Journal of Geophysical Research: Oceans:Vol. 105, No. C7, pp.16,823-16,842
Processes that influence sea surface temperature and ocean mixed layer depth variability in a coupled model
Michael A. Alexander and James D. Scott
NOAA-CIRES/Climate Diagnostics Center, University of Colorado, Boulder, Colorado
Clara Deser
National Center for Atmospheric Research, Boulder, Colorado
(Submitted 30 March 1999, Resubmitted 2 February 2000, Accepted 5 April 2000)
A 50-year coupled atmosphere-ocean model integration is used to study sea surface temperature (SST)
and mixed layer depth (h), and the processes which influence them. The model consists of an atmospheric
general circulation model coupled to an ocean mixed layer model in ice-free regions. The midlatitude SST
variability is simulated fairly well, although the maximum variance is underestimated and located farther
south than observed. The model is clearly deficient in the vicinity of the Gulf Stream and in the eastern
tropical Pacific where advective processes are important. The model generally reproduces the observed
structure of the mean h in both March and September but underestimates it in the North Atlantic during
winter. The net surface heat flux strongly regulates both the mean ( )and anomalous ( ' ) SSTs throughout
the year. The entrainment heat flux, which is proportional to the product of the entrainment rate and the
temperature jump at the base of the mixed layer , influences SSTs in summer and fall, especially north of
~35°N (45°N) in the Pacific (Atlantic). is more important for the development of in fall compared to ,
which is larger in summer. Anomalies in h have a significant impact on the heat balance of the mixed
layer during spring and summer. The entrainment rate is dominated by wind-induced mixing in summer and
surface buoyancy forcing in winter; the density jump at the base of the mixed layer is of secondary
importance.
Note: This abstract is courtesy of the American Geophysical Union (AGU), who owns sole rights to it. The
abstract is subject to AGU copyright laws and statutes. For more information, please visit the AGU website
at http://www.agu.org.
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Hongjun Zhang:
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