Evolution of a physical and biological front from upwelling to relaxation

Zhang, Yanwu; Bellingham, James; Ryan, John P.; Godin, M. A.

doi:10.1016/j.csr.2015.08.005

Cited by 15 publications

(14 citation statements)

References 24 publications

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“…In contrast, upwelling shadows [Graham and Largier, 1997;Roughan et al, 2005] offer environments sheltered from coastal upwelling where reduced offshore drift is exploited by ecosystems. Enrichment by nearby upwelling waters is indirect and intermittent in these sectors [Zhang et al, 2015].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of a “low‐enrichment high‐retention” upwelling center over the southern Senegal shelf

Ndoye

Capet

Estrade

et al. 2017

Geophysical Research Letters

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Senegal is the southern tip of the Canary upwelling system. Its coastal ocean hosts an upwelling center which shapes sea surface temperatures between latitudes 12° and 15°N. Near this latter latitude, the Cape Verde headland and a sudden change in shelf cross‐shore profile are major sources of heterogeneity in the southern Senegal upwelling sector (SSUS). SSUS dynamics is investigated by means of Regional Ocean Modeling System simulations. Configuration realism and resolution (Δx≈ 2 km) are sufficient to reproduce the SSUS frontal system. Our main focus is on the 3‐D upwelling circulation which turns out to be profoundly different from 2‐D theory: cold water injection onto the shelf and upwelling are strongly concentrated within a few tens of kilometers south of Cape Verde and largely arise from flow divergence in the alongshore direction; a significant fraction of the upwelled waters are retained nearshore over long distances while travelling southward under the influence of northerly winds. Another source of complexity, regional‐scale alongshore pressure gradients, also contributes to the overall retention of upwelled waters over the shelf. Varying the degree of realism of atmospheric and oceanic forcings does not appreciably change these conclusions. This study sheds light on the dynamics and circulation underlying the recurrent sea surface temperature pattern observed during the upwelling season and offers new perspectives on the connections between the SSUS physical environment and its ecosystems. It also casts doubt on the validity of upwelling intensity estimations based on simple Ekman upwelling indices at such local scales.

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Section: Introductionmentioning

confidence: 99%

Dynamics of a “low‐enrichment high‐retention” upwelling center over the southern Senegal shelf

Ndoye

Capet

Estrade

et al. 2017

Geophysical Research Letters

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“…The Tethys long-range AUV was programmed to perform a sawtooth, also referred to as a yo-yo, trajectory in the vertical two-dimensional plane [6]. They developed an adaptive algorithm using the AUV to autonomously detect an upwelling and track the movement of the front on a fixed latitude [6,16,[90][91][92]. The core of the method is to differentiate two types of water masses in an upwelling water column and a strongly stratified water column.…”

Section: Front and Boundary Determinationmentioning

confidence: 99%

AUV Adaptive Sampling Methods: A Review

2019

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Autonomous underwater vehicles (AUVs) are unmanned marine robots that have been used for a broad range of oceanographic missions. They are programmed to perform at various levels of autonomy, including autonomous behaviours and intelligent behaviours. Adaptive sampling is one class of intelligent behaviour that allows the vehicle to autonomously make decisions during a mission in response to environment changes and vehicle state changes. Having a closed-loop control architecture, an AUV can perceive the environment, interpret the data and take follow-up measures. Thus, the mission plan can be modified, sampling criteria can be adjusted, and target features can be traced. This paper presents an overview of existing adaptive sampling techniques. Included are adaptive mission uses and underlying methods for perception, interpretation and reaction to underwater phenomena in AUV operations. The potential for future research in adaptive missions is discussed.

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“…Upwelling fronts support enriched phytoplankton and zooplankton populations, as well as physical processes that can locally enhance plankton aggregation and nutrient supply (Woodson et al, 2009;Ryan et al, 2010bRyan et al, ,c, 2014Harvey et al, 2012), thus playing an important role in structuring ocean ecosystems. Detection and sampling of upwelling fronts is important for ecological studies of coastal upwelling systems (Zhang et al, 2015). Upwelling fronts move due to variations in wind and ocean circulation, as shown in Figure 3.…”

Section: Classifying and Sampling Distinct Water Types Across A Coastmentioning

confidence: 99%

Targeted Sampling by Autonomous Underwater Vehicles

et al. 2019

Self Cite

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In the vast ocean, many ecologically important phenomena are temporally episodic, localized in space, and move according to local currents. To effectively study these complex and evolving phenomena, methods that enable autonomous platforms to detect and respond to targeted phenomena are required. Such capabilities allow for directed sensing and water sample acquisition in the most relevant and informative locations, as compared against static grid surveys. To meet this need, we have designed algorithms for autonomous underwater vehicles that detect oceanic features in real time and direct vehicle and sampling behaviors as dictated by research objectives. These methods have successfully been applied in a series of field programs to study a range of phenomena such as harmful algal blooms, coastal upwelling fronts, and microbial processes in open-ocean eddies. In this review we highlight these applications and discuss future directions.

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Evolution of a physical and biological front from upwelling to relaxation

Cited by 15 publications

References 24 publications

Dynamics of a “low‐enrichment high‐retention” upwelling center over the southern Senegal shelf

Dynamics of a “low‐enrichment high‐retention” upwelling center over the southern Senegal shelf

AUV Adaptive Sampling Methods: A Review

Targeted Sampling by Autonomous Underwater Vehicles

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