title: Impact of oceanic-scale interactions on the seasonal modulation of ocean dynamics by the atmosphere.
abstract: Ocean eddies (with a size of 100-300 km), ubiquitous in satellite observations, are known to represent about 80% of the total ocean kinetic energy. Recent studies have pointed out the unexpected role of smaller oceanic structures (with 1-50 km scales) in generating and sustaining these eddies. The interpretation proposed so far invokes the internal instability resulting from the large-scale interaction between upper and interior oceanic layers. Here we show, using a new high-resolution simulation of the realistic North Pacific Ocean, that ocean eddies are instead sustained by a different process that involves small-scale mixed-layer instabilities set up by large-scale atmospheric forcing in winter. This leads to a seasonal evolution of the eddy kinetic energy in a very large part of this ocean, with an amplitude varying by a factor almost equal to 2. Perspectives in terms of the impacts on climate dynamics and future satellite observational systems are briefly discussed.
authors.affiliation: Application Laboratory, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Laboratoire de Physique des Oceans, IFREMER-CNRS-UBO-IRD, Plouzane 29280, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Klein
authors.affiliation: Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Honolulu, Hawaii 96822, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Qiu
authors.affiliation: Research and Development Center for Global Change, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sasai