Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised

Purpose. The main goal of this study is to analyse the seasonal variability of meso-scale eddy activity in the north tropical Indian Ocean. The selected area coincides with the location of POLYGON-67 experiment where the mesoscale eddies of the open ocean were first discovered. Methods and Result...

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Main Authors: G.I. Shapiro, J.M. Gonzalez-Ondina
Format: Article
Language:English
Published: Federal State Budget Scientific Institution «Marine Hydrophysical Institute of RAS» 2020-12-01
Series:Physical Oceanography
Subjects:
Online Access:http://physical-oceanography.ru/repository/2020/6/en_202006_02.pdf
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spelling doaj-8899943e4f1a459bb83535ee0830547f2021-06-29T08:18:10ZengFederal State Budget Scientific Institution «Marine Hydrophysical Institute of RAS»Physical Oceanography1573-160X2020-12-0127657358910.22449/1573-160X-2020-6-573-589Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 RevisedG.I. Shapiro0J.M. Gonzalez-Ondina1University of Plymouth, Plymouth, United KingdomUniversity of Plymouth, Plymouth, United KingdomPurpose. The main goal of this study is to analyse the seasonal variability of meso-scale eddy activity in the north tropical Indian Ocean. The selected area coincides with the location of POLYGON-67 experiment where the mesoscale eddies of the open ocean were first discovered. Methods and Results. The variability of mesoscale eddy kinetic energy in surface ocean layer, enstrophy of larger scale circulation, spatial and temporal patterns of surface currents and surface winds are jointly analysed using a 20-year long daily time series of eddy-resolving ocean reanalysis data obtained from EU Copernicus Marine Environment Monitoring Service and climatic wind data from US National Oceanographic and Atmospheric Administration. The fast mesoscale and slow large-scale processes are separated using a Savitsky – Golay filter with the cut-off time of 103 days which corresponds to a local minimum in the full kinetic energy power spectrum. In contrast to other parts of the tropical ocean, the seasonal variability of EKE exhibits 2 maxima – the largest being in April, and the secondary being in October which are related to the maxima in enstrophy of larger scale currents. Conclusions. The double peak variability in EKE corresponds to the seasonal variability of large scale enstrophy and monsoon wind circulation and supports a hypothesis that the main mechanism of EKE generation is barotropic instability of larger scale currents. The EKE variability within P67 is mostly controlled by advection of energy from neighbouring areas, and to a lesser extent by local generation.http://physical-oceanography.ru/repository/2020/6/en_202006_02.pdfreviewmesoscale eddiesrossby wavesbaroclinic instabilityeddy barotropizationdrifterssatellite altimetryocean circulationmeso-scale eddiesseasonal variabilityreanalysisbarotropic instabilityindian ocean
collection DOAJ
language English
format Article
sources DOAJ
author G.I. Shapiro
J.M. Gonzalez-Ondina
spellingShingle G.I. Shapiro
J.M. Gonzalez-Ondina
Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
Physical Oceanography
review
mesoscale eddies
rossby waves
baroclinic instability
eddy barotropization
drifters
satellite altimetry
ocean circulation
meso-scale eddies
seasonal variability
reanalysis
barotropic instability
indian ocean
author_facet G.I. Shapiro
J.M. Gonzalez-Ondina
author_sort G.I. Shapiro
title Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
title_short Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
title_full Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
title_fullStr Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
title_full_unstemmed Seasonal Variability of Eddy Kinetic Energy in the Central Indian Ocean: POLYGON-67 Revised
title_sort seasonal variability of eddy kinetic energy in the central indian ocean: polygon-67 revised
publisher Federal State Budget Scientific Institution «Marine Hydrophysical Institute of RAS»
series Physical Oceanography
issn 1573-160X
publishDate 2020-12-01
description Purpose. The main goal of this study is to analyse the seasonal variability of meso-scale eddy activity in the north tropical Indian Ocean. The selected area coincides with the location of POLYGON-67 experiment where the mesoscale eddies of the open ocean were first discovered. Methods and Results. The variability of mesoscale eddy kinetic energy in surface ocean layer, enstrophy of larger scale circulation, spatial and temporal patterns of surface currents and surface winds are jointly analysed using a 20-year long daily time series of eddy-resolving ocean reanalysis data obtained from EU Copernicus Marine Environment Monitoring Service and climatic wind data from US National Oceanographic and Atmospheric Administration. The fast mesoscale and slow large-scale processes are separated using a Savitsky – Golay filter with the cut-off time of 103 days which corresponds to a local minimum in the full kinetic energy power spectrum. In contrast to other parts of the tropical ocean, the seasonal variability of EKE exhibits 2 maxima – the largest being in April, and the secondary being in October which are related to the maxima in enstrophy of larger scale currents. Conclusions. The double peak variability in EKE corresponds to the seasonal variability of large scale enstrophy and monsoon wind circulation and supports a hypothesis that the main mechanism of EKE generation is barotropic instability of larger scale currents. The EKE variability within P67 is mostly controlled by advection of energy from neighbouring areas, and to a lesser extent by local generation.
topic review
mesoscale eddies
rossby waves
baroclinic instability
eddy barotropization
drifters
satellite altimetry
ocean circulation
meso-scale eddies
seasonal variability
reanalysis
barotropic instability
indian ocean
url http://physical-oceanography.ru/repository/2020/6/en_202006_02.pdf
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AT jmgonzalezondina seasonalvariabilityofeddykineticenergyinthecentralindianoceanpolygon67revised
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