Detecting the transport barriers in the Pearl River estuary, Southern China with the aid of Lagrangian coherent structures

Wang, Xing; Zhan, Haigang; Cai, Shuqun; Zhan, Weikang; Ni, Peitong

doi:10.1016/j.ecss.2018.03.010

Cited by 11 publications

(9 citation statements)

References 36 publications

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“…The use of Finite‐size Lyapunov‐exponent (FSLE) field maxima to determine LCS has become a valuable tool for visualizing the complex structure of ocean circulation at various spatial and temporal scales (Baudena et al., 2019; De Monte et al., 2012; Prants et al., 2014). LCS analyses have been used to predict the transport of contaminants (such as oil spills), as well as to help understand the dynamical control on the trophic chain between primary producers (Drouin et al., 2019; Lehahn et al., 2007; Olascoaga et al., 2008; Wei et al., 2018) and higher‐level predators (Della Penna et al., 2015; Tew‐Kai et al., 2009; Scales et al., 2018). In this study geostrophic‐based LCS analyses, combined with ocean color remote sensing and numerical simulation results, are used to explore the dynamics controlling formation, stability, and breakdown of the transport barrier for C. finmarchicus populations on the shelf and off‐shelf regions near the Lofoten‐Vesterålen Islands.…”

Section: Introductionmentioning

confidence: 99%

Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring

Dong

Zhou

et al. 2021

JGR Oceans

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Large aggregations of the copepod Calanus finmarchicus occur each spring in the shelf‐slope‐oceanic regions off the Lofoten‐Vesterålen Islands where productive fisheries have traditionally supported local economies. The retention and off‐shelf transport of populations of C. finmarchicus populations were studied by analyzing ocean color remote sensing, satellite altimetry data, and Lagrangian Coherent Structures (LCS) between 2010 and 2019. Our analysis revealed the existence of a transport barrier reoccurring at the shelf break that retains C. finmarchicus on the shelf for 30–70 days in the spring when C. finmarchicus were seasonally ascending to the surface layer. The analysis of baroclinic and barotropic energy conversions indicated that the topographically steered Norwegian Atlantic Current is the primary mechanism in the formation of the transport barrier, which restricts exchanges of C. finmarchicus populations between shelf and oceanic waters. In the mid‐ to late April, an increase in baroclinicity leads to an increase in mesoscale eddies generated on the shelf break near Lofoten‐Vesterålen Islands, breaking down transport barriers and causing off‐shelf transport of C. finmarchicus. The transport barrier predictably reoccurs in early spring which supports the entrapment of C. finmarchicus in the shelf region.

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Section: Introductionmentioning

confidence: 99%

Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring

Dong

Zhou

et al. 2021

JGR Oceans

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“…Therefore, continuous improvement of the predictability of the fate of material in coastal waters is important for keeping sustainability of the relevant ecosystem [D'Asaro et al, 2018] The horizontal spreading and mixing processes of various substances such as floating debris, pollutant spills, and plankton patchiness in estuaries are impacted by underlying flow dynamics. In time-dependent, chaotic flow, an Eulerian viewpoint provides limited information about the transport of material, therefore, it is natural to approach the problems of material transport in a Lagrangian framework [Vandenbulcke et al, 2009;Wei et al, 2018]. Lagrangian particle tracking is applied to examine the fate, source and mixing of materials in many geophysical flows [Fredj et al, 2016] including oil and debris in the near shore [Suneel et al, 2016;Qiao et al, 2019].…”

Section: Introductionmentioning

confidence: 99%

“…The LCS concept has been used to understand a range of processes and problems in oceanic flow [d'Ovidio et al, 2004;Prants, 2014]. Coastal tidal flows have recently been a focus of studies using LCSs [Huhn et al, 2012;Wei et al, 2018;Lacorata et al, 2019]. These flows are particularly challenging due to complex three-dimensional boundaries, the interplay of unsteady forcings of wind, tide and river discharge as well as their interaction with physical features, including bathymetry and island structures [Suara et al, 2017].…”

Section: Introductionmentioning

confidence: 99%

“…More robust and exact methods for identification of LCS are in the literature [Haller, 2011]. A similar FTLE method was applied to identify transport barriers in coastal waters using HF radar derived surface velocity [Lekien et al, 2005;Coulliette et al, 2007], and numerical model velocity [Huhn et al, 2012;Wei et al, 2018]. The concept is applied here to identify transport barriers in a tidal embayment using the Eulerian velocity obtained from a hydrodynamic model velocity field and to examine the role of wind and tides on transport barriers in such a system [Yu et al, 2016].…”

Section: Introductionmentioning

confidence: 99%

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Material and debris transport patterns in Moreton Bay, Australia: The influence of Lagrangian coherent structures

Suara

Khanarmuei

Ghosh

et al. 2020

Science of The Total Environment

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Coastal tidal estuaries are vital to the exchange of energy and material between inland waters and the open ocean.Debris originating from the land and ocean enter this environment and are transported by currents (river outflow and tide), wind, waves and density gradients. Understanding and predicting the source and fate of such debris has considerable environmental, economic and visual importance. We show that this issue can be addressed using the Lagrangian coherent structures (LCS) technique which is highly robust to hydrodynamic model uncertainties.Here we present a comprehensive study showing the utility of this approach to describe the fate of floating material in a coastal tidal embayment. An example is given from Moreton Bay, a semi-enclosed subtropical embayment with high morphologic, ecological and economic significance to Southeast Queensland, Australia. Transport barriers visualised by the LCS create pathways and barriers for material transport in the embayment. It was found that the wind field modified both the rate attraction and location of the transport barriers. One of the key outcomes is the demonstration of the significant role of islands in partitioning the transport of material and mixing within the embayment. The distribution of the debris sources along the shoreline are explained by the relative location of the LCS to the shoreline. Therefore, extraction of LCS can help to predict sources and fate of anthropogenic marine debris and thus, serve as a useful way for effective management of vulnerable regions and marine protected areas.

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“…It has proven to be a valuable and appropriate tool for simplifying the transport and mixing in fluid flows and diagnosing the transport properties of materials (Branicki and Wiggins, 2010;Wei et al, 2013). Many methods have been proposed to identify LCSs, and finite-time Lyapunov exponents (FTLEs) are widely used (Wei et al, 2013;Berta et al, 2014;Wei et al, 2018). The ridges in the FTLE fields can be used as barriers to mass transport and identify the LCSs in the flow field (Haller and Yuan, 2000;Haller, 2015;Wei et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamical transport structure and lagrangian connectivity of circulations in the Pearl River Estuary

Chu

Liu

et al. 2022

Front. Mar. Sci.

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Using a three-dimensional (3D) hydrodynamic model, this study explored the seasonal hydrodynamic transport structure in the Pearl River Estuary and illustrated the intrinsic connectivity under multiscale motions from a Lagrangian perspective. Generally, the surface Lagrangian residual current (UL) is uniformly southwestward/southeastward in summer/winter, with a stronger intensity in the lower estuary. The bottom UL features in the southeastward direction in the upper estuary and northwest direction in the lower estuary. The fluvial–tide interaction line advances southeastward and northwestward in summer and winter, respectively. The UL captured the major transport processes and was in good agreement with the mean surface sediment transport patterns. In the transition region between Lantau Island and Neilingding Island, where it is largely affected by the interaction between the periodic tidal current and river discharge, the spatially averaged UL showed intensified intratidal variations and had a larger difference with the locally temporally averaged Eulerian residual current. The remarkable Lagrangian coherent structures that illustrated the transport paths and transport convergence regions were identified, which are generally consistent with the bottom sediment depocenters. Based on the Lagrangian connectivity analysis, it was revealed that a barrier between the western and eastern estuaries existed, which was weakened by the strong river discharge during summer. Two convergence regions near the Macau and Hong Kong waters were identified, where the sediment and pollutants easily settled. The study demonstrated the importance of the Lagrangian view in understanding the hydrodynamic process and transport structure in the estuary–shelf regions.

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Detecting the transport barriers in the Pearl River estuary, Southern China with the aid of Lagrangian coherent structures

Cited by 11 publications

References 36 publications

Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring

Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring

Material and debris transport patterns in Moreton Bay, Australia: The influence of Lagrangian coherent structures

Hydrodynamical transport structure and lagrangian connectivity of circulations in the Pearl River Estuary

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