Eddy Formation Research Articles

ENVIRONMENTAL PARAMETERS FOR CAMPUS OUTDOOR SPACE: A MICROCLIMATE ANALYSIS OF THE EASTERN MEDITERRANEAN UNIVERSITY (EMU) CAMPUS

ABSTRACT Open spaces—whether public, urban, or part of a campus—offer a variety of activities and opportunities to people. Therefore, open spaces should be considered a vital component of any built-up area and designed to meet the needs and address the comfort of potential users. Because of their presence in daily life and their preponderance of characteristics, open spaces have drawn the attention of many researchers, designers, and planners with varying perspectives. The current study takes a scientific approach to analyzing the environmental parameters of the Campus Outdoor Space (COS) in the case of the Eastern Mediterranean University (EMU). An extensive literature review supported the identification of seven important environmental parameters effective in the microscale analysis of a COS: geographical location, meteorological situation, urban form, surface materials, amount of vegetation and watershed, and anthropogenic pollution. Analysis of the environmental parameters called for a hybrid method that included a detailed field survey and the following set of simulations: sun-path, radiation, sky view factor, and turbulence analysis. The accuracy of the field survey directly contributed to the effectiveness of the simulations. Grasshopper® 3D software and Computational Fluid Dynamics were used to simulate the conditions of the EMU study area. The outcomes show that the spatial organization, building forms, and building orientation negatively affect the COS of EMU. In the Mediterranean climatic region of EMU, shade and flowing breezes greatly enhance comfort and usability of outdoor spaces from April to October. The massive form of buildings and minimal planning for effective building orientation to the sun increased heat storage capacity and neglected prevailing winds, resulting in flow separation and formation of eddies on the leeward side of buildings. These negatively influenced the microclimate, and thereby user comfort, at the core of the EMU’s main COS.

Ocean Dynamics and Topographic Upwelling Around the Aracati Seamount - North Brazilian Chain From in situ Observations and Modeling Results

The hydrodynamics and the occurrence of topographic upwelling around the northern Brazilian seamount chain were investigated. Meteorological and physical oceanographic data collected under the REVIZEE-NE Program cruises around the Aracati Bank, the major and highly productive seamount in the area, were analyzed and used to force and validate simulations using the 3D Princeton Ocean Model (3D POM). The Tropical Water mass in the top 150-m layer and the South Atlantic Central Water (SACW) beneath it and down to a depth of 670 m was present. The thickness of the barrier layer varied seasonally, being thinner (2 m) during the austral spring (October–December) and thicker (20 m) during the austral autumn (April–June) when winds were stronger. The surface mixed and isothermal layers in the austral winter (July–September) were located at depths of 84 and 96 m, respectively. During the austral spring, those layers were located at depths of 6 and 8 m, respectively. The mean wind shear energy was 9.8 × 10–4 m2 s–2, and the energy of the surface gravity wave break was 10.8 × 10–2 m2 s–2, and both served to enhance vertical mixing in the area. A permanent thermocline between the 70- and 150-m depths was present throughout the year. The isohaline distribution followed an isotherm pattern of variation, but at times, the formation of low-salinity eddies was verified on the bank slope. The 3D POM model reproduced the thermohaline structure accurately. Temperature and salinity profiles indicated the existence of vertical water displacements over the bank and along the direction of the North Brazil Current, which is the strongest western boundary current crossing the equatorial Atlantic. The kinematic structure observed in the simulations indicated vertical velocities of O (10–3 m.s–1) in the upstream region of the bank during austral winter and summer seasons. During the summer, the most important vertical velocities were localized below the lower limit of the euphotic zone; while during the austral winter, these velocities were within the euphotic zone, thereby favoring primary producers.

Zonal scale and temporal variability of the Asian monsoon anticyclone in an idealised numerical model

Abstract. The upper-level monsoon anticyclone is studied in a 3D dry dynamical model as the response of a background circulation without any imposed zonal structure to a steady imposed zonally confined heat source. The characteristics of the background circulation are determined by thermal relaxation towards a simple meridionally varying state, which gives rise to baroclinic instability if meridional gradients are sufficiently large. This model configuration allows the study of the dependence of the monsoon anticyclone response on characteristics of both the imposed heating and the background state, in particular including interactions between the anticyclone and the active dynamics on its poleward side in the form of a jet and baroclinic eddies. As characteristics of forcing and background state are varied a range of different behaviours emerges, many of which strongly resemble phenomena and features associated with the monsoon anticyclone as observed in re-analysis data. For a resting background state the time-mean anticyclone is highly extended in longitude to the west of the forcing region. When the active mid-latitude dynamics is included the zonal extent of the time-mean anticyclone is limited, without any need for the explicit upper-level momentum dissipation which is often included in simple theoretical models but difficult to justify physically. We further describe in detail the spontaneous emergence of temporal variability in the form of westward eddy shedding from the monsoon anticyclone for varying strength of the imposed heating. By varying the strength of the background mid-latitude dynamics we observe a transition of the system from a state with periodic westward eddy shedding to a state dominated by eastward shedding. The details of the time-mean structure and temporal evolution depend on the structure of the background flow, and for certain flows the monsoon anticyclone shows signs of both westward and eastward shedding.

Drivers of Phytoplankton Blooms in Hawaii: A Regional Model Study

AbstractThe region around the main Hawaiian Islands (MHI) is characterized by a permanent thermocline, and numerous processes have been proposed to facilitate phytoplankton blooms in this oligotrophic province. Here, we use a coupled physical‐biogeochemical model of the MHI to elucidate some of the different dynamics behind phytoplankton blooms. The model permits submesoscale processes and is integrated for the years 2010–2017 embedded in a physical state‐estimate reanalysis using nearly 50 million observations. Model results exhibit good agreement between simulated values and observations at Station ALOHA for physical and biogeochemical parameters. The overall levels and the amplitude of the seasonal cycles are well captured for many variables. We show that variations in net primary production are mainly driven by domain‐wide seasonal cycles of light and nitrogen fixers, respectively, as well as short‐lived, stochastic bloom events resulting from the formation of eddies to the west of the island of Hawaii. Furthermore, sporadic wind‐ and current‐driven upwelling is resulting in ephemeral enhancements of nearshore phytoplankton blooms mainly on the northeastern side of the islands.

Exchange of water and contaminants between the Strait of Istanbul and the Golden Horn

The Golden Horn (Estuary) is a hotspot for marine pollution because of its close proximity to the Strait of Istanbul (Strait) with dense maritime traffic and high pollution risk of oil spill. Transport and fate of water and contaminants in Strait and Estuary are analyzed by three-dimensional numerical models. Eddies forming at the Golden Horn junction (Junction), either on a single layer or distributed over the entire water column, block the water exchange partly or entirely across the Junction. In case of an oil spill in adjacent waters, the size and distribution of eddies at Junction control the transport and fate of contaminants inside Estuary. Using twenty test cases, the exchange flows at Junction are classified in four types based on sea level difference between north and south boundaries of Strait and Reynolds number of surface flow. Eddies may prevent the natural water exchange between Strait and Estuary but also block the contaminants penetrating to Estuary. Under predominant conditions of mild and moderate southward net flow in Strait, surface waters enter Estuary. During very strong southward flow, Junction is blocked to Black Sea water and surface contaminants. Strait hydrodynamics control water exchange with Estuary through eddy formation. When horizontal eddies are formed at Junction, their size and distribution control the transport and fate of contaminants in branching inlets and estuaries by blocking the water exchange either entirely or partly in specific layers.

Large Mesoscale Eddies in the Western Arctic Ocean From Satellite Altimetry Measurements

AbstractEddies in the Western Arctic play an important role in transporting heat, salt, and biogeochemical tracers across the continental shelf and within the deep basins. However, comprehensive observations of the regional and temporal variability of the eddy field characteristics are difficult to obtain remotely due to the presence of sea ice, and the available in situ observations remain relatively sparse. Nonetheless, with continuing global warming, increasingly large areas of the Arctic Ocean become seasonally ice‐free and can be observed with remote sensing. Here, we use satellite altimetry data acquired between 1993 and 2018 over the seasonally ice‐free Western Arctic Ocean to detect the signatures and hot spots of large mesoscale eddies, validating their detection method using independent optical and infrared satellite observations. The altimetry measurements were most frequent from July to October, revealing signatures of over 2000 individual eddies that were roughly equally partitioned between cyclones and anticyclones, with radii between 20 and 60 km and characteristic orbital velocities of about 0.05–0.4 m/s. A maximum number of eddies were detected in October in the Beaufort Sea and in November in the Chukchi Sea. The interannual variability of eddies in the Beaufort Sea is correlated with variations of intensity and freshwater content in the Beaufort Gyre. Using the regional eddy statistics, we discuss the potential eddy formation mechanisms over the key regions of their observations in the Amundsen Gulf, the area adjacent to the Mackenzie River mouth, the western part of the Beaufort Sea, and the Chukchi Sea.

Characteristics of topographic submesoscale eddies off the Crimea coast from high-resolution satellite optical measurements

Long-term arrays of satellite optical measurements of Landsat-5,7,8 and Sentinel-2 were used to describe the characteristics of submesoscale eddy (SE) dynamics in different parts of the Crimean coast: their geometric and kinematic characteristics, the main sites and mechanisms of formation, and impact on the redistribution of suspended matter. The dynamic characteristics of SE were computed on the base of the 4D variational assimilation method from the pair of consecutive Landsat-8/Sentinel-2 images. The orbital velocity of submesoscale cyclonic eddies (SCE) with a diameter of 1 km reaches 0.15 m/s, indicating the cyclostrophic balance with a high Rossby number (RO) exceeding 2. Submesoscale cyclones were detected much more frequently than the usually larger submesoscale anticyclones. High-resolution satellite imagery gives a possibility to observe complex submesoscale dynamic processes, such as the generation of chains of SCE, large cyclones behind the capes consisting of densely packed arrays of SCEs, topographic submesoscale anticyclones with a number of attached SCEs, mushroom-like current structures, and frontal SE. Despite the diversity of the processes considered, several basic mechanisms of formation of submesoscale eddies can be identified on the basis of satellite data: (1) Separation of the boundary current, often wind-driven, behind the capes; (2) barotropic instability due to the horizontal shear on the coastal periphery of mesoscale anticyclones or alongshore currents; (3) formation of the mushroom-like structure due to the interaction of offshore currents with deep waters near the capes or due to offshore winds; and (4) frontal instabilities on the coastal upwelling. The results of the analysis were used to create a scheme of the spatial variability of submesoscale processes near the Crimean coast and compare it to the results of the high-resolution modeling. The model was able to describe the main areas of SE formation, which was located near the major capes. It provides additional data about SE generation near the rocky capes of the South Crimea, where satellite data was limited by the absence of optical tracers.

Eddy formation in the bays of Kamchatka and fluxes to the open ocean

The Eastern Kamchatka Current (EKC) is the western boundary current of the North Pacific subpolar gyre. Southeast of the Kamchatka Peninsula lies a large anticyclonic eddy, the Kamchatka Eddy (KE). This eddy is quasi-stationary. More generally, the oceanic region east of the EKC contains many eddies, several of them large and long lasting. Using surface currents derived from altimetry, particle tracking and a simple two-dimensional numerical model of fluid flow, we investigate the variability of this eddy field, the generation of eddies in the bays of Kamchatka by the EKC and fluxes of water to and from these bays. Firstly, we recover in our analysis of long-lasting eddies, the main eddies of the region. Among strong eddies, the parity bias favors anticyclones. Our numerical simulations give a possible explanation for the process of eddy creation in the bays of the peninsula and show that the northernmost bay produces most anticyclones. Then, we track forward the water particles from these bays and we determine their fate in the open ocean; southeastward and southwestward trajectories are the most frequent. We also track water particles backward from the KE site; they often drift near the Kamchatka coast, but others drift south of this site and remain there, a priori trapped in other eddies. This study confirms the complexity of mesoscale motions and water exchanges in this region.

Broadband Submesoscale Vorticity Generated by Flow around an Island

AbstractAn array of moorings deployed off the coast of Palau is used to characterize submesoscale vorticity generated by broadband upper-ocean flows around the island. Palau is a steep-sided archipelago lying in the path of strong zonal geostrophic currents, but tides and inertial oscillations are energetic as well. Vorticity is correspondingly broadband, with both mean and variance O(f) in a surface and subsurface layer (where f is the local Coriolis frequency). However, while subinertial vorticity is linearly related to the incident subinertial current, the relationship between superinertial velocity and superinertial vorticity is weak. Instead, there is a strong nonlinear relationship between subinertial velocity and superinertial vorticity. A key observation of this study is that during periods of strong westward flow, vorticity in the tidal bands increases by an order of magnitude. Empirical orthogonal functions (EOFs) of velocity show this nonstationary, superinertial vorticity variance is due to eddy motion at the scale of the array. Comparison of kinetic energy and vorticity time series suggest that lateral shear against the island varies with the subinertial flow, while tidal currents lead to flow reversals inshore of the recirculating wake and possibly eddy shedding. This is a departure from the idealized analog typically drawn on in island wake studies: a cylinder in a steady flow. In that case, eddy formation occurs at a frequency dependent on the scale of the obstacle and strength of the flow alone. The observed tidal formation frequency likely modulates the strength of submesoscale wake eddies and thus their dynamic relationship to the mesoscale wake downstream of Palau.

Numerical Investigation of the Effect of Blower Baffles on the Performance of Membrane Tubes for Water Treatment

Effects of blower shaped baffles on the fluid dynamics and filtration flux in a membrane tube are numerically explored. Both the staggered and inline arrangements of baffles are studied. The carbonate calcium suspensions with a concentration of 5 g/L were used as a working medium. The efficiency of filtration was determined via the calculation of velocity of fluid particles, wall shear stresses and static pressure. An increase in the shear stresses on the tube surface, as well as a formation of fluid eddies were observed with the presence an array of blower baffles, resulting thus in a significant improvement of the filtration performance. The case of the staggered baffles with pith ratio of L/D = 1 and Re = 15,000 achieved an increase in the filtration flux rate by 42% and 12%, compared with unbaffled and tube with baffle orientation angle of 180°, respectively.

Numerical investigation of multistability in the unstable flow of a polymer solution through porous media

The accumulation of stresses as polymeric chains cross successive pores creates streaks of high polymeric stress. Highly stretched polymeric chains in the regions of high polymeric stress resist the flow crossing these streaks, leading to eddy formation in the different regions of the pores. Multiple distinct unstable flow structures occur inside the pore above a critical Weissenberg number.

Stability analysis of viscoelastic film flows over an inclined substrate with rectangular trenches

Abstract

Контроль системы течений и полей концентрации общего взвешенного и растворенного органического веществ в озере Донузлав в мае 2019 года

Based on the results of the expedition carried out in May 2019 by the A. O. Kovalevsky Institute of Biology of the Southern Seas of RAS, data on the local system of currents and the structure of the content of the total suspended matter and dissolved organic matter fields in the waters of Donuzlav Lake are obtained. It is shown that the local system of currents in the upper layer of the lake waters is represented by two cyclonic eddy formations. At the bottom along the navigable canal, a pronounced current stream directed into the sea is noted. In the structure of the total suspended matter and dissolved organic matter fields, three anthropogenic maximums of concentration coinciding in location are found, which are located at the site of sand mining, in the area of the port and in the Shchelkunov Bay, where there is a household waste collector. In the structure of the field concentration of total suspended matter and dissolved organic matter, three sites of anthropogenic concentration maxima coinciding at the location are found. They are located on the sand mining site, in the port area and in the Shchelkunov Bay, where the household waste collector operates. Sand mining, port and household waste collector are the main sources of water pollution in Lake Donuzlav. In the area of the mussel-oyster farm, an increased concentration of dissolved organic matter is identified, as a likely consequence of the vital activity of mollusks concentrated here.

Numerical Insight into the Kelvin-Helmholtz Instability Appearance in Cavitating Flow

Recently the development of Kelvin-Helmholtz instability in cavitating flow in Venturi microchannels was discovered. Its importance is not negligible, as it destabilizes the shear layer and promotes instabilities and turbulent eddies formation in the vapor region, having low density and momentum. In the present paper, we give a very brief summary of the experimental findings and in the following, we use a computational fluid dynamics (CFD) study to peek deeper into the onset of the Kelvin-Helmholtz instability and its effect on the dynamics of the cavitation cloud shedding. Finally, it is shown that Kelvin-Helmholtz instability is beside the re-entrant jet and the condensation shock wave the third mechanism of cavitation cloud shedding in Venturi microchannels. The shedding process is quasi-periodic.

Generation of Vertical Fine Structure by the Internal Waves with the Regard for Turbulent Viscosity and Diffusion

Purpose. The study is aimed at evaluating effectiveness of the procedure of the observational data assimilation using the Kalman filter algorithm as compared to sequential analysis of the hydrophysical fields based on the optimal interpolation method, and at analyzing the mesoscale features of coastal circulation near the western Crimea coast and in the Sevastopol region. Methods and Results. Based on the hydrodynamic model adapted to the Black Sea coastal zone conditions including the open boundary and on the temperature and salinity data from the hydrological survey in 2007, the dynamic and energy characteristics of the Black Sea coastal circulation were calculated with high spatial resolution (horizontal grid is ~ 1.6 × 1.6 km and 30 vertical horizons). The hydrophysical fields were reconstructed using two algorithms of data assimilation: the sequential optimal interpolation and the modified Kalman filter. The kinetic energy changed mainly due to the wind action, vertical friction and the work of pressure forces; the potential energy – due to the potential energy advection and the horizontal turbulent diffusion. The following circulation features were reconstructed: the anticyclonic eddy with the radius about 15 km in the Kalamita Bay in the water upper layer, the anticyclonic eddy with the radius about 15 km between 32.2 and 32.6° E in the whole water layer, the intense current near Sevastopol and along the Crimea western coast directed to the north and northwest, and the submesoscale eddies of different signs of rotation in the upper layer. Conclusions. It is shown that having been taken into account, heterogeneity and non-isotropy of the error estimates of the temperature and salinity fields relative to the correlation function lead to qualitative and quantitative differences in the hydrodynamic fields (amplification of currents, change of the currents’ direction and eddy formations were better pronounced). At the same time, the mean square errors of the thermohaline fields’ estimates decreased. Formation of the anticyclonic eddy with the radius about 15 km in the Kalamita Bay could be related to the current shear instability. Submesoscale eddies with the diameters less than 5 km were formed when the current flowed around the coastline and the bottom topography inhomogeneities.

Biological and Physical Interactions at Local Ocean Scales: Coupled Systems

Physical and biogeochemical processes that influence primary production set Earth’s carbon and heat budgets. While these processes have long been the focus of research, high resolution models to investigate local phenomena have only recently been developed, and two-way coupling between oceanic physics and biology is only recently getting attention due to computational power. With these new developments, it is possible to study the mechanisms through which these processes interact at both global and regional scales to shape Earth’s climate, which is the goal of this paper. This paper introduces oceanic physical phenomena at submesoscales to global scales –like mixed layer depth and turbulent structures–and the relationship of smaller scale events with biological factors. It discusses the implications of these relationships for primary production. After an introductory explanation of turbulence, primarily in the form of eddies and fronts, and the effects of internal instability and surface forcing, this paper emphasizes the contributions of those phenomena (turbulence, internal instability, and surface forcing)to vertical velocities and the influence of vertical transport on biology. Next, it introduces biogeochemical feedbacks, concerning both large scale population dynamics and increased absorption of radiation at the submesoscale, to consider their impacts on physical dynamics and regional climates. Finally, the paper compiles equations of irradiance and variables of significance, suggesting terms that could produce meaningful responses to variations in phytoplankton populations. The paper highlights the importance of understanding physical-biogeochemical relationships and suggests directions for future research, particularly areas related to global warming or abrupt climate change.

Thermo-magneto-convection and mechanism of multiple eddy formation due to applied magnetic field in a lid-driven cavity

Magnetohydrodynamic study of eddy formation and heat transfer in a bottom heated two-dimensional lid-driven cavity with the insulated sidewall is reported in this paper. We consider the classic problem of a two-dimensional lid driven cavity in the presence of an applied external magnetic field. In the standard nonlinear Navier–Stokes equation and the energy equation, appropriate terms are added to model the applied magnetic field and thermo-magnetic convection. And we have derived a higher-order numerical scheme that can provide solutions that are fourth-order accurate. The scheme is implemented with suitable fourth-order accurate boundary conditions. The square LDC enclosure is filled with a fluid of Pr = 6.2. The top lid of the cavity is kept moving with constant velocity. The effect of magnetic field on heat transfer and eddy formation is discussed for 0 ≤ Ha ≤ 250, and 103 ≤ Gr ≤ 104 and the results are presented in terms of contour plots of streamlines, isotherms, Lorentz force, and the kinetic energy. The physical mechanism for forming multiple recirculation zones is understood and attributed to two opposite forces acting in the fluid about the center-line of the cavity, which acts like a couple (and hence rotational flow). This is discovered by computing the Lorentz force acting in the entire domain of fluid flow. Similarly, from the computation of kinetic energy of the fluid at all the grid points in the fluid region, it is revealed that conduction is the dominant heat transfer mechanism at higher magnetic fields. At the same time, convection is the prime mode at low magnetic fields. It is ascertained that with an increase in magnetic field intensity, velocity profiles are suppressed, and heat transfer stabilizes, giving rise to the formation of recirculation zones in the cavity.

Analiz dinamicheskikh i energeticheskikh kharakteristik tsirkulyatsii vod u beregov Zapadnogo Kryma na osnove assimilyatsii dannykh nablyudeniy v chislennoy modeli dinamiki Chernogo morya

Purpose. The study is aimed at evaluating effectiveness of the procedure of the observational data assimilation using the Kalman filter algorithm as compared to sequential analysis of the hydrophysical fields based on the optimal interpolation method, and at analyzing the mesoscale features of coastal circulation near the western Crimea coast and in the Sevastopol region. Methods and Results. Based on the hydrodynamic model adapted to the Black Sea coastal zone conditions including the open boundary and on the temperature and salinity data from the hydrological survey in 2007, the dynamic and energy characteristics of the Black Sea coastal circulation were calculated with high spatial resolution (horizontal grid is ~1.6×1.6 km and 30 vertical horizons). The hydrophysical fields were reconstructed using two algorithms of data assimilation: the sequential optimal interpolation and the modified Kalman filter. The kinetic energy changed mainly due to the wind action, vertical friction and the work of pressure forces; the potential energy – due to the potential energy advection and the horizontal turbulent diffusion. The following circulation features were reconstructed: the anticyclonic eddy with the radius about 15 km in the Kalamitsky Bay in the water upper layer, the anticyclonic eddy with the radius about 15 km between 32.2 and 32.6° E in the whole water layer, the intense current near Sevastopol and along the Crimea western coast directed to the north and northwest, and the submesoscale eddies of different signs of rotation in the upper layer. Conclusions. It is shown that having been taken into account, heterogeneity and non-isotropy of the error estimates of the temperature and salinity fields relative to the correlation function lead to qualitative and quantitative differences in the hydrodynamic fields (amplification of currents, change of the currents’ direction and eddy formations were better pronounced). At the same time, the mean square errors of the thermohaline fields’ estimates decreased. Formation of the anticyclonic eddy with the radius about 15 km in the Kalamitsky Bay could be related to the current shear instability. Submesoscale eddies with the diameters less than 5 km were formed when the current flowed around the coastline and the bottom topography inhomogeneities

Fatigue Analysis for Fe-34.5Mn-l0Al-0.76C Tidal Turbine Blades using Rainflow Algorithm

This study investigates the effect of the environmental conditions (seawater mean thrust force and flow velocity) on a tidal turbine for different thicknesses mathematically. This had been achieved through predicting the fatigue stresses applied on the turbine for different conditions using Rainflow algorithm. The blades of the tidal turbine should be characterized by a low roughness to reduce eddies formation downstream the seawater flow. Fe-34.5Mn-l0Al-0.76C alloy had been selected in this study. Obtained results showed that, increasing thickness of the blade resulted in increasing the turbine lifespan for each studied flow velocity and thrust forces. However, increasing the flow velocity is predicted to increase the thrust forces due to the wake region formed downstream the flow leading to increase the fatigue stress on the blade. Consequently, the blade thickness should be optimized based on the geographical location decided to be installed by a turbine. As the geographical location effects on the environmental conditions significantly, which should be considered during the design stage to prevent fatigue failure of the turbine. Optimizing the blade thickness would help in maximizing the energy conversion efficiency of the turbine as well, as a lightweight blade would be able of generating electricity higher than heavy ones.

Filaments, Fronts and Eddies in the Cabo Frio Coastal Upwelling System, Brazil

We investigate the dynamics of meso- and submesoscale features of the northern South Brazil Bight shelf region with a 500-m horizontal resolution regional model. We focus on the Cabo Frio upwelling center, where nutrient-rich, coastal waters are transported into the mid- and outer shelf, because of its importance for local and remote productivity. The Cabo Frio upwelling center undergoes an upwelling phase, from late September to March, and a relaxation phase, from April to early September. During the upwelling phase, an intense front around 200 km long and 20 km wide with horizontal temperature gradients as large as 8 ∘C over less than 10 km develops. A surface-intensified frontal jet of 0.7 ms−1 in the upper 20 m and velocities of around 0.3 ms−1 reaching down to 65 m depth makes this front a preferential cross-shelf transport pathway. Large vertical mixing and vertical velocities are observed within the frontal region. The front is associated with strong cyclonic vorticity and strong variance in relative vorticity, frequently with O(1) Rossby numbers. The dynamical balance within the front is between the pressure gradient, Coriolis and vertical mixing terms, which are induced both by the winds, during the upwelling season, and by the geostrophic frontal jet. Therefore, the frontal dynamics may be largely described as sum of Ekman and turbulent thermal wind balances. During the upwelling phase, a mix of barotropic and baroclinic instabilities dominates in the upwelling center. However, these instabilities do not lead to the local formation of coherent eddies when the front is strong. In the relaxation phase, the front vanishes, and the water column becomes less stratified. The interaction between eastward coastal currents generated by sea level variability, coastal intrusions of the Brazil Current, and sporadic wind-driven, coastal upwelling events induce the formation of cyclonic eddies with diameters of, approximately, 20 km. They are in gradient-wind balance and propagate along the 100-m isobath on the shelf. During this phase baroclinic instability dominates. Cold filaments with widths of 2 km are formed due to straining and stretching of cold, coastal temperature anomalies. They last for a few days and are characterized by downwelling as large as 1 cms−1. The turbulent thermal wind balance provides a good first order estimate of the dynamical balance within the filament, but vertical and horizontal advection are shown to be important. To our knowledge, this is the first account of these smaller scale features in the region. Because these meso- and submesoscale features on the shelf heavily affect the water properties crucial to productivity of the South Brazil Bight, it is important to take these features into account for a better understanding of the functioning of this ecosystem and its resilience to both direct human activities as well as to climate change.