Shape of storms facilitates energy transfer from weather to deep ocean

Noel Brizuela, Eric D'Asaro, Jennifer MacKinnon

Near inertial internal waves (NIWs) play a key role in transferring energy
from extratropical storms into the ocean interior, where they drive turbulence
that influences large scale circulation and climate. Efficient downward propaga-
tion of NIW energy requires horizontal wavelengths of order 100 km, yet NIWs are
conventionally assumed to be generated with much longer scales near 1000 km,
requiring subsequent modification by ocean vorticity gradients. Here, we refor-
mulate the equations in terms of vorticity and divergence and show that mesoscale
convective systems within storms naturally imprint scales ∼100 km onto the NIW
field, enabling efficient downward energy propagation. Storm morphology may be
an important control on the transfer of energy from the atmosphere to the ocean
interior; its multi-decadal changes may lead to similar changes in mixing at depth.