymetry, for example, the remote Tibetan Plateau, which contains thousands of lakes.
17
Ouellette Jr., Gilman, Kira Fargo, and Henry Charry. "Satellite computed bathymetry assessment – Developing satellite LiDAR methods to enhance coastal bathymetry coverage." International Hydrographic Review 29, no. 2 (November 1, 2023): 208–12. http://dx.doi.org/10.58440/ihr-29-2-n05.
Full textAbstract:
The Satellite Computed Bathymetry Assessment (SCuBA) project implements a new photon classification approach to prepare lidar returns from the ICESat-2 satellite mission as a source of bathymetric data in suitable shallow ocean environments. SCuBA data enhances and compliments other space-borne bathymetry estimation methods for hydrographic applications and improves depth uncertainty where applicable. Incorporating SCuBA data into hydrographic projects expands and enhances data collection capabilities that can inform other empirical satellite bathymetry models and help improve navigational safety products in areas where ship-based sonar and aircraft-borne lidar surveys are not feasible.
18
Ghorbanidehno, Hojat, Jonghyun Lee, Matthew Farthing, Tyler Hesser, Peter K. Kitanidis, and Eric F. Darve. "Novel Data Assimilation Algorithm for Nearshore Bathymetry." Journal of Atmospheric and Oceanic Technology 36, no. 4 (April 2019): 699–715. http://dx.doi.org/10.1175/jtech-d-18-0067.1.
Full textAbstract:
AbstractIt can be expensive and difficult to collect direct bathymetry data for nearshore regions, especially in high-energy locations where there are temporally and spatially varying bathymetric features like sandbars. As a result, there has been increasing interest in remote assessment techniques for estimating bathymetry. Recent efforts have combined Kalman filter–based techniques with indirect video-based observations for bathymetry inversion. Here, we estimate nearshore bathymetry by utilizing observed wave celerity and wave height, which are related to bathymetry through phase-averaged wave dynamics. We present a modified compressed-state Kalman filter (CSKF) method, a fast and scalable Kalman filter method for linear and nonlinear problems with large numbers of unknowns and measurements, and apply it to two nearshore bathymetry estimation problems. To illustrate the robustness and accuracy of our method, we compare its performance with that of two ensemble-based approaches on twin bathymetry estimation problems with profiles based on surveys taken by the U.S. Army Corps of Engineer Field Research Facility (FRF) in Duck, North Carolina. We first consider an estimation problem for a temporally constant bathymetry profile. Then we estimate bathymetry as it evolves in time. Our results indicate that the CSKF method is more accurate and robust than the ensemble-based methods with the same computational cost. The superior performance is due to the optimal low-rank representation of the covariance matrices.
19
Basith, Abdul, and Ratna Prastyani. "EVALUATING ACOMP, FLAASH AND QUAC ON WORLDVIEW-3 FOR SATELLITE DERIVED BATHYMETRY (SDB) IN SHALLOW WATER." Geodesy and cartography 46, no. 3 (October 29, 2020): 151–58. http://dx.doi.org/10.3846/gac.2020.11426.
Full textAbstract:
Bathymetry map is instrumental for monitoring marine ecosystem and supporting marine transportation. Optical satellite imagery has been widely utilised as an alternative method to derive bathymetry map in shallow water. Nonetheless, interactions between electromagnetic energy and Earth’s atmosphere causing the atmosphere effects pose a significant challenge in satellite-derived bathymetry (SDB) application. In this study, Worldview-3 imagery was used to obtain bathymetry map in shallow water. Three atmospheric correction models (ACOMP, FLAASH and QUAC) were employed to eliminate atmospheric effects on Worldview-3 imagery. Three simple band ratios involving coastal blue, blue, green and yellow band were used to test the performance of atmospheric correction models. ACOMP combined with blue and green band ratio efficaciously provided the best performance where it explained 77% of model values. Bathymetry map obtained from Worldview-3 was also validated using bathymetry data acquired from bathymetric survey over the study area. The estimated depths shared aggregable results with measured depths (depth < 20 m) with accuracy of 2.07 m. This study shows that robust atmospheric correction combined with suitable simple band combinations offered bathymetry map retrieval with relatively high accuracy.
20
Alevizos, Evangelos. "A Combined Machine Learning and Residual Analysis Approach for Improved Retrieval of Shallow Bathymetry from Hyperspectral Imagery and Sparse Ground Truth Data." Remote Sensing 12, no. 21 (October 23, 2020): 3489. http://dx.doi.org/10.3390/rs12213489.
Full textAbstract:
Mapping shallow bathymetry by means of optical remote sensing has been a challenging task of growing interest in recent years. Particularly, many studies exploit earlier empirical models together with the latest multispectral satellite imagery (e.g., Sentinel 2, Landsat 8). However, in these studies, the accuracy of resulting bathymetry is (a) limited for deeper waters (>15 m) and/or (b) is being influenced by seafloor type albedo. This study explores further the capabilities of hyperspectral satellite imagery (Hyperion), which provides several spectral bands in the visible spectrum, along with existing reference bathymetry. Bathymetry predictors are created by applying the semi-empirical approach of band ratios on hyperspectral imagery. Then, these predictors are fed to machine learning regression algorithms for predicting bathymetry. Algorithm performance is being further compared to bathymetry predictions from multiple linear regression analysis. Following the initial predictions, the residual bathymetry values are interpolated by applying the Ordinary Kriging method. Then, the predicted bathymetry from all three algorithms along with their associated residual grids is used as predictors at a second processing stage. Validation results show that by using a second stage of processing, the root-mean-square error values of predicted bathymetry is being improved by ≈1 m even for deeper water (up to 25 m). It is suggested that this approach is suitable for (a) contributing wide-scale, high-resolution shallow bathymetry toward the goals of the Seabed 2030 program and (b) as a coarse resolution alternative to effort-consuming single-beam sonar or costly airborne bathymetric laser surveying.
21
Herterich, James G., and Frédéric Dias. "Extreme long waves over a varying bathymetry." Journal of Fluid Mechanics 878 (September 17, 2019): 481–501. http://dx.doi.org/10.1017/jfm.2019.618.
Full textAbstract:
Recent modelling work has shown that abrupt bathymetric transitions can produce dramatic amplifications of long waves, under the influence of both nonlinearity and dispersion. Here, the evolution of wave packets towards a vertical wall over a varying bathymetry is investigated with a one-dimensional conformal-mapping spectral code. In this system, wave breaking, runup and reflection, wave interference and bathymetric effects are highlighted. Wave breaking is examined with respect to geometric, kinematic and energetic conditions, with consistent results. The breaking strength is characterized for spilling and plunging based on initial wave period and amplitude. Non-breaking waves are amplified by reflection, interference and the bathymetry leading to large runups. In a typical example inspired by a real-world bathymetry, the maximum runup amplification approaches a factor of 12 – large enough for a 3 m amplitude wave to overtop a 30 m cliff.
22
Fretwell, P. T., A. J. Tate, T. J. Deen, and M. Belchier. "Compilation of a new bathymetric dataset of South Georgia." Antarctic Science 21, no. 2 (December 2, 2008): 171–74. http://dx.doi.org/10.1017/s0954102008001703.
Full textAbstract:
AbstractWe introduce a new bathymetric compilation of the area around South Georgia in the Southern Ocean. Using a variety of data sources including multi and single-beam swath bathymetry we have constructed a gridded bathymetric dataset of the shelf and near-shelf sea-floor areas. The grid has been constructed using a layered hierarchy dependent upon accuracy of each dataset. The spikes and errors have been checked both manually and with a novel semi-automated process. We discuss the resulting bathymetry and the potential uses of the new dataset.
23
Bolaños, Rodolfo, Lars Boye Hansen, Mikkel Lydholm Rasmussen, Maziar Golestani, Jesper Sandvig Mariegaard, and Lisbeth Tangaa Nielsen. "COASTAL BATHYMETRY FROM SATELLITE AND ITS USE ON COASTAL MODELLING." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 98. http://dx.doi.org/10.9753/icce.v36.papers.98.
Full textAbstract:
Offshore wind farms around the world are being developed with the objective of increasing the contribution of renewable energy to the global energy consumption. Bathymetric features at the wind farm sites have a strong influence on waves and currents, controlling the propagation and dissipation of flows during normal and extreme conditions. In this work we use a state-of-the-art cost-effective method for bathymetric mapping based on high resolution satellite images to characterize a coastal wind farm region and assess the added value of such data when performing wave modelling. The study area is characterized by the presence of offshore wind farms and a complex bathymetry that feature sand bars and channels. For this study, a satellite derived bathymetry (SDB) was produced using imagery from the Sentinel-2A satellite. The Sentinel-2a data allows for more detailed SDB retrieval than is available in the existing accessible bathymetric datasets. The data is then used in a spectral wave model (MIKE21SW) with different resolutions outlining the impact of large bedforms on surface waves, mainly due to wave breaking. The bathymetry data is also used in a phase-resolving model (MIKE3waveFM) where regular and irregular waves are simulated, outlining the impact of bedforms on individual wave dissipation. Discussion on the satellite derived bathymetry and wave models results are presented in this paper.
24
Cui, Jiaxin, Xiaowen Luo, Ziyin Wu, Jieqiong Zhou, Hongyang Wan, Xiaolun Chen, and Xiaoming Qin. "High-Precision Inversion of Shallow Bathymetry under Complex Hydrographic Conditions Using VGG19—A Case Study of the Taiwan Banks." Remote Sensing 15, no. 5 (February 24, 2023): 1257. http://dx.doi.org/10.3390/rs15051257.
Full textAbstract:
Shallow bathymetry is important for ocean exploration, and the development of high-precision bathymetry inversion methods, especially for shallow waters with poor quality, is a major research aim. Synthetic aperture radar (SAR) image data benefit from a wide coverage, high measurement density, rapidity, and low consumption but are limited by low accuracy. Alternatively, multibeam data have low coverage and are difficult to obtain but have a high measurement accuracy. In this paper, taking advantage of the complementary properties, we use SAR image data as the content map and multibeam images as the migrated style map, applying the VGG19 neural network (optimizing the loss function formula) for bathymetric inversion. The model was universal and highly accurate for bathymetric inversion of shallow marine areas, such as turbid water in Taiwan. There was a strong correlation between bathymetric inversion data and measured data (R2 = 0.8822; RMSE = 1.86 m). The relative error was refined by 9.22% over those of previous studies. Values for different bathymetric regions were extremely correlated in the region of 20–40 m. The newly developed approach is highly accurate over 20 m in the open ocean, providing an efficient, precise shallow bathymetry inversion method for complex hydrographic conditions.
25
Lubis, Muhammad Zainuddin, Sri Pujiyati, Budhi Agung Prasetyo, and Tiggi Choanji. "Review : Bathymetry Mapping Using Underwater Acoustic Technology." Journal of Geoscience, Engineering, Environment, and Technology 4, no. 2 (June 30, 2019): 135. http://dx.doi.org/10.25299/jgeet.2019.4.2.3127.
Full textAbstract:
The bathymetry mapping using underwater acoustic technology very important in Indonesia waters. Bathymetry is the result of measuring the height of the seabed so that the bathymetric map provides information about the seabed, where this information can provide benefits to several fields related to the seabed. In bathymetry mapping uses underwater acoustic technology where among them is using Single beam echosounder and MBES (Multibeam Echosounder System), and multibeam echosounder (MBES) is acoustic equipment that is intensively used frequently in basic waters mapping. The advantage of using underwater acoustic technology is the acquisition and processing of data in real time, high accuracy and precision (correction of the bathymetry data was carried out with reference to the 2008 International Hydrographic Organization (IHO), and cannot be a threat or damage to objects. Retrieval of bathymetry data must use parallel patterns, namely: patterns with perpendicular sounding directions and tend to be parallel to longitudinal lines or in accordance with parallel sounding patterns.
26
Mudiyanselage, Sanduni D., Ben Wilkinson, and Amr Abd-Elrahman. "Automated High-Resolution Bathymetry from Sentinel-1 SAR Images in Deeper Nearshore Coastal Waters in Eastern Florida." Remote Sensing 16, no. 1 (December 19, 2023): 1. http://dx.doi.org/10.3390/rs16010001.
Full textAbstract:
Synthetic aperture radar (SAR) imagers are active microwave sensors that could overcome many challenges of passive optical bathymetry inversion, yet their capacity to yield accurate high-resolution bathymetric mapping is not studied sufficiently. In this study, we evaluate the feasibility of applying fast Fourier transform (FFT) to SAR data in coastal nearshore bathymetry derivation in Florida’s coastal waters. The study aims to develop a robust SAR bathymetry inversion framework across extensive spatial scales to address the dearth of bathymetric data in deeper nearshore coastal regions. By leveraging the Sentinel-1 datasets as a rich source of training data, our method yields high-resolution and accurate depth extraction up to 80 m. A comprehensive workflow to determine both the wavelength and peak wave period is associated with the proposed automated model compilation. A novel contour geometry-based spectral analysis technique for wavelength retrieval is presented that enables an efficient and scalable SAR bathymetry model. Multi-date SAR images were used to assess the robustness of the proposed depth-retrieval model. An accuracy assessment against the GMRT data demonstrated the high efficacy of the proposed approach, achieving a coefficient of determination (R2) above 0.95, a root-mean-square error (RMSE) of 1.56–10.20 m, and relative errors of 3.56–11.08% in automatically extracting the underwater terrain at every 50 m interval. A sensitivity analysis was conducted to estimate the uncertainty associated with our method. Overall, this study highlights the potential of SAR technology to produce updated, cost-effective, and accurate bathymetry maps of high resolution and to fill bathymetric data gaps worldwide. The code and datasets are made publicly available.
27
Tang, K. K. W., M. R. Mahmud, A. Hussaini, and A. G. Abubakar. "EVALUATING IMAGERY-DERIVED BATHYMETRY OF SEABED TOPOGRAPHY TO SUPPORT MARINE CADASTRE." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W16 (October 1, 2019): 633–39. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w16-633-2019.
Full textAbstract:
Abstract. The Department of Survey and Mapping Malaysia has introduced marine cadastre system to register the rights, other valid interests therein and ownership of spatially determined parcels in the context of the marine environment yet the implementation of the system is still at the rudimentary stage. One of the big issues here is gathering land-to-seabed data to create a seamless topographic base map to support its marine cadastre project. Seabed bathymetric mapping in coastal zone is one of the major components to support marine cadastre. In the past, accurate bathymetric measurements can be a very laborious task in hydrographic surveying. Traditional vessel-based acoustic soundings require a lot of time, operation cost and others. Today, human’s ingenuity to yield bathymetric depths from multispectral images as an alternative source to chart the seabed topography has brought in new revolution to hydrography. The paper is initiated for evaluating water depth determination by using imagery-derived bathymetry technique and check its correlation with in-situ bathymetry depths. In the course of experiment, it demonstrates a good correlation between the imagery-derived bathymetric depths and the in-situ bathymetric depths, and majority of the derived depths have passed the minimum requirement of the IHO S-44 survey standard. The result also shows that these empirical models deliver promising outcome which can be use over the turbid environment setting. Hence, imagery-derived bathymetry approach can be an efficient and repeatable way to derive the seabed topography over a huge segment of coastal region. This study also suggests that imagery-derived bathymetry approach can be recognised as an aid in seabed topographic mapping to support marine cadastre initiative.
28
Ochałek, Agnieszka, Tomasz Lipecki, Wojciech Jaśkowski, and Mateusz Jabłoński. "Modeling and Analysis of Integrated Bathymetric and Geodetic Data for Inventory Surveys of Mining Water Reservoirs." E3S Web of Conferences 35 (2018): 04005. http://dx.doi.org/10.1051/e3sconf/20183504005.
Full textAbstract:
The significant part of the hydrography is bathymetry, which is the empirical part of it. Bathymetry is the study of underwater depth of waterways and reservoirs, and graphic presentation of measured data in form of bathymetric maps, cross-sections and three-dimensional bottom models. The bathymetric measurements are based on using Global Positioning System and devices for hydrographic measurements – an echo sounder and a side sonar scanner. In this research authors focused on introducing the case of obtaining and processing the bathymetrical data, building numerical bottom models of two post-mining reclaimed water reservoirs: Dwudniaki Lake in Wierzchosławice and flooded quarry in Zabierzów. The report includes also analysing data from still operating mining water reservoirs located in Poland to depict how bathymetry can be used in mining industry. The significant issue is an integration of bathymetrical data and geodetic data from tachymetry, terrestrial laser scanning measurements.
29
Drakopoulou, Paraskevi, Ioannis P. Panagiotopoulos, Marcello de Michele, Vassilios Kapsimalis, Daniel Raucoules, Michael Foumelis, Ioannis Morfis, Isidoros Livanos, Dimitris Sakellariou, and Dimitrios Vandarakis. "Cross-Comparison of the “BathySent” Coastal Bathymetry to Sonar Measurements and Ratio Model Technique: Pilot Sites in the Aegean Sea (Greece)." Water 15, no. 18 (September 5, 2023): 3168. http://dx.doi.org/10.3390/w15183168.
Full textAbstract:
The proposed novel “BathySent” approach for coastal bathymetric mapping, using the Copernicus Sentinel-2 mission, as well as the assessment and specification of the uncertainties of the derived depth results, are the objectives of this research effort. For this reason, Sentinel-2 bathymetry retrieval results for three different pilot sites in Greece (islands of Kos, Kasos, and Crete) were compared with ground-truth data. These data comprised high-resolution swath bathymetry measurements, single-beam echosounder measurements at very shallow waters (1–10 m), and the EMODnet DTM 2018 release. The synthetic tests showed that the “BathySent” approach could restitute bathymetry in the range of 5–14 m depth, showing a standard deviation of 2 m with respect to the sonar-based bathymetry. In addition, a comparison with the “ratio model” multispectral technique was performed. The absolute differences between conventional Earth Observation-based bathymetry retrieval approaches (i.e., linear ratio model) and the suggested innovative solution, using the Sentinel-2 data, were mainly lower than 2 m. According to the outcome evaluation, both models were considered to provide results that are more reliable within the depth zone of 5–25 m. The “ratio model” technique exhibits a saturation at ~25 m depth and demands ground calibration. Though, the “BathySent” method provides bathymetric data at a lower spatial resolution compared to the “ratio model” technique; however, it does not require in situ calibration and can also perform reliably deeper than 25 m.
30
Liu, Changda, Jiawei Qi, Jie Li, Qiuhua Tang, Wenxue Xu, Xinghua Zhou, and Wenjun Meng. "Accurate Refraction Correction—Assisted Bathymetric Inversion Using ICESat-2 and Multispectral Data." Remote Sensing 13, no. 21 (October 29, 2021): 4355. http://dx.doi.org/10.3390/rs13214355.
Full textAbstract:
Shallow-water depth information is essential for ship navigation and fishery farming. However, the accurate acquisition of shallow-water depth has been a challenge for marine mapping. Combining Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) bathymetry data with multispectral data, satellite-derived bathymetry is a promising solution through which to obtain bathymetric information quickly and accurately. This study proposes a photon refraction correction method considering sea-surface undulations to address errors in the underwater photons obtained by the ICESat-2. First, the instantaneous sea surface and beam emission angle are integrated to determine the sea-surface incidence angle. Next, the distance of photon propagation in water is determined using sea-surface undulation and Snell’s law. Finally, position correction is performed through geometric relationships. The corrected photons were combined with the multispectral data for bathymetric inversion, and a bathymetric map of the Yongle Atoll area was obtained. A bathymetric chart was created using the corrected photons and the multispectral data in the Yongle Atoll. Comparing the results of different refraction correction methods with the data measured shows that the refraction correction method proposed in this paper can effectively correct bathymetry errors: the root mean square error is 1.48 m and the R2 is 0.86.
31
Yang, Jian, Yue Ma, Huiying Zheng, Yuanfei Gu, Hui Zhou, and Song Li. "Analysis and Correction of Water Forward-Scattering-Induced Bathymetric Bias for Spaceborne Photon-Counting Lidar." Remote Sensing 15, no. 4 (February 8, 2023): 931. http://dx.doi.org/10.3390/rs15040931.
Full textAbstract:
The new spaceborne photon-counting lidar, i.e., ICESat-2, has shown great advantages in obtaining nearshore bathymetry at a global scale. The forward-scattering effect in the water column is one of the main error sources in airborne lidar bathymetry (ALB). However, the magnitude of the bathymetric bias for spaceborne lidars and how can we effectively correct this bias have not been evaluated and are very worthy of investigation. In this study, the forward-scattering effect on spaceborne photon-counting lidar bathymetry is quantitatively modeled and analyzed based on the semi-analytic Monte Carlo simulation method. Meanwhile, an empirical formula for correcting forward-scattering-induced bathymetric bias specific to ICESat-2 is derived. When the water depth exceeds 20 m, this bias cannot be neglected for ICESat-2 even in clear open ocean waters. In two study areas with local in situ measurements (St. Thomas and Hawaii), the bathymetric bias of ICESat-2 in deep waters (>20 m) is corrected from exceeding 50 cm to less than 13 cm using the proposed empirical formula. This study is valuable to evaluate and correct the forward-scattering-induced bias for the existing ICESat-2 and is also fundamental to optimizing the hardware parameters of a possible future photon-counting bathymetric lidar.
32
Wan, Jiaxin, and Yi Ma. "Shallow Water Bathymetry Mapping of Xinji Island Based on Multispectral Satellite Image using Deep Learning." Journal of the Indian Society of Remote Sensing 49, no. 9 (April 26, 2021): 2019–32. http://dx.doi.org/10.1007/s12524-020-01255-9.
Full textAbstract:
AbstractNearshore bathymetry is a basic parameter of the ocean, which is crucial to the research and management of coastal zones. Previous studies have demonstrated that remote sensing techniques can be employed in estimating bathymetric information. In this paper, we propose a deep belief network with data perturbation (DBN-DP) algorithm for shallow water depth inversion from high resolution multispectral data, and applying it in Xinji Island of Malacca Strait and Yongxing Island in China. Results show that the DBN-DP method can produce more accurate water depth estimations than other traditional methods particularly for deeper water, which reaches 1.2 m of mean absolute error (MAE) and 12.8% of mean relative error (MRE) in Xinji Island. Most of the estimated bathymetry meet the category of zone of confidence C level defined by the International Hydrographic Organization. These findings are encouraging for employing deep learning in bathymetry, which may become a novel approach for bathymetric inversion in the future.
33
Brown, Michael G., Frederick D. Tappert, and Sekhar E. R. B. Sundaram. "Chaos in small-amplitude surface gravity waves over slowly varying bathymetry." Journal of Fluid Mechanics 227 (June 1991): 35–46. http://dx.doi.org/10.1017/s0022112091000022.
Full textAbstract:
We consider the motion of small-amplitude surface gravity waves over variable bathymetry. Although the governing equations of motion are linear, for general bathymetric variations they are non-separable and cannot be solved exactly. For slowly varying bathymetry, however, approximate solutions based on geometric (ray) techniques may be used. The ray equations are a set of coupled nonlinear ordinary differential equations with Hamiltonian form. It is argued that for general bathymetric variations, solutions to these equations - ray trajectories - should exhibit chaotic motion, i.e. extreme sensitivity to initial and environmental conditions. These ideas are illustrated using a simple model of bottom bathymetry, h(x,y) = h0(1 + εcos (2πx/L) cos (2πy/L)). The expectation of chaotic ray trajectories is confirmed via the construction of Poincaré sections and the calculation of Lyapunov exponents. The complexity of chaotic geometric wavefields is illustrated by considering the temporal evolution of (mostly) chaotic wavecrests. Some practical implications of chaotic ray trajectories are discussed.
34
Setiawan, Kuncoro Teguh, Syifa Wismayati Adawiah, Takahiro OSAWA, and I. Wayan Nuarsa. "APPLICATION OF VAN HENGEL AND SPITZER ALGORITHM FOR INFORMATION ON BATHYMETRY EXTRACTION USING LANDSAT DATA." International Journal of Remote Sensing and Earth Sciences (IJReSES) 11, no. 1 (April 12, 2017): 73. http://dx.doi.org/10.30536/j.ijreses.2014.v11.a2603.
Full textAbstract:
Remote sensing technology provides an opportunity for effective and efficient bathymetry mapping, especially in areas which level of depth changes quickly. Bathymetry information is very useful for hydrographic and shipping safety. Landsat medium resolution satellite imagery can be used for the extraction of bathymetry information. This study aims to extract information from the Landsat bathymetry by using Van Hengel and Spitzer rotation algorithm transformation (1991) in the water of Menjangan Island, Bali. This study shows that Van Hengel and Spitzer rotation algorithm transformation (1991) can be used to extract information on the bathymetry of Menjangan Island. Extraction of bathymetric information generated from Landsat TM imagery data in March 19, 1997 had shown the depth interval of (-0.6) m to (-12.3) m and R2 value of 0.671. While Data LANDSAT ETM + dated June 23, 2000 resulted in depth interval of 0 m to (-19.1) m and R2 value of 0.796. Furthermore, data LANDSAT ETM + dated March 12, 2003 resulted in depth interval of 0 m to (-22.5) m and R2 value of 0.931.
35
KHAKHIM, Nurul, Agung KURNIAWAN, Pramaditya WICAKSONO, and Ahmad HASRUL. "Rapid Bathymetry Mapping Based on Shallow Water Cloud Computing in Small Bay Waters: Pilot Project in Pacitan-Indonesia." Journal of Environmental Management and Tourism 15, no. 1 (February 29, 2024): 41. http://dx.doi.org/10.14505/jemt.v15.1(73).04.
Full textAbstract:
Mapping coastal areas generally requires large data constellations in time series and requires analysis using complex mathematical and modeling approaches. In shallow-water bathymetric mapping, remote sensing plays an important role in supporting conventional bathymetric mapping, especially in areas that are difficult to access. This method called Satellite Derived Bathymetry (SDB). The cloud computing approach is a solution for mapping shallow water bathymetry rapid and effectively. This study using Google Earth Engine (GEE) to compute remote sensing data for produce near-shore bathymetry. The method of Li et al. (2021) performs bathymetric extraction without using depth samples but uses chlorophyll-A as input for depth extraction parameter calculations. This study examines a small bay in the waters of Pacitan, Anakan Bay, and the waters of Kemujan Island in the Karimunjawa Islands. Within this study area, significant differences in resulting depth are very limited, ranging from 0 to -17.8. The developed model, based on the algorithm proposed by Li et al. (2021), is estimated to be able to provide accurate predictions of up to around 90% in the waters studied, with a root mean error rate (RMSE) of 1.1 meters.
36
Rossi, Lorenzo, Irene Mammi, and Filippo Pelliccia. "UAV-Derived Multispectral Bathymetry." Remote Sensing 12, no. 23 (November 27, 2020): 3897. http://dx.doi.org/10.3390/rs12233897.
Full textAbstract:
Bathymetry is considered an important component in marine applications as several coastal erosion monitoring and engineering projects are carried out in this field. It is traditionally acquired via shipboard echo sounding, but nowadays, multispectral satellite imagery is also commonly applied using different remote sensing-based algorithms. Satellite-Derived Bathymetry (SDB) relates the surface reflectance of shallow coastal waters to the depth of the water column. The present study shows the results of the application of Stumpf and Lyzenga algorithms to derive the bathymetry for a small area using an Unmanned Aerial Vehicle (UAV), also known as a drone, equipped with a multispectral camera acquiring images in the same WorldView-2 satellite sensor spectral bands. A hydrographic Multibeam Echosounder survey was performed in the same period in order to validate the method’s results and accuracy. The study area was approximately 0.5 km2 and located in Tuscany (Italy). Because of the high percentage of water in the images, a new methodology was also implemented for producing a georeferenced orthophoto mosaic. UAV multispectral images were processed to retrieve bathymetric data for testing different band combinations and evaluating the accuracy as a function of the density and quantity of sea bottom control points. Our results indicate that UAV-Derived Bathymetry (UDB) permits an accuracy of about 20 cm to be obtained in bathymetric mapping in shallow waters, minimizing operative expenses and giving the possibility to program a coastal monitoring surveying activity. The full sea bottom coverage obtained using this methodology permits detailed Digital Elevation Models (DEMs) comparable to a Multibeam Echosounder survey, and can also be applied in very shallow waters, where the traditional hydrographic approach requires hard fieldwork and presents operational limits.
37
Scheick, Jessica, Ellyn Enderlin, Emily Miller, and Gordon Hamilton. "First-Order Estimates of Coastal Bathymetry in Ilulissat and Naajarsuit Fjords, Greenland, from Remotely Sensed Iceberg Observations." Remote Sensing 11, no. 8 (April 18, 2019): 935. http://dx.doi.org/10.3390/rs11080935.
Full textAbstract:
Warm water masses circulating at depth off the coast of Greenland play an important role in controlling rates of mass loss from the Greenland Ice Sheet through feedbacks associated with the melting of marine glacier termini. The ability of these warm waters to reach glacier termini is strongly controlled by fjord bathymetry, which was unmapped for the majority of Greenland’s fjords until recently. In response to the need for bathymetric measurements in previously uncharted areas, we developed two companion methods to infer fjord bathymetry using icebergs as depth sounders. The main premise of our methods centers around the idea that deep-drafted icebergs will become stranded in shallow water such that estimates of iceberg surface elevation can be used to infer draft, and thus water depth, under the assumption of hydrostatic equilibrium. When and where available, surface elevations of icebergs stranded on bathymetric highs were extracted from digital elevation models (DEMs) and converted to estimates of iceberg draft. To expand the spatial coverage of our inferred water depths beyond the DEM footprints, we used the DEMs to construct characteristic depth–width ratios and then inferred depths from satellite imagery-derived iceberg widths. We tested and applied the methods in two fjord systems in western Greenland with partially constrained bathymetry, Ilulissat Isfjord and Naajarsuit Fjord, to demonstrate their utility for inferring bathymetry using remote sensing datasets. Our results show that while the uncertainties associated with the methods are high (up to ±93 m), they provide critical first-order constraints on fjord bathymetry.
38
Zhang, Zhenrui, Chen Feng, and Yuxuan Zhang. "Research on Multibeam Bathymetric System Based on Geometrical Relation Mo Model." Academic Journal of Science and Technology 8, no. 1 (November 21, 2023): 100–103. http://dx.doi.org/10.54097/ajst.v8i1.14004.
Full textAbstract:
In this paper, the basic principles of multibeam bathymetry system are discussed in depth, the development of which originates from the single-beam bathymetry technology. Through profound mathematical modelling and geometric relationship derivation, a systematic and detailed analysis is carried out for the coverage width of multibeam bathymetry and the overlap rate between two adjacent bands in the case that the survey line is parallel to the horizontal plane. Adopting the idea of combining numbers and shapes, combined with the triangle side angle relationship, we established a geometrical-mathematical model with an α-slope slant line, which lays a solid theoretical foundation for solving the problem. In this study, we successfully solved the expression of seawater depth D of the multibeam bathymetric system in the case that the direction of the survey line is parallel to the horizontal plane by the method of listing relations. At the same time, we make full use of the sine-cosine theorem of triangles to derive the coverage width of the bathymetric strip in depth. Combining these two organically, a complete and detailed expression for the coverage width is formed, which provides a powerful mathematical tool for the further study of deep-sea bathymetry technology. In addition, by applying the mathematical model to the vacant data in Table 1, we successfully fill in this missing information, demonstrating the feasibility and accuracy of the model in practical applications. This study not only makes remarkable progress in theory, but also provides strong support for practical applications in the field of ocean bathymetry.
39
Williams, Christopher N., Stephen L. Cornford, Thomas M. Jordan, Julian A. Dowdeswell, Martin J. Siegert, Christopher D. Clark, Darrel A. Swift, Andrew Sole, Ian Fenty, and Jonathan L. Bamber. "Generating synthetic fjord bathymetry for coastal Greenland." Cryosphere 11, no. 1 (February 1, 2017): 363–80. http://dx.doi.org/10.5194/tc-11-363-2017.
Full textAbstract:
Abstract. Bed topography is a critical boundary for the numerical modelling of ice sheets and ice–ocean interactions. A persistent issue with existing topography products for the bed of the Greenland Ice Sheet and surrounding sea floor is the poor representation of coastal bathymetry, especially in regions of floating ice and near the grounding line. Sparse data coverage, and the resultant coarse resolution at the ice–ocean boundary, poses issues in our ability to model ice flow advance and retreat from the present position. In addition, as fjord bathymetry is known to exert strong control on ocean circulation and ice–ocean forcing, the lack of bed data leads to an inability to model these processes adequately. Since the release of the last complete Greenland bed topography–bathymetry product, new observational bathymetry data have become available. These data can be used to constrain bathymetry, but many fjords remain completely unsampled and therefore poorly resolved. Here, as part of the development of the next generation of Greenland bed topography products, we present a new method for constraining the bathymetry of fjord systems in regions where data coverage is sparse. For these cases, we generate synthetic fjord geometries using a method conditioned by surveys of terrestrial glacial valleys as well as existing sinuous feature interpolation schemes. Our approach enables the capture of the general bathymetry profile of a fjord in north-west Greenland close to Cape York, when compared to observational data. We validate our synthetic approach by demonstrating reduced overestimation of depths compared to past attempts to constrain fjord bathymetry. We also present an analysis of the spectral characteristics of fjord centrelines using recently acquired bathymetric observations, demonstrating how a stochastic model of fjord bathymetry could be parameterised and used to create different realisations.
40
Gao, Jay. "Bathymetric mapping by means of remote sensing: methods, accuracy and limitations." Progress in Physical Geography: Earth and Environment 33, no. 1 (February 2009): 103–16. http://dx.doi.org/10.1177/0309133309105657.
Full textAbstract:
Bathymetry has been traditionally charted via shipboard echo sounding. Alhough able to generate accurate depth measurements at points or along transects, this method is constrained by its high operating cost, inefficiency, and inapplicability to shallow waters. By comparison, remote sensing methods offer more flexible, efficient and cost-effective means of mapping bathymetry over broad areas. Remote sensing of bathymetry falls into two broad categories: non-imaging and imaging methods. The non-imaging method (as typified by LiDAR) is able to produce accurate bathymetric information over clear waters at a depth up to 70 m. However, this method is limited by the coarse bathymetric sampling interval and high cost. The imaging method can be implemented either analytically or empirically, or by a combination of both. Analytical or semi-analytical implementation is based on the manner of light transmission in water. It requires inputs of a number of parameters related to the properties of the atmosphere, water column, and bottom material. Thus, it is rather complex and difficult to use. By comparison, empirical implementation is much simpler and requires the input of fewer parameters. Both implementations can produce fine-detailed bathymetric maps over extensive turbid coastal and inland lake waters quickly, even though concurrent depth samples are essential. The detectable depth is usually limited to 20 m. The accuracy of the retrieved bathymetry varies with water depth, with the accuracy substantially lower at a depth beyond 12 m. Other influential factors include water turbidity and bottom materials, as well as image properties.
41
Wang, Yitong, Ziyi Lu, Dihao Ma, and Zixin Yang. "The study of the direction of navigation of ships in a particular sea area." Highlights in Science, Engineering and Technology 82 (January 26, 2024): 77–84. http://dx.doi.org/10.54097/fq9fg659.
Full textAbstract:
Multibeam bathymetric system is a further development of single-beam bathymetric system, which can send and receive hundreds of beams at the same time during the working process, and carry out full-coverage bathymetric strip measurements in the smooth sea area on the seabed. In this paper, we model the coverage width and the overlap rate to further reduce the errors occurring in the measurement process, and at the same time, we design a scheme for the given data and constraints to solve the practical problems. The process analysis facilitates the practical application of multibeam bathymetry system, improves the problems of failing to achieve the full coverage of the sea area and the high overlap rate, and provides a new idea for the seabed detection of multibeam bathymetry.
42
Rahmawan, Guntur Adhi, Semeidi Husrin, and Joko Prihantono. "BATHYMETRY CHANGES ANALYSIS IN SERANG DISTRICT WATERS CAUSED BY SEABED SAND EXPLOITATION." Jurnal Ilmu dan Teknologi Kelautan Tropis 9, no. 1 (November 2, 2017): 45–55. http://dx.doi.org/10.29244/jitkt.v9i1.17916.
Full textAbstract:
Morphological changes. i.e. shoreline change and bathymetry change of Serang District were significantly influence by natural factors as well as human activities of sand mining (seabed sand exploitation). Bathymetric data were obtained through direct bathymetry measurements using Single-Beam Echosounder (Echotrac CVM Teledyne Odom Hydrographic) and GPS- Real Time Kinematic (RTK) as well as through secondary data from digitization data of DISHIDROS and LPI BIG. The data obtained is then processed to obtain the volume of moved bed sediment using 2 different topography overlays, from the bathymetry analysis result, we obtained the volume of natural sediment transported is 95,800 m3 with the value of average thickness is 0.036 m. therefore, the volume which is caused by human factors (sand mining activities during 2003-2013) is 5,578,470 m3 with the sand mining area extents of 261.9 Ha. Resulting the small basin with 2.13 m depth. Keywords: bathymetry, lontar village, morphology, sand mining, coastal zone
43
Guo, Qiang, Chuanyu Fu, Yikang Chen, and Yu Zhang. "Application of multi-beam bathymetry system in shallow water area." Journal of Physics: Conference Series 2428, no. 1 (February 1, 2023): 012042. http://dx.doi.org/10.1088/1742-6596/2428/1/012042.
Full textAbstract:
Abstract Multi-beam bathymetry technology plays an important role in ocean, river and lake surveying and mapping. According to the measurement principle and technical requirements of MS8200 multi-beam bathymetry system, this paper introduces the composition and working principle of the system, the installation and calibration of the system, and the data in the post-processing process, the sea area and terrain characteristics near Wenchang Qinglan Port are taken as the research object to discuss the dual multi-beam bathymetric technology and data processing process, and compare the data of single multi-beam in the same sea area. The research results show that the dual probe of multibeam bathymetry system can better reflect the topographic features of the seafloor compared with the single probe, and shorten the time of mapping, reduce the labor intensity and improve the measurement efficiency, and provide data reference for the stability and reliability evaluation study of the dual probe of multibeam bathymetry system.
44
Li, Qianqian, Zhenhe Zhai, Qi Li, Lin Wu, Lifeng Bao, and Heping Sun. "Improved Bathymetry in the South China Sea from Multisource Gravity Field Elements Using Fully Connected Neural Network." Journal of Marine Science and Engineering 11, no. 7 (June 30, 2023): 1345. http://dx.doi.org/10.3390/jmse11071345.
Full textAbstract:
Traditional bathymetry inversion methods that rely on an altimetry-derived gravity anomaly (GA) and/or a vertical gravity gradient anomaly (VGG) have been widely used for bathymetry prediction in the South China Sea. However, few studies attempt new methods to combine multisource gravity data to improve the accuracy of the bathymetry. In this study, we introduce a fully connected deep neural network (FC-DNN) to merge GA, VGG, and the deflection of vertical (DOV) to predict the bathymetry in the South China Sea. Single beam sounding depths were used as sample data for neural network training. Independent shipboard depths and GEBCO2023, topo_25.1, and ETOPO2022 models were applied as validation data. The assessment results showed that the FC-DNN model reached a high precision level with an STD of 49.20 m. More than 70% of the differences between the FC-DNN bathymetric model and other depth models were less than 100 m. Furthermore, the spectral analysis results showed that the FC-DNN bathymetry model has stronger energy in medium and short wavelengths than other models, which indicates that additional gravity field element DOVs can recover richer topographic signals in those particular bands.
45
Sesama, Asih Sekar, Kuncoro Teguh Setiawan, and Atriyon Julzarika. "BATHYMETRIC EXTRACTION USING PLANETSCOPE IMAGERY (CASE STUDY: KEMUJAN ISLAND, CENTRAL JAVA)." International Journal of Remote Sensing and Earth Sciences (IJReSES) 17, no. 2 (March 24, 2021): 209. http://dx.doi.org/10.30536/j.ijreses.2020.v17.a3445.
Full textAbstract:
Bathymetry refers to the depth of the seabed relative to the lowest water level. Depth information is essential for various studies of marine resource activities, for managing port facilities and facilities, supporting dredging operations, and predicting the flow of sediment from rivers into the sea. Bathymetric mapping using remote sensing offers a more flexible, efficient,and cost-effective method and covers a largearea. This study aims to determine the ability of Planet Scope imagery to estimate and map bathymetry and to as certain its accuracy using the Stumpf algorithm on the in-situ depth data. PlanetScope level 3B satellite imagery and tide-corrected survey dataare employed; satellite images are useful in high-precision bathymetry extraction.The bathymetric extraction method used the Stumpf algorithm. The research location was Kemujan Island, Karimunjawa Islands, Central Java. The selection of this region wasbased on its water characteristics, which have a reasonably high variation in depth. Based on the results of the data processing, it was found that the PlanetScope image data were able to estimate depths of up to 20 m. In the bathymetric results, the R2 accuracy value was 0.6952, the average RMSE value was 2.85 m,and the overall accuracy rate was 71.68%.
46
Hasan, Md Abid, Rafid Fayyaz, Mahfujur Rahman, Mahmudul Hasan, Md Atikul Islam, and Shamiha Shafinaz Shreya. "ESTIMATION OF SHALLOW WATER BATHYMETRY ALONG THE NORTHERN COAST OF BAY OF BENGAL: A REMOTE SENSING-BASED APPROACH." Malaysian Journal of Geosciences 7, no. 2 (March 31, 2023): 173–79. http://dx.doi.org/10.26480/mjg.02.2023.173.179.
Full textAbstract:
Bathymetric information is vital for navigational safety and is utilized for many more activities. Remote sensing data and satellite images are widely used these days to determine shallow coastal areas’ bathymetry at a low cost. This study reviewed different methods for satellite-derived bathymetry and selected the ratio transform method to apply to Landsat 8 imagery. Two images covered the northern coastal region of the Bay of Bengal. They were processed using a ratio-based algorithm calibrated with reference data. A hydrographic chart from the Bangladesh Navy depicted a general overview of the study area. Another chart from the BIWTA, along with GEBCO gridded bathymetry data, was used as reference data for the study. The ArcGIS and ENVI image processing software was used to process and analyze satellite imagery. The correlation between the satellite-derived bathymetry and reference data was also studied at the end of the study. The mean absolute deviation, mean squared error, and root mean square error were also evaluated. Both algorithms were able to extract bathymetry up to a depth of 12 meters with minimal errors. Satellite Derived Bathymetry (SDB) from the Central Coast resulted in an R-squared value of 0.82 with a Mean Absolute Deviation (MAD) of 0.89. SDB from the Western Coast had R2 of 0.81 and MAD of 1.16. After interpolating the algorithm results, contour lines were also generated to visualize the bathymetry. The deviations and irregularities in the contours resulted due to the high turbidity of the coastal waters of the Bay of Bengal.
47
Wijesundara, Anusha, and R. M. D. I. Rathnayake. "Automated Estimation of Coastal Bathymetry from High Resolution Multi-Spectral Satellite Images." European Journal of Engineering Research and Science 4, no. 11 (November 29, 2019): 74–81. http://dx.doi.org/10.24018/ejers.2019.4.11.1600.
Full textAbstract:
Coastal bathymetry is the most essential tool for marine planning, monitoring and management, modelling, nautical navigation and scientific studies of marine environments. The techniques have been developed over the last decade to derive bathymetry using remote sensing technology with efficiently and low costly. Log linear bathymetric inversion model and non-linear bathymetric inversion model provides two empirical approaches for deriving bathymetry from multispectral satellite imagery, which have been refined and widely applied. This paper compares these two approaches by means of a geographical error analysis for the site Kankesanturai using WorldView-2 satellite imagery. In order to calibrate both models; Single Beam Echo Sounding (SBES) data in this study area were used as reference points. Corrections for atmospheric and sun-glint effects are applied prior to the water depth algorithm. The algorithm was tuned and both models were calibrated by performing the necessary algorithm with available single beam echo sounding data in the study area. The coefficients of standard R2 is estimated as 0.846 for log-linear and 0.692 for non-linear model. Log linear model performs better than the non-linear model. The model residuals were mapped and the spatial auto-correlation was calculated based on the bathymetric estimation model. A spatial error model was constructed to generate more reliable estimates of bathymetry by calculating the spatial autocorrelation of model error and integrating this into an improved regression model. Finally, the spatial error model improved the bathymetric estimates of R2 up to 0.854 for log-linear and 0.704 non-linear model respectively. The Root Mean Square Error (RMSE) was calculated for the different depth ranges and also for all reference points. The overall accuracy for the log linear and the non-linear inversion model after the geographical error analysis is estimated as ±1.532 m and ±2.089 m for this study. The spatial error model improved bathymetric estimates than those derived from a conventional log-linear and non-linear technique although these methods perform very similar estimates overall.
48
Wijesundara, Anusha, and R. M. D. I. Rathnayake. "Automated Estimation of Coastal Bathymetry from High Resolution Multi-Spectral Satellite Images." European Journal of Engineering and Technology Research 4, no. 11 (November 29, 2019): 74–81. http://dx.doi.org/10.24018/ejeng.2019.4.11.1600.
Full textAbstract:
Coastal bathymetry is the most essential tool for marine planning, monitoring and management, modelling, nautical navigation and scientific studies of marine environments. The techniques have been developed over the last decade to derive bathymetry using remote sensing technology with efficiently and low costly. Log linear bathymetric inversion model and non-linear bathymetric inversion model provides two empirical approaches for deriving bathymetry from multispectral satellite imagery, which have been refined and widely applied. This paper compares these two approaches by means of a geographical error analysis for the site Kankesanturai using WorldView-2 satellite imagery. In order to calibrate both models; Single Beam Echo Sounding (SBES) data in this study area were used as reference points. Corrections for atmospheric and sun-glint effects are applied prior to the water depth algorithm. The algorithm was tuned and both models were calibrated by performing the necessary algorithm with available single beam echo sounding data in the study area. The coefficients of standard R2 is estimated as 0.846 for log-linear and 0.692 for non-linear model. Log linear model performs better than the non-linear model. The model residuals were mapped and the spatial auto-correlation was calculated based on the bathymetric estimation model. A spatial error model was constructed to generate more reliable estimates of bathymetry by calculating the spatial autocorrelation of model error and integrating this into an improved regression model. Finally, the spatial error model improved the bathymetric estimates of R2 up to 0.854 for log-linear and 0.704 non-linear model respectively. The Root Mean Square Error (RMSE) was calculated for the different depth ranges and also for all reference points. The overall accuracy for the log linear and the non-linear inversion model after the geographical error analysis is estimated as ±1.532 m and ±2.089 m for this study. The spatial error model improved bathymetric estimates than those derived from a conventional log-linear and non-linear technique although these methods perform very similar estimates overall.
49
Lv, Jinhao, Shaoyu Li, Xiaoming Wang, Chao Qi, and Meng Zhang. "Long-term Satellite-derived Bathymetry of Arctic Supraglacial Lake from ICESat-2 and Sentinel-2." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-1-2024 (May 10, 2024): 469–77. http://dx.doi.org/10.5194/isprs-archives-xlviii-1-2024-469-2024.
Full textAbstract:
Abstract. The polar ice sheets serve as natural thermostats, regulating Earth’s temperatures. The Greenland Ice Sheet (GrIS), the second-largest ice sheet, is a critical indicator of climate change and global warming. Estimating the volume of supraglacial lakes on the GrIS, which is directly linked to the extent of melting in the Arctic ice sheet, requires information on both lake area and water depth. Conventional bathymetric methods (i.e., airborne bathymetric LiDAR, shipborne echo-sounder) are commonly used for accurate water depth measurement. However, polar supraglacial lakes face challenging conditions, leading to uncertainties in their spatial and temporal distribution. To overcome the limitations, this study combines Sentinel-2 and ICESat-2 (Ice, Cloud, and Land Elevation Satellite-2) to estimate bathymetry and detect changes in lake volume on the GrIS from 2019 to 2023. Firstly, Sentinel-2 images were pre-processed, and ICESat-2 single-photon LiDAR points were extracted using the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) method, followed by the bathymetric corrections as the training data. Subsequently, three bathymetry models (i.e., log-linear, log-ratio, and BP (Back Propagation) neural network) were constructed using Sentinel-2 images and ICESat-2 data. Lastly, the highresolution ArcticDEM (Arctic Digital Elevation Model) was used as the validation data to assess the satellite-derived bathymetry accuracy. In this study, the log-ratio model yielded the best results with the R2, RMSE, and MAE of 0.92, 0.79 m (lower than 10% of the maximum depth), and 0.62 m. The results demonstrate the feasibility of the integrated active and passive remote sensing approach for bathymetry in Arctic supraglacial lakes.
50
Copping, Joshua P., Bryce D. Stewart, Colin J. McClean, James Hancock, and Richard Rees. "Does bathymetry drive coastal whale shark (Rhincodon typus)aggregations?" PeerJ 6 (June 8, 2018): e4904. http://dx.doi.org/10.7717/peerj.4904.
Full textAbstract:
BackgroundThe whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations forR. typusthrough bathymetry’s effect on primary productivity and prey availability. This is a global study taking into account all coastal areas withinR. typus’range.MethodsR. typusaggregation locations were identified through an extensive literature review. Global bathymetric data were compared atR. typusaggregation locations and a large random selection of non-aggregation areas. Generalised linear models were used to assess which bathymetric characteristic had the biggest influence on aggregation presence.ResultsAggregation sites were significantly shallower than non-aggregation sites and in closer proximity to deep water (the mesopelagic zone) by two orders of magnitude. Slope at aggregation sites was significantly steeper than non-aggregation sites. These three bathymetric variables were shown to have the biggest association with aggregation sites, with up to 88% of deviation explained by the GLMs.DiscussionThe three key bathymetric characteristics similar at the aggregation sites are known to induce upwelling events, increase primary productivity and consequently attract numerous other filter feeding species. The location of aggregation sites in these key areas can be attributed to this increased prey availability, thought to be the main reasonR. typusaggregations occur, extensively outlined in the literature. The proximity of aggregations to shallow areas such as reefs could also be an important factor why whale sharks thermoregulate after deep dives to feed. These findings increase our understanding of whale shark behaviour and may help guide the identification and conservation of further aggregation sites.