On the intrinsic shape of oceanic eddies derived from satellite altimetry

Ge, Chunhua; Han, Guiyan; Yang, Xueqing

doi:10.1016/j.rse.2019.04.011

Cited by 54 publications

(31 citation statements)

References 32 publications

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“…This becomes immediately evident in the angularly normalized map of Argo position with respect to the eddy centroid (Figure 14, see Chen et al. [2019a] for detailed procedures of an ellipse‐based eddy normalization). In contrast to the normal eddies (Figures 14a and 14c), the abnormal ones show a reversed pattern in the distribution of Argo float density: a central minimum for both AEs and CEs (Figures 14b and 14d).…”

Section: Discussionmentioning

confidence: 87%

“…The displacement of individual Argo float relative to the altimeter-derived eddy core may strongly affect the consistency between the observed results from the two systems in terms of eddy polarity. This becomes immediately evident in the angularly normalized map of Argo position with respect to the eddy centroid ( Figure 14, see Chen et al [2019a] for detailed procedures of an ellipse-based eddy normalization). In contrast to the normal eddies (Figures 14a and 14c), the abnormal ones show a reversed pattern in the distribution of Argo float density: a central minimum for both AEs and CEs (Figures 14b and 14d).…”

Section: Discussionmentioning

confidence: 89%

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Independent Eddy Identification With Profiling Argo as Calibrated by Altimetry

Chen

Huang

2021

JGR Oceans

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The technique of tandem altimetric mapping (e.g., Le Traon et al., 1998) has been effectively applied to systematic tracking of oceanic eddies on global or regional scales, leading to the construction of several interdecadal eddy data sets with a grid size of 1/8°-1/4° on daily or weekly basis beginning from early 1990s (e.g., Chelton et al., 2011; Faghmous et al., 2015; Tian et al., 2019). Substantial progress has been made in many areas of marine science following the availability of these unprecedented measurements in conjunction with other concurrent multidisciplinary data sources (e.g.,

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 89%

Independent Eddy Identification With Profiling Argo as Calibrated by Altimetry

Chen

Huang

2021

JGR Oceans

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“…The global method is generally based on the global topological properties of the flow field, which is different from the local method. McWilliam is one of the earliest scholars to study this kind of algorithm, which is based on the geometric profile characteristics of mesoscale eddies [27], but it loses eddies that deviate from the symmetrical structure [28]. Later, with the continuous maturity of remote sensing satellite technology, Chelton et al [15] used the pretreatment products of a remote sensing satellite altimeter to find the eddy center and the boundary of the eddy through closed contour search.…”

Section: Related Workmentioning

confidence: 99%

Oceanic Mesoscale Eddy Detection Method Based on Deep Learning

Duo

Wang

2019

Remote Sensing

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Oceanic mesoscale eddies greatly influence energy and matter transport and acoustic propagation. However, the traditional detection method for oceanic mesoscale eddies relies too much on the threshold value and has significant subjectivity. The existing machine learning methods are not mature or purposeful enough, as their train set lacks authority. In view of the above problems, this paper constructs a mesoscale eddy automatic identification and positioning network—OEDNet—based on an object detection network. Firstly, 2D image processing technology is used to enhance the data of a small number of accurate eddy samples annotated by marine experts to generate the train set. Then, the object detection model with a deep residual network, and a feature pyramid network as the main structure, is designed and optimized for small samples and complex regions in the mesoscale eddies of the ocean. Experimental results show that the model achieves better recognition compared to the traditional detection method and exhibits a good generalization ability in different sea areas.

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“…In this study, we used a Gaussian model for SLAs, which is the most typical model for ocean mesoscale eddies (Wang et al, 2015;Yang et al, 2019), to obtain the eddy properties. The SLA field h(x, y) with several adjacent eddies before merging can be expressed as (Yi et al, 2015;Chen et al, 2019) h…”

Section: Eddy Parametersmentioning

confidence: 99%

Two typical merging events of oceanic mesoscale anticyclonic eddies

Wang

Sun

et al. 2019

Ocean Sci.

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Abstract. The long-term theoretical “energy paradox” of whether the final state of two merging anticyclones contains more energy than the initial state is studied by considering two typical merging events of ocean mesoscale eddies. The results demonstrate that the total mass (volume), total circulation (area integration of vorticity), and total angular momentum (AM) are conserved if the orbital AM relative to the center of mass is taken into account as the eddies rotate around the center of mass before merging. For subsurface merging, the mass trapped by the Taylor–Proudman effect above the subsurface eddies should also be included. Both conservation laws of circulation and orbital AM have been overlooked in previous theoretical studies. As a result of fusion during merging, the total eddy kinetic energy decreases slightly. In contrast, the total eddy potential energy (EPE) increases after merging. The increase in EPE is mostly supported by the loss of gravitational potential energy (PE) via eddy sinking below the original level prior to merging. This implies that the merging of eddies requires background gravitational PE to be converted to EPE. In contrast, the vorticity and enstrophy consequently decrease after merging. Thus, the eddy merging effect behaves as a “large-scale energy pump” in an inverse energy cascade. It is noted that eddy conservation and conversion laws depend on the laws of physical dynamics, even if additional degrees of freedom can be provided in a mathematical model.

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On the intrinsic shape of oceanic eddies derived from satellite altimetry

Cited by 54 publications

References 32 publications

Independent Eddy Identification With Profiling Argo as Calibrated by Altimetry

Independent Eddy Identification With Profiling Argo as Calibrated by Altimetry

Oceanic Mesoscale Eddy Detection Method Based on Deep Learning

Two typical merging events of oceanic mesoscale anticyclonic eddies

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