Ship Track Research Articles

TriangularSORT: A Deep Learning Approach for Ship Wake Detection and Tracking

Ship wake detection and tracking are of paramount importance for ensuring maritime safety, conducting effective ocean monitoring, and managing maritime affairs, among other critical applications. This paper introduces a novel approach for ship tracking and wake detection utilizing advanced computational techniques, particularly the TriangularSORT algorithm for monitoring vessels. This method enhances effective ship tracking by closely associating the vertices of the triangular wake with the coordinates of the ship. Furthermore, this paper integrates the triangular IoU and attention mechanism, introducing the Triangular Attention Mechanism. This mechanism guides the model’s focus to key areas of the image by defining triangular points on the feature map, thereby enhancing the model’s ability to recognize and analyze local features in visual tasks. Experimental results demonstrate that the proposed method significantly improves the performance and accuracy of models in object detection and tracking tasks.

Autonomous detection, localization and tracking of ships by underwater acoustic sensing using vector sensor array

Autonomous detection, localization and tracking of ships by underwater acoustic sensing using vector sensor array

Weak liquid water path response in ship tracks

Abstract. The assessment of aerosol–cloud interactions remains a major source of uncertainty in understanding climate change, partly due to the difficulty in making accurate observations of aerosol impacts on clouds. Ships can release large numbers of aerosols that serve as cloud condensation nuclei, which can create artificially brightened clouds known as ship tracks. These aerosol emissions offer a “natural”, or “opportunistic”, experiment to explore aerosol effects on clouds, while also disentangling meteorological influences. Utilizing ship positions and reanalysis wind fields, we predict ship track locations, colocating them with satellite data to depict the temporal evolution of cloud properties after an aerosol perturbation. Repeating our analysis for a null experiment does not necessarily recover zero signal as expected; instead, it reveals subtleties between different null-experiment methodologies. This study uncovers a systematic bias in prior ship track research, due to the assumption that background gradients will, on average, be linear. We correct for this bias, which is linked to the correlation between wind fields and cloud properties, to reveal the true ship track response. We find that, once this bias is corrected for, the liquid water path (LWP) response after an aerosol perturbation is weak on average. This has important implications for estimates of radiative forcings due to LWP adjustments, as previous responses in unstable cases were overestimated. A noticeable LWP response is only recovered in specific cases, such as marine stratocumulus clouds, where a positive LWP response is found in precipitating or clean clouds. This work highlights subtleties in the analysis of isolated opportunistic experiments, reconciling differences in the LWP response to aerosols reported in previous studies.

Quality Assurance of a "Booster Program" for Gender Equity in the Academia: From Vision to Practice

Even as the 21st century unfolds, it is well recognized that women in the academic world struggle more to secure research funding and are still largely underrepresented at the level of full professorship, the highest post possible within universities and colleges. To rectify this gender-based inequality, a mid-sized academic college initiated an original program named "Booster" aiming for it to provide the optimal framework for creating a nurturing space for the promotion of prominent female faculty members, mainly to the high rank of "professor." The aim of this research was to find whether the booster plan has fulfilled its rectifying objectives according to the quality assurance model of the Plan - Do - Check - Action (PDCA) cycle. As a research method, an evaluation study was selected to examine the operation of the program, mainly from the perspective of the participants. The evaluation of the program was combined with both quantitative and qualitative assessments. The main finding indicated that the participants in the program had reported a high-level satisfaction. It was also found that the vast majority of the participants mentioned their understanding of promotion procedures as the most important tool they acquired in the program. The main importance of this study is in adding knowledge about ways to identify the "blind spots" and weaknesses of academia that shape the unjust "leaky pipeline" structure in gender contexts, from the stage in which women enter academia, through their tenure- ship track as faculty, to the processes of promotion up the ranks.

An inland waterway traffic complexity evaluation method using radar sequential images

An inland waterway traffic complexity evaluation method using radar sequential images

Strategi Penanganan Illegal Fishing oleh Kapolairud Baharkam di Laut Natuna Utara untuk Memperkuat Keamanan Nasional

Illegal fishing in the North Natuna Sea is a serious threat to Indonesia, both in terms of economy and state sovereignty. Disputed waters, especially in Indonesia's Exclusive Economic Zone (EEZ), are often targeted by foreign vessels with various modus operandi, such as identity forgery and detection evasion. The purpose of this study is to analyze the strategy for handling illegal fishing implemented by the Baharkam Police Chief in the North Natuna Sea to maintain national security. The research method used is qualitative descriptive with SWOT analysis. SWOT analysis is applied to evaluate the strengths, weaknesses, opportunities, and threats faced in handling illegal fishing in the region. The results of the study show that an effective strategy requires the integration of advanced technologies such as radar, thermal sensors, and ship tracking systems (VTMS), as well as strong national policy support. The Baharkam Police Chief also benefits from new technologies such as Sat-AIS and maritime drones, which play an important role in maritime surveillance. Comprehensive personnel training and the development of ships and patrol aircraft are important elements in strengthening the operational capabilities of the Kapolairud in dealing with illegal fishing and defending the sovereignty of Indonesian waters.

Correction to: Human Tales on the Pathless Sea? Imperial Subjectivities and Exploration Ship Tracks in European Maritime Mapping, c.1500–c.1800

Correction to: Human Tales on the Pathless Sea? Imperial Subjectivities and Exploration Ship Tracks in European Maritime Mapping, c.1500–c.1800

Sea-air CO2 exchanges, pCO2 drivers and phytoplankton communities in the southwestern South Atlantic Ocean during spring

Sea-air CO2 exchanges, pCO2 drivers and phytoplankton communities in the southwestern South Atlantic Ocean during spring

Spatiotemporal upscaling of sparse air-sea pCO2 data via physics-informed transfer learning

Global measurements of ocean pCO2 are critical to monitor and understand changes in the global carbon cycle. However, pCO2 observations remain sparse as they are mostly collected on opportunistic ship tracks. Several approaches, especially based on direct learning, have been used to upscale and extrapolate sparse point data to dense estimates using globally available input features. However, these estimates tend to exhibit spatially heterogeneous performance. As a result, we propose a physics-informed transfer learning workflow to generate dense pCO2 estimates that are grounded in real-world measurements and remain physically consistent. The models are initially trained on dense input predictors against pCO2 estimates from Earth system model simulation, and then fine-tuned to sparse SOCAT observational data. Compared to the benchmark direct learning approach, our transfer learning framework shows major improvements of up to 56-92%. Furthermore, we demonstrate that using models that explicitly account for spatiotemporal structures in the data yield better validation performances by 50-68%. Our strategy thus presents a new monthly global pCO2 estimate that spans for 35 years between 1982-2017.

Deep sediment heterogeneity inferred using very low-frequency features from merchant shipsa).

The very low-frequency noise from merchant ships provides a good broadband sound source to study the deep layers of the seabed. The nested striations that characterize ship time-frequency spectrograms contain unique acoustic features corresponding to where the waveguide invariant β becomes infinite. In this dataset, these features occur at frequencies between 20 and 80 Hz, where pairs of modal group velocities become equal. The goal of this study is to identify these β = ∞ frequencies in ship noise spectrograms and use them to perform statistical inference for the deep layer sound speeds and thicknesses in the New England Mudpatch for a larger number of ships and acoustic arrays over a larger geographical region than previously studied. Marginal probability distributions of the data indicate that using singular points for a feature-based inversion yields an estimate of the sound speed and a limiting value for the thickness of the first deep layer. Heterogeneity is examined by correlating spatial variability of the deep layer sound speeds with ship tracks.

Long-term tracking for high-frequency surface wave radar based on heading constraint filtering combined ELM

Abstract Aiming at the problem of low measurement resolution and poor tracking accuracy in High-frequency surface wave radar (HFSWR) tracking field, a tracking method that combines the heading constraint filter and Extreme Learning Machine (ELM) is proposed. Compared with the existing research, the innovation of this study lies in proposing a two-stage tracking method based on the short-term stable state of the target, and similarity of long-term trajectory. Firstly, the heading constraint information is introduced into the estimator and improve the estimation accuracy. In multi-target tracking scenarios, many tracklets can be obtained. Then, the ELM learns robust features of tracklets to achieve the trajectory segment classification from the same target. This method can be widely applied to long-term tracking of cargo or passenger ships with fixed destinations, significantly improving tracking performance by utilizing implicit domain knowledge without additional information. The actual data of this paper comes from HFSWR on Bohai Bay. Both the simulation and actual measurement experiments show that the proposed cascaded tracking method achieves long-term continuous tracking, and generates more complete trajectories. Moreover, the proposed Extended Kalman filter based on pseudo-measurement and intercept parameters (IPM-EKF) exhibits better tracking stability and accuracy in limited scan steps. This study provides new ideas and methods for improving the tracking performance of special targets in the HFSWR field by utilizing motion features.

Examining fishing activities based on in-situ tracking and oceanographic characteristics in Aru Sea and surroundings

Examining fishing activities based on in-situ tracking and oceanographic characteristics in Aru Sea and surroundings

Analysis of the impact of Arctic environment conditions on the psychophysical status of navigators and safety of ice navigation

Abstract The Arctic is a specific geographical region, whose environment effects any person's staying and working there, so it demands researching and accounting in the practice of ice navigation. The most difficult period of navigation is the winter-spring time, when Arctic Seas are covered by an ice cover. Ice navigation is always associated with a large number of difficulties for the crewmen, not only because of the geographical location of the water area, but also the climatic and environment conditions that impact on the mental and physical state of crewmen. These conditions, namely, the length of the polar night and day, the extreme frosts, maximum number of foggy days, and the duration of the ice period on all the tracks of the cargo ships along the North Sea Route were selected and analysed as the dominant factors that impact on the ship's crewmen. The analysis was performed on the base of the ‘Matrix of Arctic Impacts’ arraying that summarizes data about the level of the selected factors displayed in the local water areas along the North Sea Route and provided the selection of the local water areas with the most impacts of Arctic environment factors on the psychophysical status of the crewmen. In these water areas, accidents caused by the ‘human factor’ are most likely to occur. Therefore, special researches of the Arctic environment's impact on navigators is required in order to improve the safety of ice navigation.

Optimizing observational arrays for biogeochemistry in the tropical Pacific by estimating correlation lengths

AbstractGlobal climate change has impacted ocean biogeochemistry and physical dynamics, causing increases in acidity and temperature, among other phenomena. These changes can lead to deleterious effects on marine ecosystems and communities that rely on these ecosystems for their livelihoods. To better quantify these changes, an array of floats fitted with biogeochemical sensors (BGC‐Argo) is being deployed throughout the ocean. This paper presents an algorithm for deriving a deployment strategy that maximizes the information captured by each float. The process involves using a model solution as a proxy for the true ocean state and carrying out an iterative process to identify optimal float deployment locations for constraining the model variance. As an example, we use the algorithm to optimize the array for observing ocean surface dissolved carbon dioxide concentrations (pCO2) in a region of strong air–sea gas exchange currently being targeted for BGC‐Argo float deployment. We conclude that 54% of the pCO2 variability in the analysis region could be sampled by an array of 50 Argo floats deployed in specified locations. This implies a relatively coarse average spacing, though we find the optimal spacing is nonuniform, with a denser sampling being required in the eastern equatorial Pacific. We also show that this method could be applied to determine the optimal float deployment along ship tracks, matching the logistics of real float deployment. We envision this software package to be a helpful resource in ocean observational design anywhere in the global oceans.

Lightweight multiobject ship tracking algorithm based on trajectory association and improved YOLOv7tiny

Lightweight multiobject ship tracking algorithm based on trajectory association and improved YOLOv7tiny

Has Reducing Ship Emissions Brought Forward Global Warming?

AbstractShips brighten low marine clouds from emissions of sulfur and aerosols, resulting in visible “ship tracks”. In 2020, new shipping regulations mandated an ∼80% reduction in the allowed fuel sulfur content. Recent observations indicate that visible ship tracks have decreased. Model simulations indicate that since 2020 shipping regulations have induced a net radiative forcing of +0.12 Wm−2. Analysis of recent temperature anomalies indicates Northern Hemisphere surface temperature anomalies in 2022–2023 are correlated with observed cloud radiative forcing and the cloud radiative forcing is spatially correlated with the simulated radiative forcing from the 2020 shipping emission changes. Shipping emissions changes could be accelerating global warming. To better constrain these estimates, better access to ship position data and understanding of ship aerosol emissions are needed. Understanding the risks and benefits of emissions reductions and the difficultly in robust attribution highlights the large uncertainty in attributing proposed deliberate climate intervention.

Deep Learning-Based Detection and Robust Tracking of an Unmanned Surface Ship Using a Monocular Camera

Deep Learning-Based Detection and Robust Tracking of an Unmanned Surface Ship Using a Monocular Camera

Arctic accessibility: recent trend in observed ship tracks and validation of arctic transport accessibility model

ABSTRACT The Arctic region is undergoing significant changes in maritime accessibility. This study investigates observed ship trajectories from 2013 to 2020 to demonstrate the recent trends of Arctic traffic. A notable surge in maritime activities has been observed, particularly during summer months, driven by economic interests and the increasing popularity of existing routes. Unique patterns in the northern Barents Sea have been observed where ships favour different routes based on seasonal ice conditions. Another contribution from this work is the validation of the Arctic Traffic Accessibility Model (ATAM) using the observed ship traffic data. Results show that the ATAM model underestimates the accessibility and vessel travel speed. This is largely due to outdated model parameters. The predefined ice multipliers and calculation of ice numerals used in the ATAM may not accurately reflect real-world conditions.

Human Tales on the Pathless Sea? Imperial Subjectivities and Exploration Ship Tracks in European Maritime Mapping, c.1500–c.1800

Abstract During the Renaissance, Europeans began to mark sea journeys on maps and charts as lines or dotted lines—‘ship tracks’. This new graphical depiction of voyages, which flanked and often replaced verbal itinerary descriptions, ultimately lies behind present-day route-marking devices, but it has not been much investigated by historians. Tracing its development between the sixteenth and the early nineteenth centuries, through cartographic sources, hydrographical manuals and voyage accounts, this article argues that ship tracks constituted a fundamental turning point in European understandings of human movement and influence in the world. In particular, the tracks of late eighteenth-century imperial explorers, built through novel accuracy claims, established a unique cognitive and ontological link between representation and reality and between human agency and the natural world, and explicitly embedded the perspectival subjectivity of storytelling into the alleged objectivity of ‘scientific’ geometrisations of the globe. As such, tracks are useful tools with which to understand and deconstruct the roots of ‘modernity/coloniality’. They also reveal the extent to which maritime history holds important keys to the past: as a representational and directional device, the modern journey track owes much of its ancestry to confrontation with the liquid and supposedly ‘pathless’ sea.

Climate and air quality impact of using ammonia as an alternative shipping fuel

As carbon-free fuel, ammonia has been proposed as an alternative fuel to facilitate maritime decarbonization. Deployment of ammonia-powered ships is proposed as soon as 2024. However, NO x , NH3 and N2O from ammonia combustion could impact air quality and climate. In this study, we assess whether and under what conditions switching to ammonia fuel might affect climate and air quality. We use a bottom–up approach combining ammonia engine experiment results and ship track data to estimate global tailpipe NO x , NH3 and N2O emissions from ammonia-powered ships with two possible engine technologies (NH3–H2 (high NO x , low NH3 emissions) vs pure NH3 (low NO x , very high NH3 emissions) combustion) under three emission regulation scenarios (with corresponding assumptions in emission control technologies), and simulate their air quality impacts using GEOS–Chem high performance global chemical transport model. We find that the tailpipe N2O emissions from ammonia-powered ships have climate impacts equivalent to 5.8% of current shipping CO2 emissions. Globally, switching to NH3–H2 engines avoids 16 900 mortalities from PM2.5 and 16 200 mortalities from O3 annually, while the unburnt NH3 emissions (82.0 Tg NH3 yr−1) from pure NH3 engines could lead to 668 100 additional mortalities from PM2.5 annually under current legislation. Requiring NH3 scrubbing within current emission control areas leads to smaller improvements in PM2.5-related mortalities (22 100 avoided mortalities for NH3–H2 and 623 900 additional mortalities for pure NH3 annually), while extending both Tier III NO x standard and NH3 scrubbing requirements globally leads to larger improvement in PM2.5-related mortalities associated with a switch to ammonia-powered ships (66 500 avoided mortalities for NH3–H2 and 1200 additional mortalities for pure NH3 annually). Our findings suggest that while switching to ammonia fuel would reduce tailpipe greenhouse gas emissions from shipping, stringent ammonia emission control is required to mitigate the potential adverse effects on air quality.