Ekman flow upwelling. The prevailing trade winds converge toward the equator.

Ekman flow upwelling. 36 Ekman pumping If there is convergence or divergence of Ekman transport, then there will be upwelling or downwelling at the base of the Ekman layer. Any spatial variability of the wind, or winds blowing along some coasts, can lead to upwelling. 8. See also: windstress and cdtcurl. The Coriolis Effect causes the surface water to move in a direction about 45 degrees offset from the wind direction, with the deflection to the right of the wind in The Ekman spiral and Ekman transport are named for Swedish scientist V. The results show that the equatorial zonal wind stress directly drives the meridional motion of seawater at the upper levels. Convergence and divergence of Ekman flow This horizontal flow causes vertical flow (upwelling and downwelling), which generate pressure gradients to great depths (1000 m) The small Ekman compensation flow, which drives the upwelling, moves nutrients into the euphotic zone. Feb 1, 1999 · Cross-boundary wind variations, or equivalently wind stress curl, drive Ekman divergences and provide an additional source of upwelling as well as downwind flows and countercurrents. This drives a westward geostrophic flow at the sea surface, much like the eastern boundary current Study with Quizlet and memorize flashcards containing terms like Sir John Murray observed that the temperature of the ocean's surface water was almost always higher than the temperature of deep water. This drives a geostrophic westward flow, much like the eastern boundary current flow. Get a complete understanding of these important oceanographic concepts at Mappingaround. The Coriolis effect causes surface waters to move at an angle relative to the wind direction Nov 15, 2018 · Abstract Ekman transport is a key factor in the coastal upwelling regimes in the northern coastal region of the Persian Gulf. This offshore transport is compensated by onshore flow at depth and upwelling. Let’s quantify the consequences of these boundary layer flows in two examples in coastal upwelling. and more. Coastal Upwelling and Downwelling The continental margins of the world are places where coastal upwelling and downwelling are taking place (Figure 9. Ekman transport contributes to fundamental features of the surface ocean. This problem is revisited Mar 30, 2023 · Upwellings Upwelling refers to an oceanographic phenomenon that includes the wind-driven movement of cool, nutrient-rich, dense waters from deeper ocean depths toward the ocean surface to replace the warm, nutrient-depleted surface water. à Ekman upwelling/downwelling can drive the horizontal geostrophic circulation. (2018) defined a new upwelling index for the California Current System, the Coastal Upwelling Transport Index (CUTI), which formally accounts for the geostrophic flow competing with the offshore Ekman transport. In Figure 8A-2, the coastal downwelling occurs offshore of the ______ while coastal upwelling would be happening offshore of the opposite coast: Western coast. Ekman transport causes the near-surface flow under a northerly wind in the Northern Hemisphere. 3). Wind-driven Currents and Ekman Transport The wind blows across the ocean and moves its waters as a result of its 9. - Warm water from near Australia migrates toward South America. According to the concept proposed by the 20th-century Swedish oceanographer V. Warm water originating near Australia migrates toward South America. Study with Quizlet and memorize flashcards containing terms like If there are no continents what would surface currents do?, What do the surface currents do to the high latitudes?, What happens to the water at the center of a gyre? and more. Study with Quizlet and memorize flashcards containing terms like Regarding the affects of Coriolis on ocean circulation: What is meant by "Geostrophic Flow?", What is meant by "Ekman Spiral" and "Ekman Transport?", Know the process behind coastal upwelling and downwelling. ” Gravity causes the water to flow back “downhill. The reverse process, called downwelling, also occurs when wind causes surface water to build up along a coastline. Here the authors show that geostrophic flow Ekman pumping refers to the vertical movement of water in the ocean caused by the non-zero curl of the wind stress, resulting in downwelling when the wind has a negative curl and upwelling for a counterclockwise rotation. Again, imagine yourself in a boat at the tail of the wind arrow looking in the direction the wind is blowing. The Ekman layer is the layer in a fluid where the flow is the result of a balance between pressure gradient, Coriolis The movement of surface currents also plays a role in the vertical movements of deeper water, mixing the upper water column. Cross-shore Ekman flow profiles from the analytical model with null cross-shore geostrophic flow (left) and 1 cm/s onshore geostrophic flow (right). The associated lowering of the sea surface May 11, 2010 · [1] The convergence as resolution is increased is examined for a numerical model simulation of upwelling over a continental shelf canyon. Ekman transport primarily disrupts nutrient flow in the ocean, leading to a Ekman transport is the net motion of fluid as the result of a balance between Coriolis and turbulent drag forces. Ekman transport moves the surface layer 90 o to the right of the wind, meaning the net Ekman transport is in an offshore direction. The proposed Geostrophic and Ekman Current Observatory (GEKCO) is described methodologically, along with the different data sets required. It plays a minor role in marine ecosystems and does not significantly affect climate regulation or fishing grounds. Jan 1, 2015 · Abstract Model analyses of an alongshelf flow over a continental shelf and slope reveal upwelling near the shelf break. In the picture above, the wind blowing North in the northern hemisphere creates a surface stress and a resulting Ekman spiral is found below it in the water column. This process, with conservation of angular momentum on the rotating Earth, induces the water column to Learn about the ocean in motion and how ocean surface currents play a role in navigation, global pollution, and Earth's climate. In the atmo-sphere, the wind direction makes a larger but widely varying angle with the isobars on land than offshore and points more Nov 1, 2020 · Here, sea level anomaly (SLA), Ekman transport, Ekman pumping velocity and Brunt–Vaisala frequency are considered as indices as well as proxies for upwelling. Vigorous upwelling zones are Upwelling occurs in the open ocean and along coastlines. Overview Ocean flow field can be described as additive combination of the following 2 components: Ekman Transport – part of the flow that responds to wind-stress forces exerted at sea surface Upwelling Learning Goals 10e: Describe the processes that drive coastal upwelling, and explain how upwelling and sea surface temperatures create fog. Mar 9, 2016 · This may mean that upwelling of nutrient-rich water occurs within the eddy, but such upwelling is not captured by models that resolve mesoscale processes. The Ekman layers and patterns of upwelling and downwelling can be visualized by using dye crystals and paper dots. The Swedish scientist Walfrid Ekman described the details of this process in The Ekman layer is defined as the surface boundary layer in the ocean where the frictional force is balanced by the Coriolis force, facilitating the transformation of wind stress downward through eddy-induced horizontal momentum flux. In this study, a cross shore extension of the classical 1905 Ekman’s solution is derived and this new two dimensional solution clarifies the basic mechanism of upwelling separation from the coast : Upwelling occurs offshore from a “kinematic barrier” to the cross shelf flow, which results from the complete merging of the upper and lower Aug 29, 2023 · The classical Ekman theoretical solution for steady-state wind-driven currents of homogeneous ocean with constant eddy viscosity was obtained more than a century ago. , Which of the following statements is true about an Ekman spiral? and more. In order to take into account the effect of the topography Sep 1, 2013 · The advection time, defined as the time scale for cold water to be advected from the pycnocline to the ocean surface, is improved to comprise of climbing time and upwelling time. The poleward Ekman transport results in upwelling on the equator. The intensity of the prevailing westerlies increases as they flow over South America. Dec 1, 2021 · This study aims to describe characteristics of seasonal Ekman upwelling by analyzing oceanographic parameters from the validated INDESO model output (2008-2014). , Describe the relationship between trade winds and biological SUMMARY: The historical file of wind observations from maritime weather reports is summarized to identify the charac-teristic seasonal distributions of wind-induced Ekman upwelling and downwelling in the Mediterranean Sea. Over the slope Geostrophic flow is the balance between Coriolis effects causing currents to form a bulge of water in the center of ocean gyres and gravity currents also affected by the Coriolis effect. What is the Coriolis Effect, Ekman Spiral, and Upwelling? What do they have to do with each other? Here is a quick video explaining the concept of each term Nov 29, 2021 · Here, we focus on the upwelling driven by offshore Ekman transport and present a scaling relation for the source depth and density by considering a balance between the wind-driven upwelling and eddy-driven restratification processes. In this paper, the Ocean Module of Parallelized Large-Eddy Simulation Model (PALM) was utilized so as to investigate the Ekman layer and estimate the water mass transport in the Persian Gulf for the first time. Conventional patterns of vertical velocity, Ekman pumping, appear in the upper ocean, with topographic dominance at depth. Here we study the mechanism by which the wind drives ocean circulation. Upwelling is the process that brings deeper water to the surface, and its major significance is that it brings nutrient-rich deep water to the nutrient-deprived surface, stimulating primary production (see section 7. counter-current circulation c. e. Which of the following statements about El Niño events is false? Figure 8. Dec 1, 2024 · Upwelling is a phenomenon that occurs due to forcing from wind forces aligning with the coastline, resulting in windstress that generates Ekman currents. Flow field related to upwelling is directed at an angle away from the coast near the surface, parallel to the coast at mid-depth (below the Ekman layer but above the bottom boundary layer) and at an angle towards the coast in the frictional boundary layer at the bottom. Jan 1, 1983 · In the early phase of the monsoon response, during May, with weak southerly winds off Somalia, a cross equatorial inertial current develops which turns offshore a few degrees north of the equator with a coastal upwelling wedge just north of the offshore flow. [9] Returning to the concept of mass conservation, any water displaced by Ekman transport must be replenished. We introduced the concept of upwelling back in section ‘9c Walker Cell and ENSO’, but here, we will look at it in closer detail and explore the relationship between upwelling and sea fog. , Surface currents flow vertically in the uppermost 400 meters of the water column. Using these results as a guide, a bottom Ekman layer-resolving three-dimensional numerical model Wind blowing across the surface of the ocean transfers energy to the water through friction, creating surface currents. In particular, if given a wind direction along a coast, know how the surface ocean currents will flow. Along oceanic eastern boundaries, equatorward wind stress and the Earth's rotation combine to drive a near-surface layer of water offshore, a process called Ekman transport The divergence of the Ekman flow causes upwelling on the equator. The upwelling Mar 22, 2023 · A current along a sloping bottom gives rise to upwelling, or downwelling Ekman transport within the stratified bottom boundary layer (BBL), also known as the bottom Ekman layer. 3 The Ekman Spiral and Geostrophic Flow Paul Webb Ekman spiral Winds blowing over the ocean are ultimately what create the surface currents. [1] Ekman suction Ekman suction is the component of Ekman transport that results in areas of upwelling due to the divergence of water. Oct 1, 2021 · The Ekman spiral occurs in the ocean as well as the atmosphere . This produces a surface Ekman layer transport directed 90º to the right (left) of the wind direction; in both hemispheres, this results in offshore surface water movement. Aug 1, 2021 · Based on these results, Jacox et al. 3 Coastal upwelling. Intense and vertically coherent upwelling and downwelling occur in the Southern Mar 13, 2025 · A. Learn how wind blowing across the ocean surface affects the movement of water, the creation of ocean gyres, and the distribution of heat and properties around the world. Recall from Chap. The main drivers that work together to cause upwelling are wind, current flow, Coriolis effect, and Ekman transport. Walfrid Ekman (1874-1954, a Swedish physicist Spatial variability in wind current leads to upwelling near the shore. In normal years, the zonal wind stress south of the equator is easterly and that north of the equator is westerly, which Jul 25, 2013 · Relative roles of Ekman transport and Ekman pumping in driving summer upwelling in the South China Sea (SCS) are examined using QuikSCAT scatterometer wind data. The vigorous along-shore, near-surface currents and oppositely directed undercurrents are important for the ecosystem response because they can move cells and copepods alongshore. - Thermohaline flow becomes unusually strong. Because of Ekman transport, an anticyclonic circulation causes a convergence of surface waters and a cyclonic circulation a divergence. When wind blows parallel to a long coastline for a considerable period of time (for a steady state to develop), a Purpose of Activity Here we study the mechanism by which the wind drives ocean circulation. The upwelling Ekman spiral, theoretical displacement of current direction by the Coriolis effect, given a steady wind blowing over an ocean of infinite depth, extent, and uniform eddy viscosity. C) Warm water originating near Australia migrates toward South America. In the offshore, wind stress curl leads to the formation of meso-scale eddies, resulting in Ekman pumping at the center and consequent upwelling. Mr. W. Figure \ (\PageIndex {2}\) Geostrophic flow in the Northern Hemisphere. eastward 6. in. Mass conservation, in reference to Ekman transfer, requires that any water displaced within an area must be replenished. This research focuses on the offshore transport of the buoyant water through Ekman dynamics under upwelling-favorable conditions. Western intensification is ________. We will induce cyclonic and anticyclonic circulation by blowing air over the surface of a rotating tank of water using fans co-rotating with the turntable, as sketched in Fig. Conversely, a divergent Ekman transport will produce an upwelling flow from the interior into the surface layer (see Figure 8). 18). Wind-driven Currents and Ekman Transport The wind blows across the ocean and moves its waters as a result of its Once the wind sets surface waters in motion as a current, the Coriolis effect, Ekman transport, and the configuration of the ocean basin modify the speed and direction of the current. 0 (–4. From: Design Principles of Ships and Marine Structures [2019], Spatio-temporal variations in upwelling indices in Arabian Sea coastal upwelling systems and associated biological productivity using remote sensing observations [2023] Study with Quizlet and memorize flashcards containing terms like Of the following locations, where would upwelling be expected to occur? Choose all that apply. But momentum from the wind field is transferred into the ocean by friction; so frictional forces must be important in the surface boundary layer. The vertical velocity at the base of the Ekman layer is often referred to as Ekman pumping. 38. As a result of the wind, the water has The easterly trade winds cause northward Ekman transport just to the north of the equator and southward Ekman transport just to the south of the equator. geostrophic circulation e. Because steady winds blowing on the sea surface produce an Ekman layer that transports water at right angles to the wind direction, any spatial variability of the wind, or winds blowing along some coasts, can lead to upwelling. - Ekman transport can result in both upwelling and downwelling. In the open ocean, it leads to both upwelling and downwelling, which redistribute the mass of water in the ocean. Edwards3, Elliott L. Where winds blow toward shore or Ekman flow carries surface water toward shore. Replace the geostrophic flow pressure gradients: The continuity equation becomes: Ekman pumping (ѡ E) is related to the convergence of the Ekman transport: Therefore, we obtain: geostrophic Sverdrup - (Ekman transport transport Transport) Therefore, Learning objectives - understand forcing & processes for Ekman currents Surface Ekman layer & forces of balance (continue) Wind-driven Ekman spiral, Ekman transport and coastal & equatorial upwelling Open Ocean Ekman pumping Bottom boundary layer Jan 1, 2015 · The latitudinal variation in the westerlies creates a divergence in the Ekman transport, which causes water to upwell along the sloping density layers from the deep ocean to the surface. This happens when winds cause Ekman transport to push water toward a coast and then deeper in the ocean. The major upwelling regions in the SCS are the coastal regions east and southeast of Vietnam (UESEV), east and southeast of Hainan Island (UESEH), and southeast of Guangdong province (USEG). Question: Question: Winds blowing at the sea surface result in Ekman transport, moving near-surface water (~100 m) either to the right in the northern hemisphere) or to the left (in the southern hemisphere) of the direction of the wind. Coastal Upwelling and Weather Abstract The Ekman spiral exists in the near-surface ocean just as in the near- surface atmosphere. Choose all that apply. The first arises from the surface stress that occurs because of differences between surface wind and ocean velocities, resulting in Ekman upwelling and downwelling in the cores of anticyclones and cyclones, respectively. - Ekman transport can result in both upwelling and Oceanographers have long sought to verify the theoretical Ekman transport relation, which predicts that a steady wind stress acting together with the Coriolis force will produce a transport of water to the right of the wind. 22. The dynamics of this layer are best understood if it Ekman transport driven upwelling and downwelling also occurs in the open ocean Just like along the coast, upwelling along the equator brings nutrient-rich water to the surface stimulating primary productivity. 6. , Why do ocean currents not move in the same direction as the wind? and more. 2 Ageostrophic flow at the surface induced by the action of the wind: anticyclone of left, cyclone on right. In this study, the Ekman analytical solution is compared with currents obtained by These Ekman flows can converge and produce a downwelling flow into the interior of the ocean. The Ekman transport and pumping largely explain the wind-driven circulation in the upper ocean, including the gyre circulation and upwelling/downwelling systems. However, not all of the water moved by the surface currents is transported in the same direction. - In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction. 3. High-resolution simulations presented here show intense submesoscale upwelling from the thermocline to the mixed layer in anticyclonic eddies. The associated lowering of the sea surface Choose all that apply. They operate differently for different types of upwelling, but the general effects are the same. Over the depth of the spiral, the average flow of the water set in motion by the wind, or the net flow, moves 90° to the right (Northern Hemisphere) or left (Southern Hemisphere) of the surface wind. Upwelling occurs in the open ocean and along coastlines. The dynamics of this layer are best understood if it Hydroform Type: Upwardly-directed current resulting from either the divergence of water masses or from movement of surface water away from the coast. Ekman transport- the total volume of water in the Ekman layer transported at right angles to the wind direction. This includes coastal upwelling regimes which provide the nutrient supply for some of the largest fishing markets on the planet, as well as equatorial upwelling where Apr 20, 2006 · Spatial variability of transports in the open ocean leads to upwelling and downwelling, which leads to redistribution of mass in the ocean, which leads to wind-driven geostrophic currents via Ekman pumping. 0 license and was authored, remixed, and/or curated by Paul Webb via source content that was edited to the style and standards of the LibreTexts platform. The water displaced near the coast is replaced by cold, nutrient-rich deeper water that is brought to the surface through upwelling, leading to high productivity (Figure \ (\PageIndex {3}\)). The ekman function estimates the classical Ekman transport and upwelling/downwelling from 10 m winds. At the onset of strong winds in June, a northern Near the bottom boundary, there is inflow when ω has the same sign as Ω (cyclonic flow) and outflow when ω has the opposite sign (anticyclonic) - think about our Ekman layer experiment, GFD X. Here, the authors attempt to clarify the energy pathways Ekman transport piles up water between the trade winds and westerlies in subtropical gyres, or near the shore during coastal downwelling. the gyres) and explain how they are formed identify the features of the Gulf Stream, including the formation of warm and cold core rings explain the development and consequences of the Ekman spiral explain geostrophic flow, and how it helps keep the gyres flowing . Figure 9. The upwelling of subsurface ITF along the south Java coast is found to occur from August to October. The flow For zero heat fluxes the release of available potential energy by baroclinic instabilities is strongest and leads, near the coast, to nearly full cancellation of the Ekman cross-shore circulation by eddy effects, i. g. At the bottom, there is a flow in the boundary layer that is to the left of the interior flow. The Coriolis Effect (Ekman Transport) can affect near-shore currents as well as those in the deep ocean. The effects of the spatiotemporal upwelling mechanisms variability are then explored using current observations along with sea surface temperature Ekman pumping downward in the central ocean is a consequence of this convergence of water. coastal upwelling Why are the world's most productive fisheries located in areas of coastal upwelling? c. The Coriolis Effect causes the surface water to move in a direction about 45 degrees offset from the wind direction, with the deflection to the right of Mar 20, 2023 · 5. a. PurPosE oF ActiVity Here we study the mechanism by which the wind drives ocean circulation. In the vicinity of a coast, Ekman transport would result in coastal upwelling or downwelling depending on the wind direction relative 9. Moreover, the figure demonstrates the disappearance of elongated dense isobaths in run 2, due to the removal of wind stress force from the control run. In coastal areas where prevailing winds blow along the coast, Ekman transport causes surface water to flow offshore. Along oceanic eastern boundaries, equatorward wind stress and the Earth's rotation combine to drive a near-surface layer of water offshore, a process called Ekman transport Jan 30, 2023 · Oceanic eastern boundary currents are regions with strong upwelling, which is expected to intensify with global warming through enhanced winds. This is because it leads to upwelling (Ekman suction) and downwelling (Ekman pumping) in order to obey mass conservation laws. North of that region, an Ekman upwelling regime exists all the way up the coast. Warm water from near Australia migrates toward South America. To explain this remarkable observation, Ekman (1905) … The disturbed wind field and associated Ekman flow and upwelling process may explain the variations in the current and nutrient transports after the typhoon. , Distinguish between coastal upwelling and equatorial upwelling. Longshore win The most important episodes of coastal upwelling and downwelling, in terms of size, duration, and economic importance, occur due to longshore wind. Where winds blow away from shore or Ekman flow carries surface water away from shore. Upwelling connectsthe oppositelydirected sur- face and bottom Ekman layer flows,completing the circuit and maintaining continuity. Such flow patterns are, for example, known in marginal ice zones near ice edges (e. Nov 1, 2002 · Abstract Steady wind-driven flow along a shelf of changing width is described with a frictional barotropic model valid in the limit of small Rossby and Burger number. , Of the following gyres, which one(s) flow in a counterclockwise direction?, Of the following statements about the Ekman spiral and Ekman transport, which is/are true? Choose all that apply. Alongshore wind (coast at the left in the Northern hemisphere) produces offshore Ekman transport in the upper Ekman layer. , The primary force responsible for surface currents is ____. The molecular kinematic viscosity \ (\nu\) could be used, and that gives an exact solution for a laminar Ekman layer. The latter is related to the upwelling divergence driven by surface Ekman flow. Consequently, coastal upwelling of cold nutrient-rich water is more frequent, widespread, and persistent on the west coasts of the continents. This surface flow then modifies the flow Feb 10, 2017 · This study analyzes two wind-induced upwelling mechanisms, namely, Ekman transport and Ekman pumping that occur during the southwest monsoon. Jul 15, 2022 · Intensity of upwelling was estimated using the combined effect of Ekman transport and pumping, which itself is a direct measure of upwelling favourable wind field in the region. The piling up of water at mid-latitudes contributes to the formation of gyres that circulate in all of Earth's major ocean basins. , Fennel and Johannessen 1997). The effect is a consequence of the Coriolis effect which subjects moving objects to a force to the right of their direction of motion in the northern hemisphere (and to the left in the Oct 2, 2018 · Coastal upwelling is responsible for thriving marine ecosystems and fisheries that are disproportionately productive relative to their surface area, particularly in the world's major eastern boundary upwelling systems. 48 7. Download Full-text SUMMARY: The historical file of wind observations from maritime weather reports is summarized to identify the charac-teristic seasonal distributions of wind-induced Ekman upwelling and downwelling in the Mediterranean Sea. 0 ± 2. Aug 19, 2016 · The Ekman transport due to alongshore winds, Ekman pumping due to wind stress curl, cyclonic eddy and southward West Indian Coastal Currents play different roles in the SEAS upwelling. S. Back to Climate Data Tools Contents Contents Study with Quizlet and memorize flashcards containing terms like Describe the role played by Ekman transport in coastal upwelling. Each layer of water molecules is moved by friction from the shallower layer, and each deeper layer moves more slowly 5. The classical Ekman pumping theory and its later extensions consider the Ekman pumping induced by wind stress, whereas abundant density fronts embedded in the surface boundary layer generate geostrophic stress comparable in magnitude to wind stress. Langmuir circulation Oct 15, 2006 · Abstract The oceanic Ekman transport and pumping are among the most important parameters in studying the ocean general circulation and its variability. Upwelling In many parts of the world winds blow predominately one way along the Optimum upwelling conditions are obtained when the Ekman transport divergence is maximized, which occurs when the Ekman transport is directed offshore and normal to the coastline. Upwelling due to the Ekman transport divergence has been identified as a leading mechanism for the seasonal to interannual variability of the upper-ocean heat content in many parts of the World Ocean, especially along coasts and the equator This is due to the absence of the longshore wind stress that is required to generate offshore Ekman flow for the upwelling process to occur. 3 The Ekman Spiral and Geostrophic Flow Ekman spiral Winds blowing over the ocean are ultimately what create the surface currents. , Due to the combined effect of wind friction, Coriolis Effect, Ekman Transport, land mass, and the pressure gradient, ocean currents tend to ____. Sea surface chlorophyll-a concentration (SSC), a key indicator of marine productivity with direct implications for fisheries potential, is investigated in this study Explore the connection between the Ekman Spiral, ocean gyres, and upwelling of water. Observations comprised CTD casts and shipborne ADCP profiles as well as near surface flow measurements from a floating platform and microstructure profiles in uprising mode. Figure 19 shows that surface convergence and divergence have an effect beneath the surface. From these graphics, we can see or infer each of the following In these regions, offshore Ekman transport causes upwelling of cold nutrient-rich subpycnocline water. It is demonstrated that in the Atlantic equatorial region this upwelling is dominated by Ekman processing in the west, whereas in the east it is primarily owing to As Ekman realized, the transport in the near surface is 90o to the right of the wind (in the northern hemisphere). The prevailing trade winds converge toward the equator. This movement of water away from the coast at the surface causes deeper water to upwell. , phytoplankton) that support marine food webs and fisheries. Distinguish between coastal upwelling and equatorial upwelling. Ekman transport directed away from the coast generates _______. Here we investigate how air–sea Ekman Spiral and Ekman Transport Early sailors traveling in regions where icebergs are common noticed that the icebergs moved in a different direction than the wind (causing alarm as the icebergs were cutting across the paths of ships moving down wind). upwelling index), the ecological response to coastal upwelling events, the location of significant upwelling regions, their general Mar 28, 2017 · Data derived from satellite-based observations, with buoy-based observations and assimilations, are used to calculate ocean Ekman layer transport and evaluate long-term trends in the Arctic Ocean over the period 1979–2014. Both coastal upwelling/downwelling and wind-stress curl-driven “open ocean” upwelling/downwelling are treated in a unified descrip-tion. Feb 15, 2017 · Have you ever gone to the beach to find the water much colder than the day before? A range of factors influence sea surface temperatures in coastal waters. E) Ekman flow phenomena occur, causing the movement of surface currents. This drives a westward geostrophic flow at the sea surface, much like the eastern boundary current Nov 22, 2023 · The Ekman spiral and Ekman transport are related to the movement of ocean water caused by wind. The derivation for the atmosphere was already presented in Chap. In these limits, an alongshore wind drives enhanced onshelf transport in a coastal ocean if the shelf widens downwind, and the change in shelf width only affects the flow in the direction of Kelvin wave propagation (“downwave Which type of current flow moves in a circular path around a subtropical convergence, reflecting Ekman transport, gravity, and the Coriolis effect? a. As with the gyres, geostrophic flow is clockwise in the Northern Hemisphere, and counterclockwise in the Southern Hemisphere. Jan 1, 2021 · Coastal upwelling and downwelling refer to the upward and downward transports of water mass, respectively. May 24, 2007 · This bottom Ekman transport is of particular interest on continental shelves, such as off Oregon, because it helps drive the upwelling of deep, nutrient-rich near-bottom water during southwards geostrophic flow (see Kundu [1976], Huyer and Smith [1978], and Perlin et al. The problem is that the mean-flow Reynolds numbers of large-scale flow in both the ocean and the atmosphere are so large that the Ekman layer must be turbulent rather than laminar. Lima discusses how the surface winds and the coriolis effect combine to create current patterns that circulate nutrients and heat throughout the oceanic During a non-El Niño year, the air and surface water flow westward to the western Pacific, the thermocline rises, and upwelling of cold water occurs along the west coast of Central and South America. The Ekman layers and patterns of upwelling and downwelling can be made visible through the use of dye crystals and paper dots. To help him make a mathematical model of these movements, Ekman used the observations that Fridtjof Nansen made while frozen into the Arctic sea ice. Upwelling is the rise of cold, nutrient-rich water Ekman transport can result in both upwelling and downwelling. 1. Ekman transport influences nutrient distribution through upwelling, supporting marine ecosystems and impacting climate regulation and fisheries by enhancing biodiversity in nutrient-rich waters. This net water flow is called Ekman transport. C. In Figure 7B-2, the coastal downwelling occurs offshore of the while coastal upwelling would be happening offshore of the opposite coast. The Coriolis effect causes surface waters to move at an angle relative to the wind direction. - Ekman transport is the driving force for thermohaline flow. It is shown that the Ekman transport due to Easterly trade winds at the equator drive (1) poleward Ekman transport and (2) westward surface flow. Jul 20, 2020 · Coastal upwelling was induced by an upwelling-favourable wind in July, resulting in the dynamic uplift of deep, cold water. Downwelling is the opposite of upwelling - surface waters pushing down into deeper areas of the ocean. The water displaced near the coast is replaced by cold, nutrient-rich deeper water that is brought to the surface through upwelling, leading to high productivity (Figure 9. The dynamic uplift decreased the steric sea level in the coastal region. A series of idealized one- and two-dimensional models are used to plot the dependence of bottom Ekman layer velocity structure and transport on model resolution. Ekman layer- the surface layer of water approximately 100-150 m (330-500 ft) thick Jan 1, 2015 · Abstract Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies are investigated. Study with Quizlet and memorize flashcards containing terms like When Coriolis effect and gravity are balanced in a subtropical convergence, what is the result? geostrophic current eastern boundary current Ekman transport subtropical gyre, An Ekman spiral is a balance between what two factors? wind and friction Coriolis effect and friction surface current and wind wind and Coriolis effect Choose all that apply. Stern-Ekman pumping modifies the classical Ekman pumping by taking into consideration of ocean eddy vorticity. Walfrid Ekman who first described the spiral in 1905. Geostrophic circulation extends much deeper depths, over several hundreds of meters. 7 ± 2. Ekman transport generates vertical water motions (upwelling or downwelling) through several mechanisms. In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction. westward b. (Eddies and the flow of the strong eastward Antarctic circumpolar current over topographic ridges also influence the upwelling, as outlined in box 2. - Ekman transport is to the right of the wind direction in the Northern Hemisphere. Feb 21, 2013 · The aim of this study is to improve estimates of the wind-driven currents via standard Ekman formalism and to tackle the specific singularity of the equator. Cross-shore Ekman currents are normalized by the surface Ekman current and the streamfunction is normalized by the Ekman transport. The second mechanism arises from the interaction of the D) Upwelling increases along the coast of Peru. The Coriolis Effect causes the surface water to move in a direction about 45 degrees offset from the wind direction, with the deflection to the right of the wind Upwelling increases along the coast of Peru Warm water from near Australia migrates toward South America. Time series of (a) the upwelling index, (b) Ekman transport, (c) Ekman pumping transport, (d) the slope of the interface, and (e) the sea level differences between the coastal and offshore regions What is the relationship between wind flow, Ekman transport, and upwelling in coastal regions? In coastal regions, the Ekman transport pushes the water away from the coast and it is replaced by the cooler (nutrient-rich) water below as a result of upwelling. - Ekman transport results in converging surface currents along the equator. density-driven circulation d. 7. In the deep ocean coastal upwelling occurs where the wind blows parallel to the coast with the coastline on its left (right) in the northern (southern) hemisphere (Figure 6. Coastal upwelling occurs where Ekman transport moves surface water away from the coast. Ekman transport is to the right of the wind direction in the Northern Hemisphere. A) Ekman transport moves water into the middle of the gyre, where it “piles up. Through vertical eddy viscosity, winds act directly and frictionally on the Ekman layer, which typically is the upper 50–100m in the ocean. [6] In the overall process of upwelling, winds blow across the sea surface at a particular direction, which causes a wind-water interaction. Apr 18, 2025 · The Ekman pumping is one of the fundamental mechanisms via which the inviscid ocean interior is driven into motion. The Ekman spiral, named after Swedish scientist Vagn Walfrid Ekman (1874-1954) who first theorized it in 1902, is a consequence of the Coriolis effect. Ekman drift and coastal upwelling What is the net transport in the wind-driven Ekman layer and its consequence in the coastal region? Download scientific diagram | Scheme of the Ekman transport during a coastal upwelling favorable wind and b coastal downwelling favorable wind from publication: A coupled numerical model to Question: Discuss two differences between coastal upwelling and downwelling with respect to the Ekman flow (whether the surface seawater moves offshore or to the shore) and what happens to the biological productivity. West Coast Michael G. thermohaline circulation b. Ekman transport causes the ______ near-surface flow under a northerly wind in the Northern Hemisphere:Westward. Similar to the atmosphere , surface waves in the ocean can disrupt the predicted motion. Western coast In the Southern Hemisphere, how do you expect upwelling and downwelling to play out? Ekman transport refers to the mass flow of water caused by the combined effect of coastal upwelling and open ocean upwelling, which is due to Ekman suction. " Ekman layer transports, Ekman pumping, and the Sverdrup balance Geostrophic flow, or the flow produced by a balance between the pressure gradient force and the Coriolis force, is frictionless flow. The frictional surface flow (u) is at an angle to the right of the wind in the northern hemisphere, to the left in the southern hemisphere (45 degrees if viscosity is uniform in the vertical z -direction). Jul 14, 2025 · Ocean current - Gyres, Upwelling, Ekman Transport: Ocean circulation derives its energy at the sea surface from two sources that define two circulation types: (1) wind-driven circulation forced by wind stress on the sea surface, inducing a momentum exchange, and (2) thermohaline circulation driven by the variations in water density imposed at the sea surface by exchange of ocean heat and water Oct 2, 2018 · Coastal upwelling is responsible for thriving marine ecosystems and fisheries that are disproportionately productive relative to their surface area, particularly in the world's major eastern boundary upwelling systems. It can occur near boundaries, where an along-shore component of the wind stress creates a coastal divergence (or convergence) in the Ekman layer. In this study, we Coastal Upwelling Revisited: Ekman, Bakun, and Improved Upwelling Indices for the U. Considering both sides of the equator, the trades winds cause Ekman transport away from the equator generating upwelling. Coastal upwelling circulation We found that in the northern hemisphere, the transport in the surface Ekman layer is to the right of the wind. ” These data showa pressure gradient sets up, resultingin an alongshore coastal jet, and an associatedonshore transport occurs within the bottom Ekman layer. Sep 21, 2017 · Estimates of the global ocean vertical velocities (Eulerian, eddy-induced, and residual) from a dynamically consistent and data-constrained ocean state estimate are presented and analyzed. The divergence of Ekman transport induces a vertical velocity known as Ekman pumping. Westward B. Illustration of coastal upwelling in the northern hemisphere. Upwelling increases along the coast of Peru. B. Characterization of upwelling by using wind-induced upwelling indexes (UIW) indicate the existence of Wind-driven gyres Ekman flow is only active in top 20-30m of the ocean. Correct. Also discover how observations of these currents are crucial in making climate predictions. Apr 1, 2010 · Abstract It is well known that along-isobath flow above a sloping bottom gives rise to cross-isobath Ekman transport and therefore sets up horizontal density gradients if the ocean is stratified. Sep 18, 2021 · The Ekman current is acts to grater depths due to viscous forces in the water mass. In this section, we consider the forces involved in the coupling of wind and ocean surface waters. The easterly trade winds cause northward Ekman transport just to the north of the equator and southward Ekman transport just to the south of the equator. The same was done for each flux component. Because of the Coriolis effect, surface waters move at an angle to the wind direction. In addition, we divide our analysis domain into the central and southern CCS to examine the extent of south-north exchange through transport of water masses by the surface and subsurface flow. These vertical fluxes are the results of mass balance and are caused by the horizontal water motions of divergence and convergence. They occur in various scales of sizes and durations. Consequences of Ekman transport Fig. [4] The increased mass of surface water creates high-pressure zones that push water downward. 2) Sv for the entire Arctic Basin, with ∼0. Ekman transport can result in both upwelling and downwelling. Review Check to review before finishing (will be flagged in Table of Contents) Question 10 of 18 (worth 1 point) Coastal upwelling of nutrient-rich water stimulates the growth of marine autotrophs (e. Apr 29, 2014 · Upwelling Steady winds blowing on the sea surface produce an Ekman layer that transports water at right angles to the wind direction. 16 that inertial flow is the special case of gradient flow in which the pressure Study with Quizlet and memorize flashcards containing terms like An indirect method of measuring ocean current is the use of, Surface or wind-driven currents move water primarily in a vertical direction in the ocean. The flow The upwelling and downwelling processes can be discussed under four fundamentally different initiation mechanisms. As a result, the pycnocline shoals towards the equator. 1). There is also an Ekman layer at the top (beneath the rotating lid), in which the radial component of the flow is opposite to that at the bottom boundary. An analogous derivation of the Ekman spiral can be shown for the ocean. A stratified, initially uniform, alongshelf flow undergoes a rapid adjustment with notable differences onshore and offshore of the shelf break. The classical explanation of these currents is that equatorward winds force Ekman flow offshore, which drives a shallow upwelling (order 200 meters deep) in a very narrow region adjacent to the coast (order 10 km). Vigorous upwelling zones are Study with Quizlet and memorize flashcards containing terms like The mass flow of ocean water that is driven by wind or gravity is referred to as ocean ____. The angle of the surface wind direction with the isobars is an important feature of both the atmospheric and oceanic Ekman spiral. In the west, the upwelled water is warm, but in the east the upwelled water is cold because the thermocline is so shallow. Sailors of ships noticed that icebergs move in a different direction than the wind. 5. May 21, 2018 · Ekman transport, part of Ekman motion theory first investigated in 1902 by Vagn Walfrid Ekman, refers to the wind-driven net transport of the surface layer of a fluid that, due to the Coriolis effect, occurs at 90° to the direction of the surface wind. Is this correct? The Ekman spiral refers to a structure of currents or winds near a horizontal boundary in which the flow direction rotates as one moves away from the boundary. Ekman transport driven upwelling and downwelling also occurs in the open ocean Just like along the coast, upwelling along the equator brings nutrient-rich water to the surface stimulating primary productivity. Essentially, on scales comparable to the mixed-layer depth, the pressure forces and advec-tion of momentum are small, so that the force applied by the wind is balanced by Coriolis forces associated with the o shore ow. Eastern coast B. For zero heat fluxes the release of available potential energy by baroclinic instabilities is strongest and leads, near the coast, to nearly full cancellation of the Ekman cross-shore circulation by eddy effects, i. This causes upwelling at the equator. , Dynamic topography can be used to determine current direction and velocity. To fully understand the ocean properties in eastern boundary upwelling systems, it is important to consider the depth of the source waters being upwelled, as Arctic explorer Fridtjof Nansen noticed something strange: icebergs tend to drift at an angle to the right of the prevailing wind direction. In this study, we investigate the Ekman pumping induced eddy vertical heat flux using the two formulations above. Nov 22, 2023 · True statements about Ekman spiral and Ekman transport include the opposite movement of water in deeper layers, the Coriolis effect causing angular movement of surface waters, Ekman transport to the right in the Northern Hemisphere, and the potential for upwelling and downwelling. , The Ekman spiral is similar to an eddy in that the water spirals downward like a whirlpool. Convergence and divergence of Ekman flow This horizontal flow causes vertical flow (upwelling and downwelling), which generate pressure gradients to great depths (1000 m) This process effectively communicates the effect of wind driven circulation to water flow at intermediate depths in the sea Critical thinking questions Can offshore wind (perpendicular to the coast) induce coastal upwelling/downwelling? Assume the Ekman layer is 50m thick; at 10m depth, Ekman flow is 90degree to the right of the wind. Aug 30, 2016 · This chapter describes the general physics driving coastal upwelling, various upwelling mechanisms and indicators (e. Over the shelf, a bottom boundary layer and an offshore bottom Ekman transport develop within an inertial period. Ekman transport can result in both upwelling and downwelling, and it is to the right of the wind direction in the Northern Hemisphere. For example, winds flowing toward the south produce upwelling along the California coast. Based on an eddy-rich climate model simulation, we find the eddy heat flux Ekman transport is the net motion of fluid as the result of a balance between Coriolis and turbulent drag forces. Lecture 12 - Upwelling and downwelling Learning Outcomes • Quick review of Ekman transport and May 4, 2021 · The classical Ekman pumping is well-known for its role in driving global ocean circulations. But (sub)mesoscale turbulence modulates offshore transport, hence the net upwelling rate. Downwelling is where surface water is forced Study with Quizlet and memorize flashcards containing terms like (1) 90, (3) 3 & mixed layer, pycnocline, and deep layer, (4) All the above are correct: "(1) basins and coasts (2) friction (3) Coriolis Effect" and more. - Ekman transport can result in both upwelling and In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction. Also, the zonal and meridional variations of hydrographic parameters along the SEAS during summer monsoon are studied in detail using in situ observations. This process plays a significant role in driving ocean currents and transporting water and nutrients vertically. Mar 18, 2024 · Abstract Coastal upwelling, driven by alongshore winds and characterized by cold sea surface temperatures and high upper-ocean nutrient content, is an important physical process sustaining some of the oceans’ most productive ecosystems. In the (a) Northern Hemisphere, a (b) ______ wind would produce upwelling and increase productivity along western coast of Africa. This page titled 11. Mar 13, 2025 · A. Study with Quizlet and memorize flashcards containing terms like According to the theory of Ekman Transport, ocean surface currents in the southern hemisphere will ____. 3 Sv net downwelling contributed mostly by the Canadian Sep 20, 2024 · The Indonesian Archipelago, straddling the equator, experiences complex wind patterns that drive significant upwelling events, a critical process influencing primary productivity and marine ecosystem dynamics in coastal regions. Bograd1 1NOAA Southwest Fisheries Science Center, Monterey, California, USA 2NOAA Earth System Research Laboratory, Boulder, Colorado, USA Jun 27, 2023 · Ekman transport causes the near-surface flow under a northerly wind in the Northern Hemisphere. View ESS 3 Lecture 12_Upwelling and downwelling. In 1D models of slope currents, geostrophic vertical shear resulting from horizontal buoyancy gradients within the BBL is predicted to eventually bring the bottom stress to zero, leading to a shutdown, or “arrest Nov 1, 2021 · Abstract Coastal upwelling rates are classically determined by the intensity of the upper-ocean offshore Ekman transport. the west wind drift Of the following statements about Ekman spiral and Ekman transport, which is/are true? The two factors that affect the Ekman spiral are the wind direction and the Coriolis effect. AI May 16, 2021 · For example, to assess the partial correlation of the Ekman pumping with the water mass exports, we first remove the signal of export correlated to freshwater and heat fluxes, and then determine an R2 for the residual export signal with Ekman pumping. - Upwelling increases along the coast of Peru. How are the currents of the Gulf Stream similar to meandering rivers? For the Ekman layer on a rigid surface, determine the maximum flow speed in terms of U, the flow speed above the layer, the altitude where this maximum occurs in terms of δ, and the direction of the flow at this altitude. , zero net mean upwelling flow. pdf from EARTHSS 5 at University of California, Irvine. Ekman transport is the same thing as thermohaline flow. This example is from the Northern Hemisphere. A. The geostropic flow is shown as concentric rings around the bulge in Fig. Pink arrow represents the alongshore wind stress and the blue arrow represents the offshore Ekman transport caused by the wind stress Study with Quizlet and memorize flashcards containing terms like downwelling, Describe upwelling and the conditions that produce it, Ekman transport and more. This layer is characterized by a spiral pattern of horizontal velocity and plays a crucial role in horizontal mass transport and associated oceanic processes. A simple theory is proposed using the framework of Zebiak-Cane (ZC) ocean model for insights into the dynamics of the upwelling annual cycle. 12. Compare the wind direction and the direction of the near-surface flow of water. 6: The Ekman Spiral and Geostrophic Flow is shared under a CC BY 4. Hazen1, Steven J. Mar 2, 2017 · The annual upwelling is an important component of the equatorial Atlantic annual cycle. Ekman transport primarily disrupts nutrient flow in the ocean, leading to a Oct 1, 2024 · The present study investigates the contributions of upwelling mechanisms (coastal upwelling from boundary divergence and Ekman pumping from spatially variable wind) at the northern margin of the Gulf of Cadiz (NMGoC) based on high-resolution wind. Coastal upwelling is more noticeable because it brings cooler subsurface water upward to the surface in Ekman transport moves the surface layer 90 o to the right of the wind, meaning the net Ekman transport is in an offshore direction. The results suggest that the coastline of the east coast of Peninsular Malaysia (ECPM) is affected by upwelling with spatiotemporal variations. Jan 1, 2016 · c. The prevailing westerlies increase as they flow over South America. Coastal upwelling and downwelling Ekman transport moves surface water away from shore, producing upwelling Ekman transport moves surface water towards shore, producing downwelling - Ekman flow phenomena occur, causing the movement of surface currents. During an El Niño event, water from the Pacific Warm Pool migrates across the equatorial South Pacific Ocean, from near Australia toward South Aug 2, 2017 · Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient Ekman layer transports, Ekman pumping, and the Sverdrup balance Geostrophic flow, or the flow produced by a balance between the pressure gradient force and the Coriolis force, is frictionless flow. Once the wind sets surface waters in motion as a current, the Coriolis effect, Ekman transport, and the configuration of the ocean basin modify the speed and direction of the current. Their energetics are notoriously complex, in particular near sloping topography, where the feedback between cross-slope Ekman transports, buoyancy forcing, and mixing affects the energy budget in ways that are not well understood. The Ekman layer is the layer in a fluid where the flow is the result of a balance between pressure gradient, Coriolis The three main drivers that work together to cause upwelling are wind, Coriolis effect, and Ekman transport. The nutrient-rich cold water brought to the surface by this process stimulates the growth and reproduction of phytoplankton – the primary producers in the Upwelling in the ocean is associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. , ENSO is an acronym for a repeating meteorological and oceanographic event that Ekman flow phenomena occur, causing the movement of surface currents. d. ” Feb 1, 2013 · We use the passive tracer fields to construct proxies for offshore transport, coastal upwelling strength and Ekman transport efficiency. [2005a] for a recent example on the Oregon Coast). Within an upwelling region, the water column below the Ekman layer is drawn upward. To clarify the wind strength of this occurrence, it is analyzed based on the value of windstress. In situ measurements In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction. These transports in turn eventually bring the along-isobath bottom velocity, hence bottom stress, to rest (“buoyancy arrest”) simply by means of the thermal wind shear. Winds along the eastern boundaries of all oceans are favorable to upwelling, probably as a result of topographic steering of the westerly winds as they reach land. ) When the fans are arranged to create an anticyclonic (cyclonic) vortex the ageostrophic flow at the surface is directed ‘to the right’ of the wind direction and hence induces convergence (divergence) and downwelling (upwelling): Fig. Therefore, upwelling and downwelling due to Ekman transport and pumping are leading mechanisms in the variability of the heat contents in the upper oceans. Each subsequent layer is forced by viscous forces (internal friction) to flow in the direction of the layer above. 2. From these graphics, we can see or infer each of the following Study with Quizlet and memorize flashcards containing terms like What effects does the surface wind pattern have on the circulation of the oceans?, What is the Ekman spiral? Explain why Ekman transport occurs. However, it is not clear how applicable this solution is for realistic stratified ocean with depth-dependent turbulent mixing coefficient (KM). Learning Objectives After reading this chapter you should be able to: identify the major ocean surface currents of the world (i. Ekman transport causes surface waters in equatorial waters to flow away from the equator, that is, toward the northwest in the Northern Hemisphere and toward the Dec 1, 2015 · Abstract Turbulent bottom Ekman layers are among the most important energy conversion sites in the ocean. , Describe the relationship between trade winds and biological productivity along the equator. Jan 10, 2011 · This newly suggested pathway follows the processes in succession as upwelling in the south Java coast, offshore Ekman drift and subduction into the thermocline centered on 20 ∘ S. AI generated definition based on: Free-Surface Flow, 2019 The vertical movements of ocean waters into or out of the base of the Ekman layer amount to less than one metre per day, but they are important since they extend the wind-driven effects into deeper waters. The 36 year mean of upwelling (downwelling) is 3. We induce cyclonic and anticyclonic circulation by blowing air over the surface of a rotating tank of water using fans co-rotating with the turntable, as sketched in Figure 1. Ekman, the surface layers are Ekman flow: terms (2) & (5) [&(3)] Weak friction will modify all of the above, and in the problem, the above balances are never exactly followed, only approximately, in different regions and at different times. It can Apr 13, 2023 · Second, wind stress curl (horizontal gradients in the wind) drives divergent flow near the ocean’s surface and consequently, upwelling (Ekman suction) that can extend 100–200 km farther SIO 210: Dynamics V Ekman & Atmosphere READING: DPO: Chapter 7. 5 Ekman layers Ekman layer convergence: upwelling and downwelling Wind patterns (atmosphere) Ocean’s Ekman transport and upwelling/10/29/19 Talley SIO 210 (2019)downwelling1 Wind forcing: initial response Feb 21, 2022 · This paper investigates the impact of equatorial wind stress on the equatorial Ekman transport during the Indian Ocean Dipole (IOD) mature phase. When surface water molecules move by the force of the wind, they, in turn, drag deeper layers of water molecules below them. Where Ekman transport moves surface waters away from the coast, surface waters are replaced by water that wells up from below in the process known as upwelling. Coastal upwelling is influenced by coastal geometry, wind directions, and the influence of the Coriolis effect (Ekman transport). Mar 12, 2025 · Study with Quizlet and memorize flashcards containing terms like How does a semi-permanent, subtropical atmospheric high-pressure system influence the salinity of the underlying surface ocean waters?, Describe the role played by Ekman transport in coastal upwelling. This article looks at the 'Ekman transport' effect—a wind-driven process that brings colder water to the coastline. Jacox1,2, Christopher A. The near-surface flow of water is about 90° to the ______ of the direction the wind is blowing. Eddy effects generally oppose the Ekman circulation, resulting in so-called “eddy cancellation,” a process well studied in the Southern Ocean. Eastward In Figure 7B-2, coastal downwelling occurs offshore of the ______, while coastal upwelling would be happening offshore of the opposite coast. 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