Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean
Abstract The baroclinic component of the sea surface height, referred to as steric height, is governed by geostrophically balanced motions and unbalanced internal waves, and thus is an essential indicator of ocean interior dynamics. Using yearlong measurements from a mooring array, we assess the dis...
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| Format: | Article |
| Language: | English |
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Wiley
2024-03-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2023GL106480 |
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| author | Xiujie Zhang Xiaolong Yu Aurélien L. Ponte Wenping Gong |
| author_facet | Xiujie Zhang Xiaolong Yu Aurélien L. Ponte Wenping Gong |
| author_sort | Xiujie Zhang |
| collection | DOAJ |
| description | Abstract The baroclinic component of the sea surface height, referred to as steric height, is governed by geostrophically balanced motions and unbalanced internal waves, and thus is an essential indicator of ocean interior dynamics. Using yearlong measurements from a mooring array, we assess the distribution of upper‐ocean steric height across frequencies and spatial scales of O (1–20 km) in the northeast Atlantic. Temporal decomposition indicates that the two largest contributors to steric height variance are large‐scale atmospheric forcing (32.8%) and mesoscale eddies (34.1%), followed by submesoscale motions (15.2%), semidiurnal internal tides (8%), super‐tidal variability (6.1%) and near‐inertial motions (3.8%). Structure function diagnostics further reveal the seasonality and scale dependence of steric height variance. In winter, steric height is dominated by balanced motions across all resolved scales, whereas in summer, unbalanced internal waves become the leading‐order contributor to steric height at scales of O (1 km). |
| format | Article |
| id | doaj-art-6892f09cef384ae38b593fad5a181e1e |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2024-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-6892f09cef384ae38b593fad5a181e1e2025-08-20T02:31:37ZengWileyGeophysical Research Letters0094-82761944-80072024-03-01516n/an/a10.1029/2023GL106480Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude OceanXiujie Zhang0Xiaolong Yu1Aurélien L. Ponte2Wenping Gong3School of Marine Sciences Sun Yat‐sen University Zhuhai ChinaSchool of Marine Sciences Sun Yat‐sen University Zhuhai ChinaIfremer Université de Brest CNRS IRD Laboratoire D’Océanographie Physique et Spatiale IUEM Brest FranceSchool of Marine Sciences Sun Yat‐sen University Zhuhai ChinaAbstract The baroclinic component of the sea surface height, referred to as steric height, is governed by geostrophically balanced motions and unbalanced internal waves, and thus is an essential indicator of ocean interior dynamics. Using yearlong measurements from a mooring array, we assess the distribution of upper‐ocean steric height across frequencies and spatial scales of O (1–20 km) in the northeast Atlantic. Temporal decomposition indicates that the two largest contributors to steric height variance are large‐scale atmospheric forcing (32.8%) and mesoscale eddies (34.1%), followed by submesoscale motions (15.2%), semidiurnal internal tides (8%), super‐tidal variability (6.1%) and near‐inertial motions (3.8%). Structure function diagnostics further reveal the seasonality and scale dependence of steric height variance. In winter, steric height is dominated by balanced motions across all resolved scales, whereas in summer, unbalanced internal waves become the leading‐order contributor to steric height at scales of O (1 km).https://doi.org/10.1029/2023GL106480steric heightsubmesoscale motionsinternal wavesSWOT |
| spellingShingle | Xiujie Zhang Xiaolong Yu Aurélien L. Ponte Wenping Gong Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean Geophysical Research Letters steric height submesoscale motions internal waves SWOT |
| title | Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean |
| title_full | Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean |
| title_fullStr | Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean |
| title_full_unstemmed | Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean |
| title_short | Effects of Balanced Motions and Unbalanced Internal Waves on Steric Height in the Mid‐Latitude Ocean |
| title_sort | effects of balanced motions and unbalanced internal waves on steric height in the mid latitude ocean |
| topic | steric height submesoscale motions internal waves SWOT |
| url | https://doi.org/10.1029/2023GL106480 |
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