Spin-up of Southern Hemisphere Super Gyre
Abstract
This study investigates the variability of Southern Hemisphere Super Gyre, using remotely sensed altimeter measurements, in-situ observations, and results from an ocean general circulation model. The analyses of altimeter data show isolated trends of increasing sea surface height in all the three southern subtropical oceans since 1993. These increasing trends reflect dynamic signals extending from the sea surface to at least 2000 m, which suggests a strengthening of the three southern subtropical gyres. The three southern subtropical gyres are inter-connected through the Tasman and Agulhas Leakages, and vary rather consistently during the period 1993-2016. The Tasman and Agulhas Leakages also show an increasing trend of inter-ocean water exchange with a typical increase of 2 Sv per decade, indicative of a two-decade-long spin-up of the Southern Hemisphere Super-Gyre. The strengthening of the westerly winds and their poleward shift associated with an increasing Southern Annular Mode directly affect the mid- and high-latitude southern hemisphere oceans and contribute to the spin-up of the Southern Hemisphere Super-Gyre.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS31H1888Q
- Keywords:
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- 4207 Arctic and Antarctic oceanography;
- OCEANOGRAPHY: GENERALDE: 4255 Numerical modeling;
- OCEANOGRAPHY: GENERALDE: 4260 Ocean data assimilation and reanalysis;
- OCEANOGRAPHY: GENERALDE: 4262 Ocean observing systems;
- OCEANOGRAPHY: GENERAL