Publication Date:
2022-05-25
Description:
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Dynamics of Atmospheres and Oceans 43 (2007): 123-150, doi:10.1016/j.dynatmoce.2006.08.001.
Description:
This study examines mid-latitude climate variability in a model that couples turbulent
oceanic and atmospheric flows through an active oceanic mixed layer. Intrinsic
ocean dynamics of the inertial recirculation regions combines with nonlinear atmospheric
sensitivity to sea-surface temperature (SST) anomalies to play a dominant
role in the variability of the coupled system.
Intrinsic low-frequency variability arises in the model atmosphere; when run in
a stand-alone mode, it is characterized by irregular transitions between preferred
high-latitude and less frequent low-latitude zonal-flow states. When the atmosphere
is coupled to the ocean, the low-latitude state occurrences exhibit a statistically
significant signal in a broad 5–15-year band. A similar signal is found in the time
series of the model ocean’s energy in this coupled simulation. Accompanying uncoupled
ocean-only and atmosphere-only integrations are characterized by a decrease
in the decadal-band variability, relative to the coupled integration; their spectra are
indistinguishable from a red spectrum.
The time scale of the coupled interdecadal oscillation is set by the nonlinear adjustment
of the ocean’s inertial recirculations to the high-latitude and low-latitude
atmospheric forcing regimes. This adjustment involves, in turn, SST changes resulting
in long-term ocean–atmosphere heat-flux anomalies that induce the atmospheric
regime transitions.
Description:
This research
was supported by NSF grant OCE-02-221066 (all co-authors) and DOE grant
DE-FG-03-01ER63260 (MG and SK).
Keywords:
Inertial recirculations
;
Mid-latitude jet stream
;
Bimodality
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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