Abstract
As abyssal ocean properties are altered by climate change, density
stratification may be expected to change in response. This shift can
affect the buoyancy flux, internal wave generation, and turbulent
dissipation, which may impact mixing and vertical transport. In this
study, repeated surveys of three hydrographic sections in the Southwest
Pacific Basin between the 1990s-2010s are used to estimate the change in
buoyancy frequency N. We find that below Θ = 0.8◦C, N is reduced by a
mean scaling factor of 0.88{plus minus}0.06 per decade. This reduction
is intensified at depth, with the biggest change observed at Θ=0.63◦C by
a scaling factor of 0.71{plus minus}0.07. Within the same time period,
the magnitude of per unit area vertical diffusive heat flux is reduced
by about 0.01 Wm, although this estimate is sensitive to the choice of
estimated diffusivity. Finally, implications on heat budget and global
ocean circulation are qualitatively discussed.