Calm Sea Research Articles

Ultrasonic measurement of oil slick thickness using a remotely operated vehicle (ROV) as a platform in various sea wave states

To overcome the difficulty of estimating the oil slick thickness using remote sensing techniques, the feasibility of applying the proposed ultrasonic method for measuring the thickness of the oil slick in open water was experimentally investigated by conducting tests in various sea wave states. The second cross-correlation method was implemented to calculate the time of flight (TOF). The influences of sea waves on measurement accuracy were deeply evaluated by calculating the difference of the average thickness in the sea wave state compared with the average thickness in the calm sea state (no waves). The results showed a high measurement accuracy with a maximum difference ∼17.3%, and most of the tests (10 in 15) had a difference within ±10%. The measurement accuracy was further improved by correcting singular thicknesses caused by the ROV's pitch and roll, and surface waves. The study will advance the development and transition of this method to be implemented in open water.

A theoretical model of excess attenuation of acoustic signals propagating under cracked sea-ice landscapes.

The Arctic sheet is transitioning from a continuous cover of thick multi-year ice to a fragmented landscape of thin young ice. If the type of acoustic transmission allows repetitive interaction of rays with the sea surface, in the fragmented scenario acoustic rays will undergo a random sequence of reflections from water or sea-ice interfaces. Calm sea conditions in the water channels between the ice floes (leads) and the smooth, flat surface of the young ice bottom reduce scattering due to interface roughness, resulting only in scattering due to inhomogeneity in surface reflectivity. Using an idealized framework, this study investigates the extent to which the mid- to high-frequency underwater acoustic propagation is altered due to repetitive interactions of acoustic signals with a sea surface consisting of a random distribution of ice sheets and leads. An expression for the coherent field (the acoustic field averaged over an ensemble of realizations of sea-ice distributions) was derived from theory. Any deviation from a homogeneous surface condition (either by randomly adding ice slabs in a free ice surface or by including leads in a fully ice-covered sea surface) leads to an excess attenuation of the coherent field. Results are validated by numerical simulations.

X-Band Radar Detection of Small Garbage Islands in Different Sea State Conditions

This paper presents an assessment of X-band radar’s detection capability to monitor Small Garbage Islands (SGIs), i.e., floating aggregations of marine litter consisting chiefly of plastic, under changing sea states. For this purpose, two radar measurement campaigns were carried out with controlled releases at sea of SGI modules assembled in the laboratory. One campaign was carried out with a calm sea and almost no wind in order to determine the X-band radar system’s detection capabilities in an ideal scenario, while the other campaign took place with rough seas and wind. An analysis of the data acquired during the campaigns confirmed that X-band radar can detect small aggregations of litter floating on the sea surface. To demonstrate the radar’s ability to detect SGIs, a statistical analysis was carried out to calculate the probability of false alarm and the probability of detection for two releases at two different distances from the radar. For greater readability of this work, all of the results obtained are presented both in terms of radar intensity and in terms of the radar cross-section relating to both the targets and the clutter. Another interesting study that is presented in this article concerns the measurement of the speed of movement (drift) of the SGIs compared with the measurement of the speed of the surface currents provided at the same time by the radar. The study also identified the radar detection limits depending on the sea state and the target distance from the antenna.

Turbulent Flows Are Not Uniformly Multifractal.

Understanding turbulence rests delicately on the conflict between Kolmogorov's 1941 theory of nonintermittent, space-filling energy dissipation characterized by a unique scaling exponent and the overwhelming evidence to the contrary of intermittency, multiscaling, and multifractality. Strangely, multifractality is not typically envisioned as a local flow property, variations in which might be clues exposing inroads into the fundamental unsolved issues of anomalous dissipation and finite time blowup. We present a simple construction of local multifractality and find that much of the dissipation field remains surprisingly monofractal àla Kolmogorov. Multifractality appears as small islands in this calm sea, its strength growing logarithmically with the local fluctuations in energy dissipation-a seemingly universal feature. These results suggest new ways to understand how singularities could arise and provide a fresh perspective on anomalous dissipation and intermittency. The simplicity and adaptability of our approach also holds great promise in applications ranging from climate sciences to medical data analysis.

Analysis of turning ability of large tankers with and without bulbous bow in calm sea and waves

The present study introduces an experimental and numerical investigation of the turning ability of two ships with and without a bulbous bow: original and modified KVLCC2 hulls Experiments are performed via free-running model tests in a square basin, and a system-based simulation are performed. The maneuvering coefficients for the system-based solver are obtained via numerical planar motion mechanism (PMM) tests based on CFD computations, and other variables are obtained from reference ships. The effects of ship speed, wave direction, and wavelength are investigated. Results of a calm-water turning test obtained experimentally and numerically agree well. When the ship turns in the presence of incident waves, the overall behavior and evaluation parameters predicted in the simulation are similar to those obtained from experiments. However, the evaluation parameters show scattered values under severe turning-failure conditions. The most significant wave effects are observed in short waves. Additionally, the turning ability is compared between two ships, and slightly different maneuvering capabilities are observed. The time series for two hulls are further compared to investigate the reason for the difference showing the difference in the force and drift angle time series.

Introducing the Azimuth Cutoff as an Independent Measure for Characterizing Sea-State Dynamics in SAR Altimetry

This study presents the first azimuth cutoff analysis in Synthetic Aperture Radar (SAR) altimetry, aiming to assess its applicability in characterizing sea-state dynamics. In SAR imaging, the azimuth cutoff serves as a proxy for the shortest waves, in terms of wavelength, that can be detected by the satellite under certain wind and wave conditions. The magnitude of this parameter is closely related to the wave orbital velocity variance, a key parameter for characterizing wind-wave systems. We exploit wave modulations exhibited in the tail of fully-focused SAR waveforms and extract the azimuth cutoff from the radar signal through the analysis of its along-track autocorrelation function. We showcase the capability of Sentinel-6A in deriving these two parameters based on analyses in the spatial and wavenumber domains, accompanied by a discussion of the limitations. We use Level-1A high-resolution Sentinel-6A data from one repeat cycle (10 days) globally to verify our findings against wave modeled data. In the spatial domain analysis, the estimation of azimuth cutoff involves fitting a Gaussian function to the along-track autocorrelation function. Results reveal pronounced dependencies on wind speed and significant wave height, factors primarily determining the magnitude of the velocity variance. In extreme sea states, the parameters are underestimated by the altimeter, while in relatively calm sea states and in the presence of swells, a substantial overestimation trend is observed. We introduce an alternative approach to extract the azimuth cutoff by identifying the fall-off wavenumber in the wavenumber domain. Results indicate effective mitigation of swell-induced errors, with some additional sensitivity to extreme sea states compared to the spatial domain approach.

Clustering dimensionless learning for multiple-physical-regime systems

The conventional physical analysis has relied on the researchers’ intelligence and physical insights to establish mathematical models and analyze the dependence of physical systems on dominant parameters in different physical regimes. In this work, a novel data-driven method is proposed to identify different physical regimes without a prior knowledge of governing equations and discover the dominant dimensionless parameters. The proposed method consists of two parts: the first is a data division via cluster analysis, which is utilized to identify different physical regimes via grouping data points into clusters with the weights taken from the key features in active subspace method; the second is a data-driven analysis of dominant dimensionless parameters via the active subspace, which is utilized to discover dominant dimensionless parameters by use of clustering and its resultant information (e.g. eigenpairs of clusters). We use three example problems to demonstrate this method: pipe flows, the spread of oil slicks on a calm sea, and the eddy viscosity in turbulent channel flows. The results obtained show that the present method can identify distinct physical regimes, and discover dominant dimensionless parameters, while the data-driven dimensional analysis without clustering cannot be directly used to the physical systems of multiple physical regimes.

The Concepts of Planning in Architecture and Environtment to Mitigate Tsunami Disaster Case Study: Semawang Beach, Denpasar, Bali

Bali won the title of “World's Favorite Tourist Destination Destination” at the 2020 PVK Award. This title is inseparable from the many natural and cultural tourist objects that attract local and foreign tourists to visit Bali, one of which is Semawang Beach, Denpasar. The wide, white and shallow coastal area, calm sea conditions, a favorite place to enjoy the sunrise, the many gazebos and tourism accommodations, the location near Ngurah Rai International Airport is the main attraction for tourists. However, according to information from the Head of the National BMKG Prof. Dwikorita Karnawati said that the southern region of East Java and Bali, including Semawang Beach, has the threat of an earthquake accompanied by a tsunami in the future which we cannot predict exactly when it will occur. Based on this, it can be concluded that what is the solution, especially from the engineering side, especially architecture, which creates beaches that are safe for tourists to visit in the form of permeable architectural and environmental models that support tsunami disaster mitigation. Specifically for the first year, the existing model will be evaluated first so that it is hoped that in the second year a permeable design model will be produced. This study uses a descriptive qualitative approach using observation data, surveys, and documents. The research instruments were coastal base maps, total station tools, laser meters, stationery, autocad and 3d sketchup software, cameras and computers. The research which is planned for 9 months in the first year is expected to produce findings of evaluation of existing permeable architectural and environmental models in supporting tsunami disaster mitigation in the Semawang Beach area, Denpasar in terms of evacuation rescue routes, protective areas, safe zones, open spaces, facilities general disaster response, and determinants of disaster response in spatial planning and buildings.

Experimental study on the stable and dynamic characteristics during silicone oil spreading process on saline water sublayer with different salinities under various temperature conditions

This study investigated the influence of salinity on the spreading behavior of oil at varying temperatures on a calm sea surface through a series of experiments involving the spreading of silicone oil on saline water sublayers with salinities of 0, 5, 10, and 20 ppt (parts per thousand, equivalent to 1‰) across a range of temperatures from 5 to 35 °C. Real-time observations were made of the oil's morphology from both top and side perspectives. The top-view area of the oil slick was not only recorded, but also the side-view morphology of the oil slick was tracked and photographed during the whole process, and the dynamic process of the angle and thickness was measured. The results indicate that higher temperatures and salinity levels increase spreading area. The stable angle was determined by considering three-phase surface tension and Neumann’s rule. The stabilized thickness based on the angle is derived by combining capillary pressure analysis and the Young-Laplace equation. A dynamic thickness model was developed based on force analysis, primarily relying on differential pressure force and surface tension. This study offers valuable theoretical insights to aid in predicting the oil spread thickness of oil spills in various sea regions.

Numerical study on the lifting operation of a gravity-type fish cage

The dynamic behaviours of the lifting operation of a gravity-type fish cage under calm sea conditions are investigated in this study using an extended position-based dynamics (XPBD) method to obtain the structural deformations of the aquaculture nets. The original XPBD is improved to accurately predict the tensions of the aquaculture nets by applying correction forces. The present XPBD is validated by comparing the experimental results of a flexible horizontal net. The time-step sensitivity is verified for the case of the lifting operation of the fish cage. Results show that the lifting force increases rapidly resulting from the weight of the sinkers at the bottom of the side net. The maximum tension of the net is located at the net ropes connected to the centre point of the bottom net. The structure of the bottom net should be enhanced for safety lifting operations.

ANALISIS KEPUASAN PENGUNJUNG DAN POTENSI PENGEMBANGAN PADA OBJEK WISATA PANTAI MUTUN DI KABUPATEN PESAWARAN

This study aims to analyze the level of visitors’ satisfaction at Mutun Beach, the tourist attributes that need to be improved and maintained by Mutun Beach, and to find out the driving and inhibiting factors development of Mutun Beach. The method used in this research was a survey method. The samples in this study were 4 Mutun employees and 77 visitors, which were taken using purposive sampling and accidental sampling methods. Data collection was carried out in January - February 2023. The data analysis methods used were Customer Satisfaction Index (CSI), Importance Performance Analysis (IPA), and descriptive analysis. The results of this study indicated that the level of visitor satisfaction is in the "Satisfied" category with a CSI value of 74.77%. Based on the IPA method, tourism attributes that need to be improved are the condition of game facilities such as banana boats, rubber boats and water booms, the safety of water boom, and the condition of toilet and prayer room facilities. Tourism attributes that need to be maintained are the attractiveness of the beach, cleanliness, comfortable atmosphere, calm sea water, various and condition of infrastructure and game facilities, and good service. Factors that are driving the development of Mutun Beach are high tourist attractiveness, easy accessibility, complete facilities, good service and management, and government’s role. The inhibiting factors are limited promotion, competitors or other beaches around Mutun, and limited funds and human resources.Key words: CSI, development potential, IPA, visitor satisfaction

Numerical study on static drift tests for ship maneuvering in regular waves

This study is driven by the coupled seakeeping–maneuvering analysis, which predicts ship maneuverability in waves by combining seakeeping analysis with a mathematical maneuvering model. The traditional maneuvering model and its corresponding coefficients are developed based on calm sea conditions, where wave effects are typically disregarded as a temporary compromise. It is an inevitable need to revisit the mathematical maneuvering model or coefficients by considering wave effects. To this end, in this study, a series of static drift tests are employed in waves to investigate the influence of wave effects on the sway damping coefficients of ship maneuvering motion. These tests are conducted using a numerical tank, which overcomes spatial constraints and maintains a reliable wave field for ship–wave interactions. Three wave parameters, namely wavelength, wave steepness, and wave direction, are considered to assess their impacts on the wave-induced motions and forces. Furthermore, the wave effects on the maneuvering coefficients are summarized and discussed using direct observations of ship-turning motions in waves. Additionally, the benefits of computational fluid dynamics analysis are utilized to showcase the strong nonlinear phenomena of ship–wave interactions.

Studies on the complex Warnowiaceae (Dinophyceae) I. Lohmann’s Pouchetia parva refound and renamed Nematodinium parvum comb. nov. (= Warnowia parva)

ABSTRACT The dinoflagellate family Warnowiaceae has often been considered to include some of the most complex cells among the protists. The number of described species is around 40, but both the species and generic concepts are in need of revision. Warnowiaceans are often fragile and readily change morphology under the light microscope, and they are usually regarded to be rare. They are particularly famous for the eye-like structures, termed ocelloids. Studies on warnowiaceans are hampered by lack of cultures, and our studies are therefore based on cells obtained directly from field samples. We provide a description of Nematodinium parvum comb. nov. (syn. Pouchetia parva, Warnowia parva), based on light, scanning and transmission electron microscopy, combined with phylogenetic analyses of ribosomal genes. It was described in 1908 by Lohmann from Kieler Bay, but is often common in Danish waters, allowing observations on distribution and behaviour. Crucial conditions for finding high cell abundances were periods of warm temperatures and a calm sea. Cells were yellowish, photosynthetic, and contained a net-like chloroplast, in addition to an ocelloid, trichocysts and harpoon-like nematocysts. They divided asexually but planozygotes were also seen. Following the demonstration of nematocysts, the species, which has been known as Warnowia parva since 1928, is transferred to Nematodinium. The finding of a peduncle indicates mixotrophy but all feeding experiments failed to identify a suitable prey. The phylogenetic analyses based on single-cell PCR and sequence determinations of small and large subunit rDNA confirmed that the systematics of Nematodinium and Warnowia is in a state of flux.

Biofilm prevention in the generator of a direct drive wave energy converter

Power take off in a wave energy converter has a number of unique requirements. It must convert low speed oscillating motion into electricity in a reliable, low maintenance manner. A direct drive system, where the electrical machine is optimised to operate at low speed, has the potential to offer a mechanically robust and simple solution. Similar to a hydraulic power take off, the only regular maintenance would be to inspect and replace the seal between moving parts. One strategy for removing regular maintenance is to have an unsealed system, i.e. one where sea water is allowed throughout the electrical machine. A fully flooded electrical machine has benefits in terms of cooling, but poses challenges relating to reliability, corrosion, biofouling and lubrication.
 Biofilm refers to a thin layer of fouling organisms which can interfere with the operation of components. Recent work has found that submerged surfaces can be kept free of biofouling using projected ultraviolet (UV) light from LEDs. This paper discusses the testing procedure and impact of the UVC irradiation on biofilm prevention within the active part of an electric generator in a systematic manner, with a view to accelerate its translation to full-scale applications.
 A prototype generator is being developed which will be installed in the North Sea, consisting of a submerged linear tubular electrical machine. A magnetic tubular translator will oscillate within a cylinder that houses stator coils. Lubrication will be by way of solid polymer bearings. In order that the active part of the electrical machine can oscillate smoothly, it is imperative that biofilm is prevented from colonising on the bearing surface, which also makes up the magnetic gap of the electrical machine.
 The system will have a slow reciprocating oscillation, with a peak speed of perhaps 2m/s. For most wave energy converters there will be brief static periods twice in every wave, and in calm seas these could be prolonged to several hours or even days. In low energy sea states oscillation amplitude could be less than the fully rated amplitude, meaning different parts of the bearing surface could be exposed for different amounts of time.
 Early-stage work is underway to investigate the use of UV irradiation in the active part of the electrical machine and bearing surface as biofilm prevention. Flat panels (600mm x 220mm) are used to simulate the original surfaces between moving parts. To achieve biofilm growth, an artificial slime farm was deployed which allows test panels to be subjected to a continuous dynamic flow. The light source of UV irradiation was provided by Light Emitting Diodes (LEDs) with 278nm wavelength. The effectiveness of the biofilm prevention by UVC were evaluated by Image Analysis
 The results indicate that UVC can significantly control biofilm presence on the panels. It also has demonstrated that intermittent UV can achieve successful biofilm prevention on submerged surfaces. However, observations indicate the actual UVC light intensity may perform below the manufacturer’s specifications, and this could lead to a detrimental effect on its biofilm control performance.

STRATEGI PENGEMBANGAN PARIWISATA BAHARI (STUDI KASUS: PANTAI EKAS KABUPATEN LOMBOK TIMUR)


 
 
 
 This study discusses the Marine Tourism Development Strategy of Ekas Beach, East Lombok Regency. The results of the study are described in several answers to the formulation of the problem, namely to determine the potential for marine tourism attraction of Ekas Beach, then create a SWOT analysis (Strengths, Weaknesses, Opportunities, Threats), in order to find out how the marine tourism development strategy will be carried out at Ekas Beach until in making work programs that can realize the strategy. By using the method of interviews, observations, documentation studies and literature studies and approaches using qualitative descriptive. The results of this study indicate that Ekas Beach has the potential to attract competitive marine tourism from the shoreline, towering hills around the shoreline, underwater beauty, calm sea water and lobster cultivation. Ekas Beach has now begun to be managed by the Village Government and Local Communities by taking advantage of its attractiveness. Furthermore, the analysis contained in the internal factors (strengths-weaknesses) and external (opportunities-threats) from the identification of attractions and developments that have been carried out is carried out. There are four strategies that were born, namely, Alternative Strategies for Development of Marine Tourism Products, Alternative Strategies for Development of Tourism Institutions and Human Resources, Alternative Strategies for Development of Local Community-Based Tourism. Alternative Strategies for Development of Tourism Human Resources Support and Interest. Then followed up in work programs.
 
 
 

PENGEMBANGAN WISATA PANTAI EKAS BUANA DESA EKAS KECAMATAN JERUWARU KABUPATEN LOMBOK TIMUR

This research discusses the Tourism Development Strategy of Ekas Buana Beach, Jeruwaru District, East Lombok Regency. This research was conducted to answer the formulation of the problem, namely to find out the tourist attraction of Ekas Buana Beach and find out how the strategy of developing Ekas Buana Beach tourism. The writing of this research is presented descriptively to obtain an overview of the attractiveness and tourism development strategy of Ekas Beach. The methods used in data collection are observation, interviews, documentation and literature studies. The results of this study show that Ekas Beach has an extraordinary beach tourist attraction from the side of the beach that stretches out with the exoticness of the sand which is still very beautiful, the hills that rise around the shoreline, the beauty of the underwater, and clear and calm sea water. Ekas Beach has now begun to be managed by the Village Government and Local Communities by utilizing its strengths. The conclusion that can be drawn regarding the development of Ekas Buana Beach tourism is that there are still weaknesses in the development of beach tourism so that a strategy is needed in planning programs to maximize the development of Ekas Beach in increasing tourist visits to Ekas Beach, this will have a good economic impact on the Village Government and the Community.

Modelling and evaluation of beach morphodynamic behavior: A case study of Dongsha Beach in eastern China

Beaches provide natural protection for coast and ecosystems. Storm surges and waves make significant impacts on the topographic changes of beaches, subsequently causing crises of coastal erosion and management. Beach protection and nourishment projects is growing considerably along the world. Five profiles of Dongsha Beach located in the southeast of Zhujiajian Island, eastern China, were measured and used to analyze the cross-shore profile changes, longshore sediment transport, beach rotation and equilibrium shoreline and profile. Delft3D Flow/Wave and XBeach models were established and calibrated to investigate the morphological responses of Dongsha Beach. It was found that: (1) the longshore sediment transport dominated the changes of erosion and accretion sediment volume compared to the cross-shore sediment transport; (2) the shoreline of Dongsha Beach was not in equilibrium condition compared to the profile equilibrium conditions; (3) the longshore sediment transportation was the main reason of the erosion because the shoreline changes caused by longshore sediment transport during the storm condition could not be restored during calm sea periods; (4) the correlation between wave induced currents and Hs2·T was good and the dominating wave direction was 90°. Finally, sediment nourishment projects named N1∼N3 were assumed and simulated to identify the optimum for the dynamic balance of Dongsha beach. Sediment sources with D50 of 0.5 mm should be chosen in sediment nourishment projects, and the nourished area should be selected in N1 or N3 of the beach. The numerical model established in this study could be a useful tool to predict the future erosion and accretion of beaches. This study can provide a useful understanding and reference especially for the embayed beach nourishment, making the beach management decisions more scientific and reasonable.

Armored steel wire stress monitoring strategy of a flexible hose in LNG tandem offloading operation

Cryogenic flexible hose is the key equipment for tandem offloading operation of Floating Liquefied Natural Gas (FLNG). The harsh marine environment leads hulls motion responses and complex hose motion characteristics during the tandem offloading, thus causing various failure behaviors of the entire hose. In this paper, a combined global-local monitoring strategy for armored steel wire stress distributions in cryogenic flexible hose is proposed. High-precision flexible hose governing equations are established by using the function to fit the relationship between the vertical force and the hose length. A reasonable monitoring strategy is given based on the pipeline configuration variations and sensor accuracy. Real-time monitoring of the flexible hose from the global (hose) to the local (armored steel wire) during the tandem offloading is carried out by installing sensors in specified locations on hulls and hose segments. The tandem offloading operation under different (static, calm and harsh) sea states is modelled by Orcaflex software. An armored steel wire model is developed using ABAQUS software. Comparisons of the pipeline configurations, curvatures, axial forces and maximum wire stresses are made with the simulation results to verify the feasibility of the monitoring strategy. The results show that the proposed monitoring strategy in this paper can accurately and effectively obtain the hose motion characteristics and maximum stress states of armored steel wires under different sea states, and can evaluate the hose structural safety in real time during the tandem offloading operation.

We Have to Change to Stay the Same - The Maritime Museum of the Atlantic (Nova Scotia, Canada)

In many ways, it seems that 2022 is a year for renewal. A re-start from a period of closures and other impacts of a devastating pandemic, and from a period of heightened global awareness on social injustice and inequality, racism, increasing threats of war, climate change, species at risk, and ocean conservation. The Maritime Museum of the Atlantic (MMA) hosted the 50th Anniversary International Congress of Maritime Museums (ICMM) in this renewal year offering a robust programme that was heavily influenced by these shared concerns. The combination of embarking on a new half-century, and an unprecedented awareness of significant global issues, provided the obvious opportunity to explore and re-imagine our roles as meaning-making institutions, as impactful maritime museums. Many museums, the MMA included, had already been taking an inward look, trying to understand the impacts of decades of institutional bias and the reality of being part of the climate crisis. So much had changed during the past few years. It had been a long time since we could gather in-person and experience the kind of powerful networking that can only happen face-to-face. I think we had a tremendous appetite to share and discuss our recent experiences and ambitions. The moment was right for a Congress focused on new beginnings and growth. As the saying goes, “Calm seas do not make a good captain,” and we had all been through some pretty rough seas.

A Turbulence Survey in the Gulf of Naples, Mediterranean Sea, during the Seasonal Destratification

The seasonality of the vertical mixing at coastal sites is not well characterized yet. Here, a time series of the dissipation rate of turbulent kinetic energy (ε) was obtained from weekly morning microstructure observations covering the destratification period (July 2015, February 2016) at a coastal site in the western Mediterranean Sea, influenced by freshwater runoffs. Estimated with bulk parameters from the public re-analyzed dataset ERA5, the Ekman layer, and the convective penetration depth scale with the mixed layer depth (MLD) with a good agreement. Below the MLD, peaks of ε are observed in the baroclinic layers that progressively overlap with the bottom layer, where repeated near-bottom turbidity peaks provide evidence of sediment resuspension, suggesting energetic processes within the bottom boundary layer. In the subsurface, moderate values (10−9 to 10−8 W kg−1) are observed, following a Burr type XII distribution. Significant correlation with ε at MLD is obtained with a model combining the effects of wind, wind–wave, and convection, highlighting a calm sea bias in our data, plus a sunrise bias when morning buoyancy fluxes are stabilizing. Another correlation, obtained from a pure-wind estimation 18 h before, suggests the role of wind in generating internal waves in the stratified layers, thus, impacting mixing intensity.