Submit to Sensors Review for Sensors Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Advanced Sensing Technology for Ocean Observation

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Remote Sensors".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 28555

Share This Special Issue

Special Issue Editor

Dr. Federico Angelini

E-Mail Website
Guest Editor

ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Frascati, Italy
Interests: remote sensing; lidar; fluorescence spectroscopy; reflectance spectroscopy; Raman spectroscopy; eye safe remote sensing; reflectance and colorimetry

Special Issue Information

Dear Colleagues,

As you know, oceans play a key role in determining climate and life on the earth. In spite of their importance, however, many aspects of sea science are still rather unknown, both because of the complexity of interactions between physics, chemistry, biology, and human activities and because of the difficulties to carry out accurate, continuous, and reliable measurements even of simple variables such as temperature and salinity. Many kinds of measurements, in particular by satellite, offer great advantages in terms of coverage and continuity but suffer some important drawbacks that cannot be overcome through other satellite observations (e.g., vertical profiles in water are inaccessible by remote sensing because of the strong absorption of electromagnetic waves by water).

Many open problems, spanning different spatial scales (from molecular processes to global issues) and timescales (from chemical dynamics to geological eras) still limit our understanding of the processes that involve ocean physics, chemistry, and biology. There is a new challenge for accurate, reliable, and continuous measurements in a variety of fields, from basic physics to applications for optimization and sustainability of fishing and navigation. This Special Issue aims to gather valuable and innovative papers on (but not exclusively) the following subjects:

Ocean sensor networks

- Optical

- Chemical

- Dynamics

- Data management of sensor networks

Ocean remote sensing

- Satellite and airborne sensors

- Acoustic sensing

- Sensors for bathymetry

Ocean in situ observations

- Surface and deep-sea measurements

- Automated stations

- Drifters and AUVs

- Ship-of-opportunity missions

Sensors for ocean physics

- Temperature

- Density and Salinity

- Turbulence

- Sound

- Waves

- Marine spectroscopy (fluorescence, Raman, absorption, ocean color, among others)

Sensors for ocean chemistry

-CO2, methane, hydrogen, hydrogen sulfide balance.

- Radon

- pH and ocean acidification

- Trace metals (lead, cadmium, copper, mercury etc.)

- Plastics and microplastics

- Dissolved gases

Sensors for ocean biology

- Automated recognition of marine organisms

- Sensing of nutrients and trophic levels

- Sensors for species tracking and control

Marine sensor technology characterization and validation

- Innovative techniques for classic measurements

- Calibration and comparison of sensors with certified procedures and instruments.

Dr. Federico Angelini
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (10 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Other

14 pages, 3411 KiB

Open AccessArticle

A New Acoustical Autonomous Method for Identifying Endangered Whale Calls: A Case Study of Blue Whale and Fin Whale

by Farook Sattar

Sensors 2023, 23(6), 3048; https://doi.org/10.3390/s23063048 - 12 Mar 2023

Cited by 4 | Viewed by 2680

Abstract

In this paper, we study to improve acoustical methods to identify endangered whale calls with emphasis on the blue whale (Balaenoptera musculus) and fin whale (Balaenoptera physalus). A promising method using wavelet scattering transform and deep learning is proposed here to detect/classify the whale calls quite precisely in the increasingly noisy ocean with a small dataset. The performances shown in terms of classification accuracy (>97%) demonstrate the efficiency of the proposed method which outperforms the relevant state-of-the-art methods. In this way, passive acoustic technology can be enhanced to monitor endangered whale calls. Efficient tracking of their numbers, migration paths and habitat become vital to whale conservation by lowering the number of preventable injuries and deaths while making progress in their recovery. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

14 pages, 7347 KiB

Open AccessArticle

Microstructure Turbulence Measurement in the Northern South China Sea from a Long-Range Hybrid AUV

by Yunli Nie, Xin Luan, Yan Huang, Libin Du, Dalei Song and Xiuyan Liu

Sensors 2023, 23(4), 2014; https://doi.org/10.3390/s23042014 - 10 Feb 2023

Viewed by 1676

Abstract

This study describes the development of a long-range hybrid autonomous underwater vehicle (AUV) for ocean turbulence measurement. It is a unique instrument, combining the characteristics of the conventional AUV and the buoyancy-driven glider, with a variety of flexible motion modes, such as cruise mode, glider mode, drift mode, and combination of multiple motion modes. The hybrid AUV was used for continuous turbulence measurement in the continental slope of the northern South China Sea in 2020. A total of ten continuous profiles were completed covering a horizontal span of 25 Km and a depth of 200 m. The hybrid AUV was operated in the combined glider and cruise mode. The hybrid AUV’s flight performance was stable and satisfied the requirement for turbulence observation. The measured velocity shears from both probes were in good agreement, and the noise-reduced shear spectra were in excellent agreement with the Nasmyth spectrum. The water column in the study area was highly stratified, with a thick thermocline. The dissipation rate (ε) varied from 1.41 × 10⁻¹⁰ to 4.18 × 10⁻⁷ W·kg⁻¹. In the surface mixed layer, high values of ε (10⁻⁹∼10⁻⁸ W·kg⁻¹) were observed toward the water surface. In the thermocline, ε was 10^−9.5∼10⁻⁹ W·kg⁻¹, which was smaller than the level of the surface mixed layer. This result was mainly because of the strong “barrier”-like thermocline, which damped the transmission of wind and heat energy from the surface mixed layer to the deep layer. Overall, this study demonstrates the utility of hybrid AUVs for collecting oceanic turbulence measurements. They are a powerful addition to traditional turbulence instruments, as they make it possible to survey large areas to obtain high-quality and high-resolution data in both vertical and horizontal directions over long durations. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

12 pages, 518 KiB

Open AccessArticle

A Simple Approach to Estimate the Drag Coefficients of a Submerged Floater

by Yuval Hoffman, Liav Nagar, Ilan Shachar and Roee Diamant

Sensors 2023, 23(3), 1394; https://doi.org/10.3390/s23031394 - 26 Jan 2023

Cited by 2 | Viewed by 3502

Abstract

The calculation of the drag force is a fundamental requirement in the design of any submerged system intended for marine exploration. The calculation can be performed by analytic analysis, numerical modeling, or by a direct calculation performed in a designated testing facility. However, for complex structures and especially those with a non-rigid design, the analytic and numerical analyses are not sufficiently accurate, while the direct calculation is a costly operation. In this paper, we propose a simple approach for how to calculate the drag coefficient in-situ. Aimed specifically at the complex case of elastic objects whose modeling via Computer-Aided Design (CAD) is challenging, our approach evaluates the relation between the object’s speed at steady-state and its mass to extract the drag coefficient in any desired direction, the hydro-static force, and, when relevant, also the thruster’s force. We demonstrate our approach for the special case of a highly complex elastic-shaped floater that profiles the water column. The analysis of two such floaters in two different sea environments shows accurate evaluation results and supports our claim for robustness. In particular, the simplicity of the approach makes it appealing for any arbitrary shaped object. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

15 pages, 4969 KiB

Open AccessArticle

USV-Observed Turbulent Heat Flux Induced by Late Spring Cold Dry Air Incursion over Sub-Mesoscale Warm Regions off Sanriku, Japan

by Akira Nagano, Takuya Hasegawa, Keisuke Ariyoshi, Takeshi Iinuma, Tatsuya Fukuda, Nobuhiro Fujii, Fumiaki Tomita and Ryota Hino

Sensors 2022, 22(24), 9695; https://doi.org/10.3390/s22249695 - 10 Dec 2022

Cited by 3 | Viewed by 2104

Abstract

We performed oceanic and atmospheric observations in the region off the Sanriku coast, Japan, from May 11 to 5 July 2022, using a wave-propelled unmanned surface vehicle, a Wave Glider (WG). Despite the severe weather conditions of atmospheric low-pressure system crossings, we successfully measured wind, air temperature, humidity, and sea surface temperature over the course of 55 days to calculate the turbulent heat flux. The WG observed that the atmosphere became more humid due to the southerly wind along the northwestern rim of the North Pacific subtropical high. The warm Kuroshio water expanded to the southeast of Hokkaido as a result of the northward shedding of an anticyclonic mesoscale (

~ 100

km) eddy, called a warm-core ring, from the Kuroshio Extension. The WG traversed smaller (sub-mesoscale) water regions that were warmer and saltier than the surrounding Kuroshio water. The observations indicate that cold, dry air masses advected by northerly winds following the passage of atmospheric low-pressure systems generate a substantial upward turbulent heat flux over sub-mesoscale warm water regions, contrasting to no heat flux in the surrounding Kuroshio water region. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

25 pages, 15116 KiB

Open AccessArticle

Optimization of the NRCS Sampling at the Sea Wind Retrieval by the Airborne Rotating-Beam Scatterometer Mounted under Fuselage

by Alexey Nekrasov, Alena Khachaturian and Evgenii Vorobev

Sensors 2022, 22(11), 4016; https://doi.org/10.3390/s22114016 - 25 May 2022

Cited by 3 | Viewed by 1478

Abstract

The optimization of normalized radar cross-section (NRCS) sampling by a scatterometer allows an increase in the accuracy of the wind retrieval over the water surface and a decrease in the time of the measurement. Here, we investigate the possibility of improving wind vector measurement with an airborne rotating-beam scatterometer mounted under the fuselage. For this purpose, we investigated NRCS sampling at various incidence angles, and the possibility of using NRCS samples obtained during simultaneous measurement at different incidence angles to perform wind retrieval. The proposed wind algorithms are based on a geophysical model function (GMF). Sea wind retrieval was carried out using Monte Carlo simulations with consideration of a single incidence angle or combinations of several incidence angles. The incidence angles of interest were 30°, 35°, 40°, 45°, 50°, 55°, and 60°. The simulation showed that the wind speed error decreased with an increase in the incidence angle, and the wind direction error tended to decrease with an increase in the incidence angle. The single incidence angle case is characterized by higher maximum wind retrieval errors but allows for a higher maximum altitude of the wind retrieval method’s applicability to be achieved. The use of several neighboring incidence angles allows a better wind vector retrieval accuracy to be achieved. The combinations of three and four incidence angles provided the lowest maximum wind speed and direction errors in the range of the incidence angles from 45° to 60° but, unfortunately, provide the lowest maximum altitude of applicability of the wind retrieval method. At the same time, the combination of two incidence angles is characterized by slightly higher maximum wind retrieval errors than in the cases of three and four incidence angles, but they are lower than in the case of the single incidence angle. Moreover, the two incidence angles’ combination is a simpler way to decrease the wind retrieval errors, especially for measurement near an incidence angle of 30°, providing nearly the highest maximum altitude of the wind retrieval method applicability. The results obtained can be used to enhance existing airborne radars and in the development of new remote sensing systems. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Graphical abstract

20 pages, 6292 KiB

Open AccessArticle

Evaluation of a New Lightweight UAV-Borne Topo-Bathymetric LiDAR for Shallow Water Bathymetry and Object Detection

by Dandi Wang, Shuai Xing, Yan He, Jiayong Yu, Qing Xu and Pengcheng Li

Sensors 2022, 22(4), 1379; https://doi.org/10.3390/s22041379 - 11 Feb 2022

Cited by 40 | Viewed by 4680

Abstract

Airborne LiDAR bathymetry (ALB) has proven to be an effective technology for shallow water mapping. To collect data with a high point density, a lightweight dual-wavelength LiDAR system mounted on unmanned aerial vehicles (UAVs) was developed. This study presents and evaluates the system using the field data acquired from a flight test in Dazhou Island, China. In the precision and accuracy assessment, the local fitted planes extracted from the water surface points and the multibeam echosounder data are used as a reference for water surface and bottom measurements, respectively. For the bathymetric performance comparison, the study area is also measured with an ALB system installed on the manned aerial platform. The object detection capability of the system is examined with placed small cubes. Results show that the fitting precision of the water surface is 0.1227 m, and the absolute accuracy of the water bottom is 0.1268 m, both of which reach a decimeter level. Compared to the manned ALB system, the UAV-borne system provides higher resolution data with an average point density of 42 points/m² and maximum detectable depth of 1.7–1.9 Secchi depths. In the point cloud of the water bottom, the existence of a 1-m target cube and the rough shape of a 2-m target cube are clearly observed at a depth of 12 m. The system shows great potential for flexible shallow water mapping and underwater object detection with promising results. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

17 pages, 5183 KiB

Open AccessArticle

Estimating Water Transport from Short-Term Vessel-Based and Long-Term Bottom-Mounted Acoustic Doppler Current Profiler Measurements in an Arctic Lagoon Connected to the Beaufort Sea

by Chunyan Li and Kevin Mershon Boswell

Sensors 2022, 22(1), 68; https://doi.org/10.3390/s22010068 - 23 Dec 2021

Cited by 2 | Viewed by 3275

Abstract

Acoustic Doppler current profilers (ADCP) are quasi-remote sensing instruments widely used in oceanography to measure velocity profiles continuously. One of the applications is the quantification of land–ocean exchange, which plays a key role in the global cycling of water, heat, and materials. This exchange mostly occurs through estuaries, lagoons, and bays. Studies on the subject thus require that observations of total volume or mass transport can be achieved. Alternatively, numerical modeling is needed for the computation of transport, which, however, also requires that the model is validated properly. Since flows across an estuary, lagoon, or bay are usually non-uniform and point measurements will not be sufficient, continuous measurements across a transect are desired but cannot be performed in the long run due to budget constraints. In this paper, we use a combination of short-term transect-based measurements from a vessel-mounted ADCP and relatively long-term point measurements from a moored ADCP at the bottom to obtain regression coefficients between the transport from the vessel-based observations and the depth-averaged velocity from the bottom-based observations. The method is applied to an Arctic lagoon by using an ADCP mounted on a buoyant platform towed by a small inflatable vessel and another ADCP mounted on a bottom deployed metal frame. The vessel-based measurements were performed continuously for nearly 5 h, which was sufficient to derive a linear regression between the datasets with an R²-value of 0.89. The regression coefficients were in turn applied to the entire time for the moored instrument measurements, which are used in the interpretation of the subtidal transport variations. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

19 pages, 3660 KiB

Open AccessArticle

Correction of Biogeochemical-Argo Radiometry for Sensor Temperature-Dependence and Drift: Protocols for a Delayed-Mode Quality Control

by Quentin Jutard, Emanuele Organelli, Nathan Briggs, Xiaogang Xing, Catherine Schmechtig, Emmanuel Boss, Antoine Poteau, Edouard Leymarie, Marin Cornec, Fabrizio D’Ortenzio and Hervé Claustre

Sensors 2021, 21(18), 6217; https://doi.org/10.3390/s21186217 - 16 Sep 2021

Cited by 4 | Viewed by 2634

Abstract

Measuring the underwater light field is a key mission of the international Biogeochemical-Argo program. Since 2012, 0–250 dbar profiles of downwelling irradiance at 380, 412 and 490 nm besides photosynthetically available radiation (PAR) have been acquired across the globe every 1 to 10 days. The resulting unprecedented amount of radiometric data has been previously quality-controlled for real-time distribution and ocean optics applications, yet some issues affecting the accuracy of measurements at depth have been identified such as changes in sensor dark responsiveness to ambient temperature, with time and according to the material used to build the instrument components. Here, we propose a quality-control procedure to solve these sensor issues to make Argo radiometry data available for delayed-mode distribution, with associated error estimation. The presented protocol requires the acquisition of ancillary radiometric measurements at the 1000 dbar parking depth and night-time profiles. A test on >10,000 profiles from across the world revealed a quality-control success rate >90% for each band. The procedure shows similar performance in re-qualifying low radiometry values across diverse oceanic regions. We finally recommend, for future deployments, acquiring daily 1000 dbar measurements and one night profile per year, preferably during moonless nights and when the temperature range between the surface and 1000 dbar is the largest. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

17 pages, 5040 KiB

Open AccessArticle

A Mosaic Method for Side-Scan Sonar Strip Images Based on Curvelet Transform and Resolution Constraints

by Ning Zhang, Shaohua Jin, Gang Bian, Yang Cui and Liang Chi

Sensors 2021, 21(18), 6044; https://doi.org/10.3390/s21186044 - 9 Sep 2021

Cited by 6 | Viewed by 2245

Abstract

Due to the complex marine environment, side-scan sonar signals are unstable, resulting in random non-rigid distortion in side-scan sonar strip images. To reduce the influence of resolution difference of common areas on strip image mosaicking, we proposed a mosaic method for side-scan sonar strip images based on curvelet transform and resolution constraints. First, image registration was carried out to eliminate dislocation and distortion of the strip images. Then, the resolution vector of the common area in two strip images were calculated, and a resolution model was created. Curvelet transform was then performed for the images, the resolution fusion rules were used for Coarse layer coefficients, and the maximum coefficient integration was applied to the Detail layer and Fine layer to calculate the fusion coefficients. Last, inverse Curvelet transform was carried out on the fusion coefficients to obtain images in the fusion area. The fusion images in multiple areas were then combined in the registered images to obtain the final image. The experiment results showed that the proposed method had better mosaicking performance than some conventional fusion algorithms. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Figure 1

Other

Jump to: Research

8 pages, 2932 KiB

Open AccessTechnical Note

Deriving Large-Scale Coastal Bathymetry from Sentinel-2 Images Using an HIGH-Performance Cluster: A Case Study Covering North Africa’s Coastal Zone

by Mohamed Wassim Baba, Gregoire Thoumyre, Erwin W. J. Bergsma, Christopher J. Daly and Rafael Almar

Sensors 2021, 21(21), 7006; https://doi.org/10.3390/s21217006 - 22 Oct 2021

Cited by 6 | Viewed by 2378

Abstract

Coasts are areas of vitality because they host numerous activities worldwide. Despite their major importance, the knowledge of the main characteristics of the majority of coastal areas (e.g., coastal bathymetry) is still very limited. This is mainly due to the scarcity and lack of accurate measurements or observations, and the sparsity of coastal waters. Moreover, the high cost of performing observations with conventional methods does not allow expansion of the monitoring chain in different coastal areas. In this study, we suggest that the advent of remote sensing data (e.g., Sentinel 2A/B) and high performance computing could open a new perspective to overcome the lack of coastal observations. Indeed, previous research has shown that it is possible to derive large-scale coastal bathymetry from S-2 images. The large S-2 coverage, however, leads to a high computational cost when post-processing the images. Thus, we develop a methodology implemented on a High-Performance cluster (HPC) to derive the bathymetry from S-2 over the globe. In this paper, we describe the conceptualization and implementation of this methodology. Moreover, we will give a general overview of the generated bathymetry map for NA compared with the reference GEBCO global bathymetric product. Finally, we will highlight some hotspots by looking closely to their outputs. Full article

(This article belongs to the Special Issue Advanced Sensing Technology for Ocean Observation)

► Show Figures

Journal Menu

Journal Browser

Advanced Sensing Technology for Ocean Observation

Share This Special Issue

Special Issue Editor

Special Issue Information

Benefits of Publishing in a Special Issue

Published Papers (10 papers)

Research

Other

Further Information

Guidelines

MDPI Initiatives

Follow MDPI