Horizontal And Vertical Research Articles

Dynamic Simulation of the Leaf Mass per Area (LMA) in Multilayer Crowns of Young Larix principis-rupprechtii.

Leaf mass per area (LMA) is a key structural parameter that reflects the functional traits of leaves and plays a vital role in simulating the material and energy cycles of plant ecosystems. In this study, vertical whorl-by-whorl sampling of LMA was conducted in a young Larix principis-rupprechtii plantation during the growing season at the Saihanba Forest Farm. The vertical and seasonal variations in LMA were analysed. Subsequently, a predictive model of LMA was constructed. The results revealed that the LMA varied significantly between different crown whorls and growing periods. In the vertical direction of the crown, the LMA decreased with increasing crown depth, but the range of LMA values from the tree top to the bottom was, on average, 30.4 g/m2, which was approximately 2.5 times greater in the fully expanded phase than in the early leaf-expanding phase. During different growing periods, the LMA exhibited an allometric growth trend that increased during the leaf-expanding phase and then tended to stabilize. However, the range of LMA values throughout the growing period was, on average, 40.4 g/m2. Among the univariate models, the leaf dry matter content (LDMC) performed well (adjusted determination coefficient (Ra2) = 0.45, root mean square error (RMSE) = 13.48 g/m2) in estimating the LMA. The correlation between LMA and LDMC significantly differed at different growth stages and at different vertical crown whorls. The dynamic predictive model of LMA constructed with the relative depth in the crown (RDINC) and date of the year (DOY) as independent variables was reliable in both the assessments (Ra2 = 0.68, RMSE = 10.25 g/m2) and the validation (absolute mean error (MAE) = 8.05 g/m2, fit index (FI) = 0.682). Dynamic simulations of crown LMA provide a basis for elucidating the mechanism of crown development and laying the foundation for the construction of an ecological process model.

Prediction of horizontal and vertical turning maneuvers of a generic submarine model by closed-form solutions and CFD

Turning maneuvering performance of a generic submarine in both the horizontal and vertical planes is investigated using closed-form (analytical) solutions and the Computational Fluid Dynamics (CFD) method. The aim is to provide a simple yet improvable method throughout the design phase of an underwater vehicle. Both the turning circle maneuver in the horizontal plane and the rising maneuver in the vertical plane are performed. Vehicle trajectories are obtained using closed-form solutions and a linearized maneuvering model with a limited set of hydrodynamic coefficients computed from the CFD model. The derivation of the closed-form solution is based on the basic mechanical principles of steady circular motion, while the hydrodynamic coefficients are determined via steady CFD simulations using a single grid topology. The steady turning diameter serves as the figure of merit in a turning circle maneuver. For the rising maneuver, trajectories predicted by both methods are directly compared. The methods are found to be in good agreement for both maneuvers. Maneuvering predictions made with the linear coefficient set are also open to development. As the design of the submarine evolve, nonlinear and coupled effects can be included in the mathematical model by incorporating related hydrodynamic coefficients to obtain more accurate results.

Bobble Head Doll Syndrome Revealing a Suprasellar Arachnoid Cyst : Case Report

Introduction Bobble head doll syndrome (BHDS) is a rare neurological syndrome that appears in childhood. It is characterized by abnormal movements of the head, most commonly in an up-and-down motion ("yes yes") and rarely in the horizontal plane ("no no"). We report a case of BHDS revealing a large suprasellar arachnoid cyst. Observation A 6-year-old child was brought by his parents to a neurology consultation for abnormal head movements, which most frequently occurred in an upward and downward direction, but disappeared during sleep. These abnormal movements had been progressively worsening over the course of approximately one year. Clinical examination revealed a decrease in visual acuity in both eyes, with papillary hyperemia on fundoscopy and discreet ataxia in walking. Magnetic resonance imaging (MRI) revealed a compressive suprasellar arachnoid cyst with passive biventricular hydrocephalus. Surgical treatment with neuro-endoscopy led to a remarkable regression of abnormal head movements and ataxia in the immediate postoperative period, with complete disappearance in the long term. Conclusion Bobble head doll syndrome is a potentially "curable" entity, and diagnosis is provided by cerebral MRI.

Construction of line Layout Model Based on Geometric Deduction and Constrained Heuristic Search

Based on problem B of the National Mathematical Contest in Modeling for College Students in 2023, this paper establishes a model through geometric deductive deduction, and establishes and solves an optimal model of survey line layout through constrained heuristic algorithm. In problem 1, a mathematical model of coverage width and overlap rate is established based on triangle relation and triangle sine theorem by finding the mathematical relationship between target quantity and known quantity. In problem 2, the angle between the known direction of the survey line and the projection of the normal direction of the submarine slope on the horizontal plane is . We can imagine a surface perpendicular to the direction of the measurement line, and then find the slope of the imaginary surface according to the geometric relationship, and replace the slope Angle of problem 1 with the imaginary slope Angle to obtain the mathematical model of the coverage width. Based on this, the constraints of the Angle and overlap rate of the line are added, and the problem 3 is simplified into the optimization problem of multiple routes in problem 2. Finally, by changing the parameter setting of slope Angle in the model, the sensitivity analysis is carried out, and it is found that the model is stable and reliable.To sum up, the problems from one to four are gradually deepened and progressively advanced, and the development of Marine survey field is facilitated by establishing a model of depth survey line layout.

Enhancing mechanical properties and defects elimination in 2024 aluminum alloy through interlayer friction stir processing in wire arc additive manufacturing

In this study, a hybrid wire arc additive manufacturing (WAAM) and interlayer friction stir processing (IFSP) approach was utilized to enhance the quality of 2024 aluminum alloy components. The defects characteristic, microstructure evolution, and mechanical properties of the fabricated components and after T6 heat treatment were analyzed systematically. Our analysis reveals that IFSP can break and dissolve the eutectic phases, significantly reduce porosity defects and refine the grain size of the as-deposited materials, thus improving the overall mechanical properties. Notably, compared to the WAAM as-deposited component, the yield strength (YS) and ultimate tensile strength (UTS) in the top-layer stir zone (SZ) of IFSP component increased from 154 ± 3 to 267 ± 2 MPa, and from 258 ± 12 to 360 ± 3 MPa, respectively. However, in the middle-layer SZ, S-phase precipitation and coarsening induced by thermal cycling during additive manufacturing slightly reduced the tensile properties. Post-T6 heat treatment led to uniformly distributed properties in the IFSP component along both horizontal and vertical directions, with the YS, UTS, and elongation (EL) averaging 353 ± 9 MPa, 470 ± 4 MPa, and 10.5 ± 1.6%, closely matching those of wrought counterparts. The significant improvements in mechanical properties are primarily attributed to the elimination of porosity and precipitation of fine needle-like S-phase. This research not only demonstrates the potential of IFSP in enhancing the mechanical properties of WAAM-fabricated 2024 aluminum alloy but also offers a promising technique for producing high-quality components suitable for high-performance aerospace applications.

Transportation of melting heat in stratified Jeffrey fluid flow with heat generation and magnetic field

In current years, storage of energy is a challenging task for the scientists and researchers. So, they are interested to develop some extra ordinary techniques of energy storage. Thus, our main theme here is to focus on the latent heat energy (melting heat) which is more economical and sustainable. Transportation of melting heat in quadratic stratified Jeffrey fluid flow in the vicinity of stagnation point is scrutinized. The flow is deformed by linear stretchable sheet. Characteristics of heat transportation are scrutinized through viscous dissipation and heat generation or absorption. Constant magnetic field is implemented to electrically conducting fluid in vertical direction. The arising governing equations are converted in the non-dimensional state through suitable transformations. Homotopic technique is utilized for simulation of solutions. Graphical behavior of velocity and temperature fields is investigated corresponding to relevant parameters. As a conclusion, higher amount of energy can be achieved as melting phenomenon enhances, and also results in low temperature. Further, dominant stratification decays the temperature field. Current study will play key role in industrial liquids like polymer solutions to make high quality fiberglass, paints, silicone heat valves etc. This study will also deliberate efficiently for the storage of energy through phase change procedure i.e., melting phenomenon.

Mechanical behaviors of ballastless track under temperature and vehicle loads in high geo-temperature tunnel

To explore the temperature field, temperature effect and mechanical behaviors of the track structure under combined load in high geo-temperature tunnel, the temperature field test platform is built to simulate the conditions under which the track bottom is heated in high geo-temperature tunnel, and the temperature distribution of the track bed slab in the transverse, longitudinal, and vertical directions is investigated. Then, the numerical model is built to examine the displacement and stress of the track structure under temperature load and combined load consisting of temperature and static vehicle load. The results show that when the temperature load on the track bottom is 30 ℃, the vertical temperature gradient inside the slab is negative, with a maximum of 20 ℃/m, and the maximum temperature differences in the vertical, transverse, and longitudinal directions are 5 ℃, 3.25 ℃ and 2 ℃, respectively. The temperature deformation of the track bed slab is manifested as sinking in the middle and warping at the edge, with the maximum tensile stress occurring in the upper-middle region and the maximum compressive stress in the lower-middle region. Under the combined load, the most unfavorable position of the vehicle load is where the front wheel is in the center of the slab, and for every 5 tons increase in axle load, the maximum tensile stress of the slab increases by about 4%, and the maximum compressive stress increases by about 2%. The findings provide reference for the optimization design of track in high geo-temperature tunnel.

Observation on the tilt and decentration of multifocal intraocular lens with optic capture in Berger space for pediatric cataract.

This study aimed to observe the tilt and decentration of multifocal intraocular lens (IOL) with optic capture in Berger space within 2 years after pediatric cataract surgery. This is a prospective observational study. The implantation of multifocal IOL (Tecnis ZMB00) with optic capture in Berger space was performed on 33 patients (48 eyes) with pediatric cataract at Qingdao Eye Hospital. Tilt and decentration of IOL was measured using Scheimpflug system (Pentacam) at 1month and 2years postoperatively. All the multifocal IOLs were successfully implanted in Berger space with optic capture and no visually significant complications were detected during the follow-up. The mean tilt of IOLs was 2.779° ± 0.950° in the vertical plane and 2.399° ± 0.898° in the horizontal plane at 1month postoperatively, and the mean length of the decentration was 0.207 ± 0.081mm in vertical plane and 0.211 ± 0.090mm in the horizontal plane. Compared with 1month after surgery, the angle of tilt decreased by a mean of 0.192° and decentration increased by a mean of 0.014mm at the vertical meridian at 2 years postoperatively (P = 0.37 and P = 0.27, respectively), meanwhile, tilt increased by 0.265° and decentration increased by 0.012mm at the horizontal meridian (P = 0.11 and P = 0.22, respectively). The follow-up results suggest the tilt and decentration of multifocal IOL implantation with optic capture in Berger space remain stable in an acceptable range within 2years after cataract surgery in children above the age of 5. The study was approved by the Ethics Committee of Qingdao Eye Hospital, and registered on Chinese Clinical Trial Registry (ChiCTR identifier: 1900023155).

Study on the biodynamic characteristics and internal vibration behaviors of a seated human body under biomechanical characteristics.

To provide reference and theoretical guidance for establishing human body dynamics models and studying biomechanical vibration behavior, this study aimed to develop and verify a computational model of a three-dimensional seated human body with detailed anatomical structure under complex biomechanical characteristics to investigate dynamic characteristics and internal vibration behaviors of the human body. Fifty modes of a seated human body were extracted by modal method. The intervertebral disc and head motions under uniaxial white noise excitation (between 0 and 20Hz at 1.0, 0.5 and 0.5m/s2 r.m.s. for vertical, fore-aft and lateral direction, respectively) were computed by random response analysis method. It was found that there were many modes of the seated human body in the low-frequency range, and the modes that had a great impact on seated human vibration were mainly distributed below 13Hz. The responses of different positions of the spine varied greatly under the fore-aft and lateral excitation, but the maximum stress was distributed in the lumbar under different excitations, which could explain why drivers were prone to lower back pain after prolonged driving. Moreover, there was a large vibration coupling between the vertical and fore-aft direction of an upright seated human body, while the vibration couplings between the lateral and other directions were very small. Overall, the study could provide new insights into not only the overall dynamic characteristics of the human body, but also the internal local motion and biomechanical characteristics under different excitations.

Bilayer ion trap design for 2D arrays

Junctions are fundamental elements that support qubit locomotion in two-dimensional ion trap arrays and enhance connectivity in emerging trapped-ion quantum computers. In surface ion traps they have typically been implemented by shaping radio frequency (RF) electrodes in a single plane to minimize the disturbance to the pseudopotential. However, this method introduces issues related to RF lead routing that can increase power dissipation and the likelihood of voltage breakdown. Here, we propose and simulate a novel two-layer junction design incorporating two perpendicularly rotoreflected (rotated, then reflected) linear ion traps. The traps are vertically separated, and create a trapping potential between their respective planes. The orthogonal orientation of the RF electrodes of each trap relative to the other provides perpendicular axes of confinement that can be used to realize transport in two dimensions. While this design introduces manufacturing and operating challenges, as now two separate structures have to be precisely positioned relative to each other in the vertical direction and optical access from the top is obscured, it obviates the need to route RF leads below the top surface of the trap and eliminates the pseudopotential bumps that occur in typical junctions. In this paper the stability of idealized ion transfer in the new configuration is demonstrated, both by solving the Mathieu equation analytically to identify the stable regions and by numerically modeling ion dynamics. Our novel junction layout has the potential to enhance the flexibility of microfabricated ion trap control to enable large-scale trapped-ion quantum computing.

Back-trajectory analyses for evaluating the transboundary transport effect to the aerosol pollution in South Korea

This study performed a back-trajectory analysis to determine the influence of transboundary transport on the extent of aerosol pollution in South Korea, based on 5-year PM2.5 measurements (2015–2019) in five cities covering South Korea. A transboundary transport case was selected if a back trajectory passed over a dedicated region (BOX 1 and BOX 2) in the Yellow Sea. First, we found that the frequency of transboundary transport largely increases in the high pollution case, and this pattern is almost consistent for all months and all five cities, indicating the importance of investigating the horizontal direction of air mass movement associated with PM2.5, which has been discussed extensively in previous studies. In this study, we also examined the altitude change and straight moving distance (defined as travel distance) of back trajectories regarding the extent of local PM2.5. Consequently, we found that back trajectories in high aerosol pollution showed much lower altitudes and shorter travel differences, implying a significant contribution of surface emissions and stagnant air conditions to severe aerosol pollution. As a result, the local PM2.5 level was not significantly enhanced when the air mass passed over the Yellow Sea if transboundary transport occurred at high altitudes with rapid movement (i.e., high altitude and long travel distance back-trajectory). Based on these results, we suggest utilizing the combined information of the horizontal direction, altitude variation, and length of back trajectories to better evaluate transboundary transport.

Results of a comparative study of coulter groups of a seeder for strip sowing of grass seeds in the sod

For the effective use of sod seeders SDK in conditions of degraded forage lands, it is necessary to modernize the design of their coulter group to work in conditions of high soil moisture and increased content of plant residues in it. A method of strip sowing is proposed, which is based on the removal of the sowing working elements from under the casing of a milling furrow opener, and a design and technological scheme of the coulter group with a shoe opener mounted on a suspension mechanism in the form of torsion springs. The coulter group includes a mounting bracket on a seeder, a suspension mechanism, shoe openers, rollers, mechanisms for adjusting the position of coulters in the vertical and horizontal planes and the forces of deepening coulters and the pressure of rollers on the soil. Compared to the coulter group of SDK seeders, its weight (19.6 kg) is reduced by 3.8 kg while the total length of the seeder increases by 0.12 m. To assess the efficiency of the modernized coulter group of the sod seeder, experimental studies were carried out in the field, during which the quality indicators of seed placement were determined when using a serial coulter group of SDK seeders and a prototype coulter group. Comparative studies of coulter groups of a sod seeder showed that when sowing Eastern galega, the depth of seed placement complies with agrotechnical requirements and is: for the coulter group of SDK seeder – 19.4...22.4 mm, for the prototype - 18.6...19.5 mm, and for the prototype the value of the standard deviation is almost two times lower. The uniformity of the distribution of seeds over the width of the strip for the coulter group of the SDK seeder is 20.2...26.1 mm, for the prototype – 8.4...10.1 mm.

Distribution and Abundance of Solar Wind‐Derived Water in Chang'E‐5 Core Samples and Its Implications

AbstractKnowledge regarding the abundance and distribution of solar wind (SW)‐sourced water (OH/H2O) on the Moon in the shallow subsurface remains limited. Here, we report the NanoSIMS measurements of H abundances and D/H ratios on soil grains from three deepest sections of the Chang'E‐5 drill core sampled at depths of 0.45–0.8 m. High water contents of 0.13–1.3 wt.% are present on approximately half of the grain surfaces (topmost ∼100 nm), comparable to the values of Chang'E‐5 scooped soils. The extremely low δD values (as low as −995‰) and negative correlations between δD and water contents indicate that SW implantation is an important source of water beneath the lunar surface. The results are indicative of homogeneous distribution of SW‐derived water in the vertical direction, providing compelling evidence for the well‐mixed nature of the lunar regolith. Moreover, the findings demonstrate that the shallow subsurface regolith of the Moon contains a considerable amount of water.

A Multi-Satellite SBAS for Retrieving Long-Term Ground Displacement Time Series

Ground deformation is one of the crucial issues threatening many cities in both societal and economic aspects. Interferometric synthetic aperture radar (InSAR) has been widely used for deformation monitoring. Recently, there has been an increasing availability of massive archives of SAR images from various satellites or sensors. This paper introduces Multi-Satellite SBAS that exploits complementary information from different SAR data to generate integrated long-term ground displacement time series. The proposed method is employed to create the vertical displacement maps of Almokattam City in Egypt from 2000 to 2020. The experimental results are promising using ERS, ENVISAT ASAR, and Sentinel-1A displacement integration. There is a remarkable deformation in the vertical direction along the west area while the mean deformation velocity is −2.32 mm/year. Cross-validation confirms that the root mean square error (RMSE) did not exceed 2.8 mm/year. In addition, the research findings are comparable to those of the previous research in the study area. Consequently, the proposed integration method has great potential to generate displacement time series based on multi-satellite SAR data; however, it still requires further evaluation using field measurements.

Detecting Respondent Burden in Online Surveys: How Different Sources of Question Difficulty Influence Cursor Movements

Online surveys are a widely used mode of data collection. However, as no interviewer is present, respondents face any difficulties they encounter alone, which may lead to measurement error and biased or (at worst) invalid conclusions. Detecting response difficulty is therefore vital. Previous research has predominantly focused on response times to detect general response difficulty. However, response difficulty may stem from different sources, such as overly complex wording or similarity between response options. So far, the question of whether indicators can discriminate between these sources has not been addressed. The goal of the present study, therefore, was to evaluate whether specific characteristics of participants’ cursor movements are related to specific properties of survey questions that increase response difficulty. In a preregistered online experiment, we manipulated the length of the question text, the complexity of the question wording, and the difficulty of the response options orthogonally between questions. We hypothesized that these changes would lead to increased response times, hovers (movement pauses), and y-flips (changes in vertical movement direction), respectively. As expected, each manipulation led to an increase in the corresponding measure, although the other dependent variables were affected as well. However, the strengths of the effects did differ as expected between the mouse-tracking indices: Hovers were more sensitive to complex wording than to question difficulty, while the opposite was true for y-flips. These results indicate that differentiating sources of response difficulty might indeed be feasible using mouse-tracking.

Boussinesq-type equations of hydroelastic waves in shallow water

Accurate computation of hydroelastic waves in shallow water is critical because many hydroelastic wave applications are nearshores, such as sea-ice and floating infrastructures. In this paper, Boussinesq assumptions for shallow water are employed to derive nonlinear Boussinesq-type equations of hydroelastic waves, in which non-uniform distribution of structural stiffness and varying water depth are considered rigorously. Application of Boussinesq assumptions enables complicated three-dimensional problems to be reduced and formulated on the two-dimensional horizontal plane, therefore the proposed Boussinesq-type models are straightforward and versatile for a wide range of hydroelastic wave applications. Two configurations, a floating plate and a submerged plate, are studied. The first-order linear governing equations are solved analytically with periodic conditions assuming constant depth and uniform stiffness, and the linear dispersion relations are subsequently derived for both configurations. For flexural-gravity waves of a floating plate, unique behaviours of flexural-gravity waves different from shallow-water waves are discussed, and a generalized solitary wave solution is investigated. A nonlinear numerical solver is developed, and nonlinear flexural-gravity waves are found to have smaller wavelength and celerity than their linear counterparts. For hydroelastic waves of a submerged plate, dual-mode analytical solutions are discovered for the first time. Numerical computation has demonstrated that a plate with decreasing submerged depth is able to transfer wave energy from the deeper water to the surface layer.

Stiffness Anisotropy and Micro-Mechanism of Calcareous Sand with Different Particle Breakage Ratios Subjected to Shearing Based on DEM Simulations

Stress-induced anisotropy in calcareous sand can cause an uneven displacement in island reef engineering. In this study, stiffness, as a quantitative indicator, is explored to reveal the stress-induced anisotropy in calcareous sand. Based on the discrete element method, the stiffness anisotropic characteristics of calcareous sand during shearing, as well as the impact of particle breakage, are investigated by numerical simulations. Both the macro and micro responses, i.e., the maximum shear modulus, contact normal, strong and weak contact normal force, and the direction of particle breakage, are explored for calcareous sand with different particle breakage ratios. The results show that calcareous sand exhibits notable anisotropy during shearing, with the maximum shear modulus in the vertical direction (deviatoric stress direction) being significantly greater than that in the horizontal direction. Moreover, the higher the particle breakage rate, the lower the stiffness and its anisotropy. The micro-mechanism results indicate that the primary particle breakage during the shearing process occurs in the vertical direction. That is, the particle breakage weakens the strong contact force in the vertical direction, leading to a redistribution of the strong contact forces from the vertical direction to other directions. This redistribution mainly manifests in a decrease in the anisotropy of contact normal and contact vector within the sample, as well as a decrease in the proportion of strong contact forces in the overall contacts. This, in turn, reduces the shear strength and stiffness of calcareous sand, particularly in the vertical direction, and results in a decrease in the maximum shear modulus and its anisotropy. The maximum reduction can be up to 50% of the original value. These insights can provide a certain theoretical support for the uneven displacement and long-term stability of calcareous sand for islands and reefs.

Dynamics of Coalesced Droplet Jumping on Superhydrophobic Surface with Asymmetrically Wettable Ridge

Spontaneous detachment from superhydrophobic surfaces can be induced by the coalescence of two or more adjacent droplets. The phenomena have provided implications for the self-removal of droplets in the fields of self-cleaning, anti-icing, and heat transfer. However, many studies focus mainly on the theoretical jumping direction perpendicular to the substrate, although the velocity in the horizontal direction must be involved in practical applications due to various scenarios. This study analyzes numerically the effect of the distribution in ridge structure’s wettability on the performance of coalesced droplet jumping. The jumping dynamics are discussed for varying contact angle ratios and the aspect ratios of the ridge, which are the initial values for the current model. We obtain the height of the jumping and the offset distance in the horizontal direction under the several initial values. In addition, the characteristics of the asymmetric behavior are discussed based on the temporal evolution of the average velocities of the jumping droplets for each direction. Numerical results show that the horizontal offset distance is significantly pronounced at both the high asymmetry in wettability and the high aspect ratio of the ridge geometry. The phenomenon occurs when the droplet detaches from the ridge surface in the retraction process. We determine the role of the distribution within the ridge structure on its wettability, as well as the role of the aspect ratios of the ridge in facilitating the efficient transport of droplets.

Oral Habits in Childhood and Occlusal Pathologies: A Cohort Study.

To analyse the relationship between the different habits that occur in childhood and the different malocclusions in the three planes of space. A clinical examination of 106 children between 5 and 12 years of age was carried out and a survey validated by professors of the Faculty of Dentistry of the University of Seville was made for the parents in order to identify the habits and relate them to the possible malocclusions detected in the child's mouth. 72.64% of the sample presented a malocclusion in at least one of the three planes of space, with a similar distribution. When correlating the variables, statistically significant relationships were observed in the vertical plane with atypical swallowing (p = 0 < 0.05; V > 0.3) and lip sucking (p = 0 < 0.05; V > 0.3) and in the horizontal plane with oral breathing (p = 0 < 0.05; V > 0.3), atypical swallowing (p = 0 < 0.05; V < 0.3) and digital sucking (p = 0 < 0.05; V < 0.3). It has been observed that the prevalence and prolongation of habits in childhood is increasing, so it is essential to detect pernicious habits at an early age to prevent the establishment of malocclusions and to favour the correct craniofacial growth of the child.

Effect of diel light cycles on vertical migration patterns of Lepeophtheirus salmonis (Krøyer, 1837) copepodids measured in an in situ mesocosm

AbstractThe ectoparasitic salmon louse (Lepeophtheirus salmonis Krøyer, 1837) persists as a major hindrance for continued growth of the Norwegian salmon industry. Shielding technologies or management strategies are being used to reduce the likelihood of contact in the net pens between the salmon and the sea lice’s infectious copepodid stage. Knowledge about the vertical distribution and diel migration patterns of the planktonic sea lice stages are inevitably a premise for such water-depth-dependent avoidance technologies to be efficient; however, not many studies have investigated diel vertical migration patterns of sea lice in situ or in relevant scales. In this work, we aimed to monitor the diel migration of L. salmonis copepodids in the vertical plane without the influence of hydrographical forces, using sufficient water column depth of 11 m, natural thermoclines, and natural exogenous light conditions. We followed a cohort of copepodids over the course of 4 days and measured their vertical distribution in the water column twice per hour in a custom made mesocosm, using automatic particle detection and machine learning to analyse position and migration patterns. The L. salmonis copepodid population displayed reverse diel migration, and we found a statistically significant interaction between depth and time. During the day, copepodids were found in the upper 1 m of the water column, before the majority of the population descended to 1–2 m depth during night-time. A small fraction of the population remained in the upper part of the water column also during night-time. A significantly higher fraction of the copepodid population resided in the upper metre during daylight hours compared to other depths. These results could be utilised as input in sea lice dispersal models which are important management tools in today’s sea lice prevention strategies and regulatory frameworks.