The influence of the Plata, second largest river in South America, extends along a coastal strip 1300 km. Historical hydrographic and wind data numerical simulations are combined to determine seasonal interannual variability Plata plume its relationship magnitude discharge intensity direction stress. Our results indicate that is controlled by alongshore component During El Niño effects precipitation anomalies tend compensate each other, preventing anomalous northeastward extensions...

This article discusses the results of a suite numerical simulations oceanic circulation in Southwestern Atlantic Shelf region that are aimed to characterize its mean and seasonal variability determine dynamical mechanisms controlling them. Our experiments indicate south 40°S is dominated by general northeastward flow southern portion shelf, which controlled discharges from Magellan Straits, tidal mixing, wind forcing, offshore influence Malvinas Current farther north. The 33°S presents...

Abstract. The oceanic circulation over the southwestern Atlantic shelf is influenced by large tidal amplitudes, substantial freshwater discharges, high wind speeds and – most importantly its proximity to two of largest western boundary currents world ocean: Brazil Malvinas currents. This review article aims discriminate dynamical processes controlling interaction between this extensive region deep-ocean. discussion focused on broad regions: South Bight north, Patagonia south. exchanges...

This article analyzes the barotropic circulation in Southwestern Atlantic Shelf using a three‐dimensional numerical model forced with winds and tides. South of 40°S, shelf is dominated by propagation semidiurnal In this region diurnal tides are generally weak, except at edge where they resonate northward propagating, continental waves. North tidal relatively mainly driven winds. The wind‐driven annual mean characterized broad northeastward flow south approximately 40°S southwestward farther...

Abstract The term “downwelling currents” refers to currents with a downslope mass flux in the bottom boundary layer. Examples are Malvinas and Southland Currents Southern Hemisphere Oyashio Northern Hemisphere. Although many of these generate same type highly productive ecosystems that is associated upwelling regimes, mechanism may drive such remains unclear. In this article, it postulated interaction between downwelling current continental slope generates shelfbreak upwelling. proposed...

Abstract. The Patagonia continental shelf located off southeastern South America is bounded offshore by the Malvinas Current, which extends northward from northern Drake Passage (~55° S) to nearly 38° S. transition between relatively warm-fresh waters and Subantarctic Waters western boundary current characterized a thermohaline front extending 2500 km. We use satellite derived sea surface temperature, chlorophyll-a data combined with hydrographic drifter document intrusions of slope onto...

Abstract The Santa Marta Grande Cape (CSM) area, a relatively steep and narrow continental shelf off southeast Brazil, is under the influence of Brazil Current intense seasonal variations wind field that affect composition water masses their circulation. Hydrographic data, satellite‐derived stress, numerical simulations are used to characterize shorter period variability oceanographic conditions CSM, in area between 27°S 30°S. study focused on upwelling episodes dynamical mechanisms...

A high-resolution model is used to characterize the dominant patterns of sea surface salinity (SSS) variability generated by freshwater discharges Rio de la Plata (RdlP) and Patos/Mirim Lagoon in southwestern Atlantic region. We identify three modes SSS variability. The first two, which have been discussed previous studies, represent seasonal interannual variations plumes over continental shelf. third mode variability, has not hitherto, represents exchanges between shelf deep ocean....

Abstract Altimeter sea surface height (SSH) fields are analyzed to define and discuss the seasonal circulation over wide continental shelf in SW Atlantic Ocean (27°–43°S) during 2001–2012. Seasonal variability is low south of Rio de la Plata (RdlP), where winds currents remain equatorward for most year. Winds central northern parts our domain also autumn winter but reverse become poleward spring summer. Transports water deep ocean strongest summer offshore southeast RdlP. Details flow...

The objective of this study is to evaluate the performance several open boundary conditions applied Princeton ocean model. focus on passive external mode, i.e., that are when mean flow at unknown and values variables must be assumed or extrapolated from interior solution. Three types (OBCs) tested: (1) radiation conditions, (2) characteristic methods, (3) relaxation schemes. Numerical experiments conducted in a zonal channel include different forms bottom topography. designed emphasize...

Satellite-derived sea surface salinity (SSS) data from Aquarius and SMOS are used to study the shelf-open ocean exchanges in western South Atlantic near 35°S. Away tropics, these cause largest SSS variability throughout Atlantic. The reveal a well-defined seasonal pattern of during analyzed period location export low-salinity shelf waters. In spring summer, waters over expand offshore transferred open primarily southeast river mouth (from 36°S 37°30′S). contrast, fall winter, extend along...

The velocity structure of the Malvinas Current is described based on analysis high‐resolution hydrographic data and direct current observations. show that though width exceeds 150 km, flow concentrated in two relatively narrow (~10–20 km) jets. Within these cores, observations indicate surface velocities exceeding 0.5 m.s −1 . Surface drifter, satellite‐derived mean dynamic topography, sea temperature suggest high‐velocity jets are also ubiquitous features time circulation. Both appear to be...

Abstract A suite of high‐resolution numerical simulations characterizes the oceanic circulation in Burdwood Bank, a shallow seamount located northeastern end Drake Passage. Model analysis shows energetic upwelling and mixing uplifting deep benthic waters into photic layer. Tides Antarctic Circumpolar Current are primary drivers bank's circulation. Tidal forcing is main driver for entrainment upper layers bank local wind detrainment these ocean. Passive tracer diagnostics suggest that...

Abstract. The Humboldt Large Marine Ecosystem (HLME) and Patagonian (PLME) are the two largest marine ecosystems in Southern Hemisphere respectively located along Pacific Atlantic coasts of southern South America. This work investigates exchange between these LMEs its seasonal interannual variability by employing numerical model results offline particle-tracking algorithms. Our analysis suggests a general poleward transport on region HLME, well-defined flux from to Atlantic, equatorward...

It has been proposed that vertical movements of planktonic organisms coupled to a horizontally or vertically stratified circulation pattern could describe retention mechanism, with ecological advantages such as favoring recruitment success. The Patagonian stock the Argentine hake Merluccius hubbsi spawns mainly from January February in relation highly productive tidal frontal system. Although fish eggs and larvae previously hypothesized for this system, it not fully proven its mechanisms...

In this modeling study we investigate the dynamical mechanisms controlling spreading of Magellan Plume, which is a low‐salinity tongue that extends along Patagonian Shelf. Our results indicate overall characteristics plume (width, depth, rate, etc.) are primarily influenced by tidal forcing, manifests through mixing and residual currents. Tidal forcing produces homogenization plume's waters an offshore displacement its salinity front. The interaction between wind‐forcing reinforces...

Abstract This modeling study analyzes the circulation over Agulhas Bank (AB). It is suggested that time mean bank primarily driven by inflow of shelf waters from northeastern region, and not local forcing as previously postulated. Seasonal variations temperature salinity fields are highly correlated with atmospheric forcing. Currents shift inshore during winter, returning to its original position summer. The equatorward flow in western AB, which includes a deep, unreported, countercurrent,...

This article discusses the results of an experimental survey on performance a select group open boundary conditions (OBCs) for three‐dimensional, primitive equation models. The focus is passive conditions, where model response at boundaries dictated by interior dynamics. OBCs tested in series numerical experiments conducted rotating channel which includes variable bottom topography and density stratification. are selected to enhance nonlinear phenomena that comprises advection propagation...

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