Vertical Dispersion Research Articles

An analytical solution for contaminant extraction from multilayered soil using PVD-enhanced system

Prefabricated vertical drains (PVDs) have been employed to enhance the in situ remediation of contaminated fine-grained soils. Subsurface heterogeneity can interfere with the distribution and extraction of contaminants during the remediation process. In the present study, an analytical solution for contaminant extraction from multilayered soil using a PVD-enhanced system is developed based on an equivalent planar two-dimensional model. The analytical solution is derived using a procedure that combines the Laplace transform, eigenfunction method and numerical Laplace inversion. The validity and accuracy of the solution are verified by comparison with an existing analytical solution and the results obtained using a numerical model. The effects of several key parameters on the performance of a PVD remediation system in a triple-layered contaminated soil are evaluated. The results indicate that the remediation efficiency for clay layers decreases with increasing hydraulic conductivity or thickness of the sand layer. The PVD remediation system may be unfeasible for contaminated sites with high subsurface heterogeneity caused by permeability contrast. The remediation process for clay layers can be accelerated by increasing the clay vertical dispersivity.

Observations and parameterization of the effects of barrier height and source-to-barrier distance on concentrations downwind of a roadway

New results are presented from wind tunnel studies performed at the United States Environmental Protection Agency (U.S. EPA), which include cases with solid roadside barriers of varying heights and cases with varying distances between the line source (roadway) and a 6-m-tall barrier. The Source-to-Barrier Distance cases include seven lanes of traffic with each lane acting as an independent source of continuous emissions along a line (i.e., line source). A mixed-wake algorithm that accounts for barrier effects within a steady-state air dispersion model was updated based on the recent wind tunnel studies. To study the effects of a solid roadside barrier, varying barrier heights and varying distances between the line source and barrier were modeled with the U.S. EPA regulatory air dispersion model AERMOD (v. 21112) using the line-source option that includes an experimental barrier option (RLINEXT). The mixed-wake algorithm reproduced the shape of the vertical concentration profiles observed in the wind tunnel data, including the uniform concentration profile from the ground vertically to a height somewhat greater than the height of the barrier. The algorithm responded appropriately to changes in barrier height and source-to-barrier distance, producing greater reductions in ground-level concentrations for taller barriers and for shorter source-to-barrier distances. Additionally, a rule of thumb that approximates the effect of a downwind barrier was formulated by converting an estimated vertical dispersion into an additional travel distance. The wind tunnel results, the update to the mixed-wake algorithm, and a comparison of the two data sets are described in this paper.

Comparative study of two software for the detection of cephalometric landmarks by artificial intelligence

Manual, tedious cephalometric analyzes of a lack of productivity (errors in plotting and measurement) making the prospect of a fully automated algorithm turning out attractive. The objectives of the study were to evaluate the positioning (accuracy and precision) of common landmarks by two software programs offering detection by artificial intelligence (WebCeph™ and DentaliQ®) compared to a manual reference and then to the comparators. 68 lateral cephalograms were selected, 22 landmarks were distributed manually and then the differences between this gold standard and the points detected by each software were measured, as well as the success detection rate (SDR). Statistical analysis was carried out by “confidence ellipses” and two-tailed t-test (p-value of 5%). In terms of accuracy, WebCeph™ and DentaliQ® show a 2 mm SDR of 57.2% and 66.5% respectively. In terms of trueness, the best results are obtained for S, Na and the incisal edges. Large random errors are found for the points Po, So, ENA, ENP, Ba and Go. Other points like Pog and B show a large vertical dispersion. Overall, a slight advantage goes to DentaliQ® even if the difference is not significant. The detection precision still seems insufficient for an utilization without human supervision. The results are promising on the detection of certain points. The artificial intelligence saves time for the clinician but the change of positioning of points should still be possible. Advances are rapid and will probably be soon for an effective clinical use.

Enhance the thermal conductivity and mechanical properties of CF/PPBESK thermoplastic composites by growth ZnO nanowires with tunable length and diameter on prepreg

This study proposes a simple and effective way to modify prepreg by vertically aligned ZnO nanowires (ZnO NWs) with tunable length and diameter to enhance the thermal conductivity and mechanical properties of Carbon fiber/Copoly (phthalazinone ether sulfone ketone) (CF/PPBESK) composites. The effect of the morphology of ZnO NWs on the thermal conductivity and mechanical performance of composites were investigated. Observed by scanning electron microscopy, the surface of the prepregs and the cross-section of the composites showed uniform vertical ZnO NWs dispersion and strong fiber-resin adhesion. The result indicated that the thermal conductivity of ZnO NWs/CF/PPBESK composites were increased by 47.4% after ZnO NWs introducing. Moreover, the flexural strength, compressive strength and ILSS of ZnO NWs-modified composites were increased by 16.5%, 54.7% and 24.1%. The high temperature mechanical properties of ZnO NWs/CF/PPBESK composites were also improved, which suggested that introduction of ZnO NWs between prepreg layers was an effective way to construct structure/function integrated composites.

First Results from SMAUG: Insights into Star Formation Conditions from Spatially Resolved ISM Properties in TNG50

Abstract Physical and chemical properties of the interstellar medium (ISM) at subgalactic (∼kiloparsec) scales play an indispensable role in controlling the ability of gas to form stars. In this paper, we use the TNG50 cosmological simulation to explore the physical parameter space of eight resolved ISM properties in star-forming regions to constrain the areas of this hyperspace where most star-forming environments exist. We deconstruct our simulated galaxies spanning a wide range of mass (M ⋆ = 107–1011 M ⊙) and redshift (0 ≤ z ≤ 3) into kiloparsec-sized regions and statistically analyze the gas/stellar surface densities, gas metallicity, vertical stellar velocity dispersion, epicyclic frequency, and dark-matter volumetric density representative of each region in the context of their star formation activity and environment (radial galactocentric location). By examining the star formation rate (SFR) weighted distributions of these properties, we show that stars primarily form in two distinct environmental regimes, which are brought about by an underlying bicomponent radial SFR profile in galaxies. We examine how the relative prominence of these regimes depends on galaxy mass and cosmic time. We also compare our findings with those from integral field spectroscopy observations and find similarities as well as departures. Further, using dimensionality reduction, we characterize the aforementioned hyperspace to reveal a high degree of multicollinearity in relationships among ISM properties that drive the distribution of star formation at kiloparsec scales. Based on this, we show that a reduced 3D representation underpinned by a multivariate radius relationship is sufficient to capture most of the variance in the original 8D space.

Numerical analysis of wood air gasification in a bubbling fluidized gasifier with reactive charcoal as bed material

In this work, a reactive multiphase particle-in-cell model based on the Eulerian-Lagrangian framework is developed to numerically investigate the wood gasification process in a three-dimensional air-blown bubbling fluidized bed gasifier with the reactive charcoal as bed material. After the model validation, the impacts of gas velocity and initial bed height on the physical and thermophysical properties of gas-solid reacting flow are studied. The results show that lighter particles suspend at the upper part of the dense region with a larger rising velocity due to the density- and size-induced segregation. The vertical dispersion of both particle species is two orders of magnitude larger than the horizontal one. Large heat transfer coefficient (HTC) of solid phase appears in the rising path of biomass. Superficial gas velocity significantly affects the composition and the thermal properties of gas species. Heavy charcoal particles mainly distribute in the dense region with a high temperature and small HTC. Enlarging the superficial gas velocity increases the CO2 concentration whereas decreases the yields of combustible gas species. Initial bed height exerts an insignificant effect on the thermal property of gas phase, especially in the dense region.

Stochastic Air Quality Dispersion Model for Defining Queuing Ships Seaport Location

This work develops a stochastic air quality dispersion to predict the pollution concentration originating from ships queuing in a seaport. The Gaussian dispersion model for five ships operating in the Black Sea queuing in the front of the port of Varna as sources of gas emission of NOx, SOx and PM10 is used to define the air pollution concentration at receptors (crowded areas of the port and other reference points) and consequently the distance to the seaport queuing location. Uncertainties, which are inherent in the input data and mathematical model, are accounted for to estimate the propagating uncertainties of the emission concentration at the receptors accounting for the wind speed, horizontal and vertical dispersion parameters as a function of the geographical location of the emission sources (ships), effective emission height and weather conditions. The estimated uncertainties of the air quality prediction are of significant importance for the decision-making on the regulatory purposes, and the probability of exceeding the threshold limits needs to be quantified. The most expected value and the probability of exceeding the acceptable limits of pollution concentration are defined by employing the first-order reliability method. The target reliability level is defined as the failure cause and mode used for identifying the safety calibration factors that may be employed for defining the most suitable location of the ship queuing seaport. Several conclusions about the applicability of the developed stochastic model and its use for regulatory purposes are also provided.

Vertical dispersion mechanism of long-range transported dust in Beijing: Effects of atmospheric turbulence

An extreme dust storm hit North China from March 14 to 16, 2021. With the enhanced observations in Beijing, the vertical dispersion of long-range transported dust was investigated from the perspective of atmospheric turbulence. A framework was developed by combining two types of turbulence intermittency parameter to distinguish intermittent or continuous turbulence; thus, the evolution of turbulence and its roles in dust dispersion were clearly illustrated on March 15, 2021. Initially, turbulence remained in the long quiescent period and turbulent exchange was suppressed significantly, which negligibly increased the dust mass concentration in the lower atmosphere, despite the dust mass being located at 300 to 800 m. Then, a short turbulence burst occurred as the cold front approached Beijing, and the elevated dust was mixed downward intensely and rapidly, leading to a sharp increase in the near-surface dust mass concentration. Finally, continuous turbulence dominated and diffused dust upward when the cold front fully occupied Beijing. Furthermore, the dissimilarity between the turbulent transport of dust and momentum-heat depends on the presence of dust sources (e.g., elevated dust mass and advection). When dust sources exist, there is efficient dust transport by large-scale turbulence, and thus the transport of dust and momentum-heat is similar. However, when there is no dust source, dust particles do not follow the air mass for small-scale turbulence and exhibit strong random movements, which confounds downgradient transport by large-scale turbulence and leads to low dust transport efficiency. In this condition, the conventional flux-gradient method is not applicable to estimate the dust flux especially by replacing the diffusion coefficient or universal function of dust mass concentration with that of momentum or heat.

The dynamics of three nearby E0 galaxies in refracted gravity

We tested whether refracted gravity, a theory of modified gravity that describes the dynamics of galaxies without the aid of dark matter, can model the dynamics of the three massive elliptical galaxies, NGC 1407, NGC 4486, and NGC 5846, out to ∼10Re, where the baryonic mass component fades out and dark matter is required in Newtonian gravity. We probed these outer regions with the kinematics of the globular clusters provided by the SLUGGS survey. Refracted gravity mimics dark matter with the gravitational permittivity, a monotonic function of the local mass density depending on three parameters,ϵ0,ρc, andQ, which are expected to be universal. Refracted gravity satisfactorily reproduces the velocity dispersion profiles of the stars and red and blue globular clusters, with stellar mass-to-light ratios in agreement with stellar population synthesis models, and orbital anisotropy parameters consistent with previous results obtained in Newtonian gravity with dark matter. The sets of the three parameters of the gravitational permittivity found for each galaxy are consistent with each other within ∼2σ. We compare the mean {ϵ0,Q,log10(ρc[g cm−3])} = {0.089−0.035+0.038, 0.47−0.21+0.29, −24.25−0.20+0.28} found here with the means of the parameters required to model the rotation curves and vertical velocity dispersion profiles of 30 disk galaxies from the DiskMass Survey (DMS):ρcandQagree within 1σwith the DMS values, whereasϵ0agrees within 3σ. This agreement suggests that ellipticals and disk galaxies allow for common values of the parameters of the permittivity and supports the universality of the permittivity function.

Droplet Size Distribution Effect on the Vertical Dispersion of Spilled Oil Due to Regular Non-Breaking Waves

Droplet Size Distribution Effect on the Vertical Dispersion of Spilled Oil Due to Regular Non-Breaking Waves

Pollutant Concentration Changes During the COVID-19 Lockdown in Barcelona and Surrounding Regions: Modification of Diurnal Cycles and Limited Role of Meteorological Conditions

One of the consequences of the COVID-19 lockdowns has been the modification of the air quality in many cities around the world. This study focuses on the variations in pollutant concentrations and how important meteorological conditions were for those variations in Barcelona and the surrounding area during the 2020 lockdown. Boundary-layer height, wind speed, and precipitation were compared between mid-March and April 2016–2019 (pre-lockdown) and the same period in 2020 (during lockdown). The results show the limited influence of meteorological factors on horizontal and vertical dispersion conditions. Compared with the pre-lockdown period, during lockdown the boundary-layer height slightly increased by between 5% and 9%, mean wind speed was very similar, and the fraction of days with rainfall increased only marginally, from 0.33 to 0.34, even though April 2020 was extremely wet in the study area. Variations in nitrogen dioxide (hbox {NO}_{{2}}), particulate matter with a diameter less than 10 {mu }m (PM10), and ozone (hbox {O}_{{3}}) concentrations over a 10-year period showed a 66% reduction in hbox {NO}_{{2}}, 37% reduction in PM10, and 27% increase in hbox {O}_{{3}} at a traffic station in Barcelona. The differences in the daily concentration cycle between weekends and weekdays were heavily smoothed for all pollutants considered. The afternoon hbox {NO}_{{2}} peak at the traffic station was suppressed compared with the average daily cycle. The analysis of ozone was extended to the regional scale, revealing lower concentrations at rural sites and higher ones in urban zones, especially in Barcelona and the surrounding area. The results presented not only complement previous air quality COVID-19 lockdown studies but also provide insights into the effects of road-traffic reduction.

CFD study of the reactive gas-solid hydrodynamics in a large-scale catalytic methanol-to-olefin fluidized bed reactor

Lacking the understanding of multiphase flow in the fluidized bed methanol-to-olefin (MTO) process hinders the reactor design, operation, and optimization. Accordingly, a three-dimensional multiphase particle-in-cell model is established to study hydrodynamics and thermochemical characteristics during the MTO process in a fluidized bed reactor. After model validation, the influences of several critical operating parameters on reactor performance are discussed. The results show that particles in the medium part and freeboard of the reactor have heterogeneous velocity, temperature, and heat transfer coefficient (HTC) distributions. Thermal quantities of gas and solid phases are uniformly distributed in the medium part and freeboard of the reactor. The particle-averaged HTC under ranges from 60 to 120 W/(m2·K). Increasing wall temperature enlarges the particle HTC due to the enhanced exothermic reactions. Decreasing the particle diameter gives rise to a larger particle HTC. The vertical particle dispersion coefficient (Dz) is in the range of 0.01 m2/s to 0.03 m2/s. Methanol converts into olefin in a short period. Increasing methanol to catalyst ratio and wall temperature increases olefin including C2H4, C3H6, C4H8, and C5H10, and promotes the gas thermal properties. Particles with multi-sizes show a better MTO conversion performance than those with mono-sizes regarding the particle HTC and gas products.

A microscopic study on the mixing process of binary solids in bubbling fluidized bed

A novel method for measuring the micro mixing ratio of binary solids in dense fluidizations is developed. The mixing process within a bubbling fluidized bed that can be assumed as one mixing cell is resolved. Dispersion coefficient and mixing index methods are applied to characterize the mixing process. Results show that diffusion has an important effect on mixing at the bottom and top of the fluidized bed. Meanwhile, convection is the principal mechanism of mixing at the center. The lateral micro dispersion coefficient is between 0.005 m/s and 0.03 m/s. The vertical micro dispersion coefficient is approximately twice as that in the lateral direction. A new mixing index is proposed to evaluate the micro mixing quality of binary solids. The time required to reach uniform mixing in the lateral direction is more than twice as that in the vertical direction.

Characterizing epochs of star formation across the Milky Way disc using age–metallicity distributions of GALAH stars

ABSTRACT We provide a detailed map of the ages and metallicities of turn-off stars in the Milky Way disc based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age–metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way. In the first phase, inner disc stars form along a single age–metallicity sequence and are today kinematically hot. The end of this phase is marked by a local minimum in the inner disc age distribution 10 Gyr ago. At this time, we find the stellar populations to transition from high to low alpha-element abundances and from high to low vertical velocity dispersion. In the second phase, stars form across the disc with outwardly decreasing metallicity. In this phase, inner disc stars form at supersolar metallicities in a continuation of the early age–metallicity relation, while outer disc stars begin forming at metallicities at least 0.5 dex lower. Finally, the third phase is associated with a recent burst of star formation across the local disc marked by a local minimum in the age–metallicity distribution 4–6 Gyr ago. Future quantitative comparisons between the observed age–metallicity distribution and those of simulated galaxies could help constrain the processes driving each of the star formation phases.

Dispersion and Stratification Dynamics in the Upper Sacramento River Deep Water Ship Channel

Hydrodynamics control the movement of water and material within and among habitats, where time-scales of mixing can exert bottom-up regulatory effects on aquatic ecosystems through their influence on primary production. The San Francisco Estuary (estuary) is a low-productivity ecosystem, which is in part responsible for constraining higher trophic levels, including fishes. Many research and habitat-restoration efforts trying to increase primary production have been conducted, including, as described here, a whole-ecosystem nutrient addition experiment where calcium nitrate was applied in the Sacramento River Deep Water Ship Channel (DWSC) to see if phytoplankton production could be increased and exported out of the DWSC. As an integral part of this experiment, we investigated the physical mechanisms that control mixing, and how these mechanisms affect the strength and duration of thermal stratification, which we revealed as critical for controlling phytoplankton dynamics in the relatively turbid upper DWSC. Analysis of a suite of mixing mechanisms and time-scales show that both tidal currents and wind control mixing rates and stratification dynamics in the DWSC. Longitudinal and vertical dispersion increased during periods of high wind, during which wind speed influenced dispersion more than tidal currents. Thermal stratification developed most days, which slowed vertical mixing but was rapidly broken down by wind-induced mixing. Stratification rarely persisted for longer than 24 hours, limiting phytoplankton production in the study area. The interaction between physical mechanisms that control mixing rates, mediate stratification dynamics, and ultimately limit primary production in the DWSC may be useful in informing habitat restoration elsewhere in the Delta and in other turbid aquatic environments.

The Compatibility between the Takeover Process in Conditional Automated Driving and the Current Geometric Design of the Deceleration Lane in Highway

In recent years, the takeover process of conditional automated driving has attached a great deal of attention. However, most of the existing research has focused on the effects of human-machine interactions or driver-related features (e.g., non-driving-related tasks), while there is little knowledge about the compatibility between the takeover process and existing road geometric design. As there is a high possibility that drivers must take over the vehicle before they diverge from the mainline of the highway, this explanatory study aimed to examine the compatibility between the takeover process and the current deceleration lane geometric design. The distribution range of existing deceleration lanes’ lengths were obtained through a geo-based survey. Nine scenarios were recreated in the driving simulator which were designed with various deceleration lane lengths and driving modes (different takeover time budgets and manual driving as the baseline group). A total of 31 participants were recruited to take part in the experiment, their gaze behaviors were recorded simultaneously. Results showed that, compared with manual driving, both drivers’ horizontal and vertical gaze dispersion increased, while drivers adopted higher deceleration in the mainline and merged into the deceleration lane later under takeover conditions. Moreover, a longer deceleration lane could benefit vehicle control. However, its marginal effect was reduced with the increase of deceleration lane length. These findings can help automated vehicle manufacturers design dedicated takeover schemes for different deceleration lane lengths.

Large eddy simulation of film cooling from cylindrical holes partially blocked by CaO-MgO-Al2O3-SiO2

CaO-MgO-Al2O3-SiO2 (CMAS) melting and then sticking in the film cooling holes is one of the important factors causing the cooling performance degradation of gas turbines. Large eddy simulation was used to study the unsteady flow physics, mixing heat transfer, and film cooling performance degradation of film cooling under the synergistic effect of typical blowing ratios (0.5 ≤ M ≤ 1.5) and blockage levels (0 ≤ H/D ≤ 0.75) and a particle deposition model was developed to predict the blockage characteristics. The results show that the deposition efficiency of CMAS is negatively correlated with the blowing ratio, and the CMAS blockage level increases nonlinearly with the service time. The film cooling effectiveness degradation rate of blocked cylindrical holes can be described by effective momentum flux ratio. With the increase of blockage and blowing ratio, the optimal effective momentum flux ratio increases from 0.14 to about 0.2, and the maximum cooling performance degradation rate reaches 95%. The blockage makes the coherent structures of film cooling more complex and disordered. The evolution of hairpin vortices and counter-rotating vortex pairs in spatial affects vertical mixing and lateral dispersion. The aggravation of hot-gas entrainment, coolant mixing, and flow separation are the root causes of the deterioration of cooling performance.

Sea ice presence is linked to higher carbon export and vertical microbial connectivity in the Eurasian Arctic Ocean

Arctic Ocean sea ice cover is shrinking due to warming. Long-term sediment trap data shows higher export efficiency of particulate organic carbon in regions with seasonal sea ice compared to regions without sea ice. To investigate this sea-ice enhanced export, we compared how different early summer phytoplankton communities in seasonally ice-free and ice-covered regions of the Fram Strait affect carbon export and vertical dispersal of microbes. In situ collected aggregates revealed two-fold higher carbon export of diatom-rich aggregates in ice-covered regions, compared to Phaeocystis aggregates in the ice-free region. Using microbial source tracking, we found that ice-covered regions were also associated with more surface-born microbial clades exported to the deep sea. Taken together, our results showed that ice-covered regions are responsible for high export efficiency and provide strong vertical microbial connectivity. Therefore, continuous sea-ice loss may decrease the vertical export efficiency, and thus the pelagic-benthic coupling, with potential repercussions for Arctic deep-sea ecosystems.

H i 21 cm observation and mass models of the extremely thin galaxy FGC 1440

ABSTRACT We present observations and models of the kinematics and distribution of neutral hydrogen (H i) in the superthin galaxy FGC 1440 with an optical axial ratio a/b = 20.4. Using the Giant Meterwave Radio telescope (GMRT), we imaged the galaxy with a spectral resolution of 1.7 km s−1 and a spatial resolution of 15${_{.}^{\prime\prime}}$9 × 13${_{.}^{\prime\prime}}$5. We find that FGC 1440 has an asymptotic rotational velocity of 141.8 km s−1. The structure of the H i disc in FGC 1440 is that of a typical thin disc warped along the line of sight, but we cannot rule out the presence of a central thick H i disc. We find that the dark matter halo in FGC 1440 could be modelled by a pseudo-isothermal (PIS) profile with $\\ R_{\rm c}/ R_{\rm d} \lt 2$, where Rc is the core radius of the PIS halo and Rd the exponential stellar disc scale length. We note that in spite of the unusually large axial ratio of FGC 1440, the ratio of the rotational velocity to stellar vertical velocity dispersion, $\frac{V_{\rm Rot}}{\sigma _{z}} \sim 5 - 8$, which is comparable to other superthins. Interestingly, unlike previously studied superthin galaxies which are outliers in the log10(j*) − log10(M*) relation for ordinary bulgeless disc galaxies, FGC 1440 is found to comply with the same. The values of j for the stars, gas, and the baryons in FGC 1440 are consistent with those of normal spiral galaxies with similar mass.

Atmospheric response to the annular solar eclipse of 26 December 2019 over Cochin, India

• Atmospheric response to annular solar eclipse of December 2019. • Drastic reduction in incoming solar radiation and variations in meteorological variables. • Mean PBL and Tropopause Heights were reduced by 50% and 5.5%. • Detected the presence of internal gravity waves with periodicities of 40–60 min. • Study useful for radiative transfer calculation and also for testing numerical models. The rapid response of the atmosphere to the reduction in solar radiation during the annular solar eclipse on 26th December 2019 with maximum obscurity of 91.16% over Cochin, located in the southwest peninsular India, has been investigated. A suite of instruments encompassing an advanced VHF wind profiling Radar operating at 205 MHz, GPS radiosonde, and automatic weather station was employed to record the temporal and vertical variations in various meteorological parameters. Compared to the corresponding values averaged for two control days neighboring the eclipse day, the temperature, relative humidity, net radiation, pressure and wind speed at the surface were altered by −4.0 °C, +39.6%, −383.0 Wm −2 , +0.62 mb, and −2.6 ms −1 , respectively. The corresponding percentage variations are −13.6%, +71.0%, −67.0%, +0.06%, and −99.0% during the maximum phase of the eclipse, and approached close to the control-day values within about 2 h. Multiple temperature inversions as large as 1 °C were observed up to a height of about 7.3 km. The heights of mean planetary boundary layer (PBL) and tropopause were decreased by about 355 m (−50%) and 900 m (−5.5%), respectively during the peak of obscuration. Meanwhile, the vertical profiles of both the horizontal and vertical wind velocities demonstrate substantial reduction. The vertical wind dispersion, which characterizes the fluctuations in vertical air motion, was reduced by 34% in the PBL compared to its corresponding values on the control days. Subsequently, wavelet spectral analysis of the vertical wind yields a quasi-periodic oscillation indicating the presence of internal gravity waves with periodicities of 40–60 min in the lower altitudes up to 3 km during the eclipse day. Besides reporting the characteristic variations in various atmospheric parameters, the present study reveals the height-time variations in the vertical winds, a vital parameter of significance in the studies of convection, turbulence, and atmospheric waves.