Decay mechanism of the 2004/05 Kuroshio large meander revealed by MOVE/MRI.COM
Abstract
The mechanism governing the decay process of the 2004/05 Kuroshio large meander that occurred in the summer of 2004 and decayed in the next summer is studied using an eddy resolving ocean data assimilation and prediction system (MOVE/MRI.COM). The assimilated results suggest that a minor path transition occurred on the Izu Ridge in January 2005 and it trigged the subsequent large meander decay. The trough of the large meander shifts eastward toward the Izu Ridge in association with the path transition, and the eastern part of the meander rides on the Izu Ridge. As a result, the Kuroshio path on the Izu Ridge moves southward from 34N to around 32N. This path transition is caused by a disturbance propagating along the Kuroshio, which is generated by an interaction between an anticyclonic eddy and the Kuroshio east of the Tokara Strait. In addition, the intensity of the cold-core eddy associated with the large meander starts to weaken after this path transition. On the other hand, tide gauge data shows that sea level at the southern coast of Japan significantly decreases after January 2005. A sensitivity analysis suggests that a coastal trapped wave excited as a result of the path transition on the Izu Ridge brings about the sea level decrease. In June 2005, the second minor path transition occurred on the Izu Ridge. It is also caused by a disturbance coming from the upstream of the Kuroshio. Then the Kuroshio path straddles the Izu Ridge. After that, the amplitude of the meander rapidly decreases and the large meander disappears.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMOS52A..06U
- Keywords:
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- 4260 OCEANOGRAPHY: GENERAL / Ocean data assimilation and reanalysis;
- 4263 OCEANOGRAPHY: GENERAL / Ocean predictability and prediction;
- 4576 OCEANOGRAPHY: PHYSICAL / Western boundary currents