An Improved Automatic Algorithm for Global Eddy Tracking Using Satellite Altimeter Data

Sun, Miao; Tian, Feng; Liu, Yingjie; Chen, Ge

doi:10.3390/rs9030206

Cited by 49 publications

(22 citation statements)

References 48 publications

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“…But a major breakthrough is that it allows for the first time an oceanic eddy to be individually tracked during its lifetime. Taking advantage of such an unprecedented data product, a number of automated procedures have been developed for identifying and tracking mesoscale eddies globally and/or regionally (e.g., Chelton et al, 2011;Isern-Fontanet et al, 2003;Liu et al, 2016;Mason et al, 2014;Penven et al, 2005;Sun et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Contrasting Short‐Lived With Long‐Lived Mesoscale Eddies in the Global Ocean

Chen

Han

2019

JGR Oceans

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The increase of temporal resolution from weekly to daily and spatial resolution from ~1° to ~(1/4)° in merged altimeter sea surface height data along with their over two decades of time series opens an unprecedented opportunity to reveal the “spectrum” of eddy variabilities from days to years in time and from mesoscale to semimesoscale in space. Eddies with a lifetime shorter than 1 month or longer than 1 year are classified here as short lived and long lived, respectively. Contrasting the variabilities of short‐ and long‐lived eddies could be an effective way to explore their geographic origins and dynamic formations. In the time domain, the population fluctuations of short‐ and long‐lived eddies are basically dominated by annual and interannual component, respectively. The magnitude of kinematic and dynamic properties of oceanic eddies is positively correlated with their lifetime in general. Statistically, the properties of short‐lived (long‐lived) eddies experience a symmetric (an asymmetric) growth and decay with a single flat peak during their life cycles. In the space domain, eddy occurrence is observed as a high probability event, which can reach every corner of the ocean. However, homes of short‐ and long‐lived eddies are highly regionalized and are geographically separated. A prominent “young eddy belt” is observed in the tropical oceans for the first time. These findings suggest two fundamental characteristics with regard to short‐ and long‐lived mesoscale eddies: residing in largely separated geographic zones under different mechanisms while following a similar pattern of intrinsic life cycle in terms of property evolution.

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Section: Introductionmentioning

confidence: 99%

Contrasting Short‐Lived With Long‐Lived Mesoscale Eddies in the Global Ocean

Chen

Han

2019

JGR Oceans

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“…Especially eddy identification and tracking from sea surface height fields has already developed maturity and has been applied to actual eddy studies (Chaigneau et al, 2008;Isern-Fontanet et al, 2003;Nencioli et al, 2010). More and more research uses a purely geometric method based on sea level anomaly (SLA) that is more accurate and is becoming more of a mainstream method in recent years (Faghmous et al, 2015;Souza et al, 2011;Sun et al, 2017). The purely geometric method for eddy identification stems from Chelton et al (2011), and some developments and practical improvements have been made by many researchers (Cui et al, 2016;Mason et al, 2014;Schlax and Chelton, 2016).…”

Section: Introductionmentioning

confidence: 99%

Multicore structures and the splitting and merging of eddies in global oceans from satellite altimeter data

et al. 2019

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Abstract. This study investigated the statistics of eddy splitting and merging in the global oceans based on 23 years of altimetry data. Multicore structures were identified using an improved geometric closed-contour algorithm of sea surface height. Splitting and merging events were discerned from continuous time series maps of sea level anomalies. Multicore structures represent an intermediate stage in the process of eddy evolution, similar to the generation of multiple nuclei in a cell as a preparatory phase for cell division. Generally, splitting or merging events can substantially change (by a factor of 2 or more) the eddy scale, amplitude, and eddy kinetic energy. Specifically, merging (splitting) generally causes an increase (decrease) of eddy properties. Multicore eddies were found to tend to split into two eddies with different intensities. Similarly, eddy merging is not an interaction of two equal-intensity eddies, and it tends to manifest as a strong eddy merging with a weaker one. A hybrid tracking strategy based on the eddy overlap ratio, considering both multicore and single-core eddies, was used to confirm splitting and merging events globally. The census revealed that eddy splitting and merging do not always occur most frequently in eddy-rich regions; e.g., their frequencies of occurrence in the Antarctic Circumpolar Current and western boundary currents were found to be greater than in midlatitude regions (20–35∘) to the north and south. Eddy splitting and merging are caused primarily by an unstable configuration of multicore structures due to obvious current– or eddy–topography interaction, strong current variation, and eddy–mean flow interaction.

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“…It has an average depth of 1212 m and a maximum depth of 5377 m. Considering that the research priority of this study is the oceanic eddy, we focus on the region (5 • N-23 • N, 108 • E-121 • E), and define this area as the SCS. It is proven that there are many mesoscale eddies in the SCS, based on hydrographic surveys [1], satellite observations [2][3][4][5][6] and numerical simulation [7]. In practice, since Dale [8] found the first mesoscale eddy in the SCS, studies over the past 60 years have proven that the SCS is a hot spot of intense eddy activity.…”

Section: Introductionmentioning

confidence: 99%

Vertical Structure Anomalies of Oceanic Eddies and Eddy-Induced Transports in the South China Sea

et al. 2018

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Using satellite altimetry sea surface height anomalies (SSHA) and Argo profiles, we investigated eddy's statistical characteristics, 3-D structures, eddy-induced physical parameter changes, and heat/freshwater transports in the South China Sea (SCS). In total, 31,744 cyclonic eddies (CEs, snapshot) and 29,324 anticyclonic eddies (AEs) were detected in the SCS between 1 January 2005 and 31 December 2016. The composite analysis has uncovered that changes in physical parameters modulated by eddies are mainly confined to the upper 400 m. The maximum change of temperature (T), salinity (S) and potential density (σ θ) within the composite CE reaches −1.5 • C at about 70 m, 0.1 psu at about 50 m, and 0.5 kg m −3 at about 60 m, respectively. In contrast, the maximum change of T, S and σ θ in the composite AE reaches 1.6 • C (about 110 m), −0.1 psu (about 70 m), and −0.5 kg m −3 (about 90 m), respectively. The maximum swirl velocity within the composite CE and AE reaches 0.3 m s −1. The zonal freshwater transport induced by CEs and AEs is (373.6 ± 9.7)×10 3 m 3 s −1 and (384.2 ± 10.8)×10 3 m 3 s −1 , respectively, contributing up to (8.5 ± 0.2)% and (8.7 ± 0.2)% of the annual mean transport through the Luzon Strait.

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An Improved Automatic Algorithm for Global Eddy Tracking Using Satellite Altimeter Data

Cited by 49 publications

References 48 publications

Contrasting Short‐Lived With Long‐Lived Mesoscale Eddies in the Global Ocean

Contrasting Short‐Lived With Long‐Lived Mesoscale Eddies in the Global Ocean

Multicore structures and the splitting and merging of eddies in global oceans from satellite altimeter data

Vertical Structure Anomalies of Oceanic Eddies and Eddy-Induced Transports in the South China Sea

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