Abstract (150 word limit)
The debate over the historical
and future evolution of the Atlantic Meridional Overturning Circulation
(AMOC) has united scientists around a single topic, but this community
has yet to unite around a single definition of the AMOC. In an effort to
focus the debate around dynamics rather than semantics, we recommend
that the community universally adopt a definition of the AMOC in density
coordinates. We present evidence that the traditional depth space
definition is insufficient at capturing elements of this circulation,
especially at high latitudes where the northward and southward limbs of
the AMOC are separated horizontally rather than vertically. Instead, the
AMOC in density coordinates more realistically captures the water mass
transformation process at high latitudes, shifts the maximum AMOC from
the subtropical to the subpolar North Atlantic where the majority of the
deep waters are formed, and depicts the peak in meridional heat
transport associated with the subtropical gyre.