In
 this and the seven subsequent
 slides,
 one annual cycle of upper
 ocean
 variability is illustrated by
 imaging
 the temperature field
 and
 superimposing the vertical
 coordinate
 interfaces and the
 mixed
 layer base (thick line).
 Differences
 in upper-ocean
 temperature
 can be large at grid
 points
 located in frontal zones and
 the
 boundary regions between
 gyres.
 Horizontal displacement
 of
 these oceanographic features
 among
 simulations can lead to
 substantial
 T differences. In
 general,
 smaller differences are
 observed
 at grid points located
 at
 gyre interiors.
 
 The
 annual cycle at point NAC
 represents
 variability in the
 boundary
 zone between the
 subtropical
 and subpolar gyres.