Publication Date:
2022-05-25
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2008
Description:
A modern general circulation model of the Southern Ocean with one-sixth of a degree
resolution is optimized to the observed ocean in a weighted least squares sense. Convergence
to the state estimate solution is carried out by systematically adjusting the
control variables (atmospheric state and initial conditions) using the adjoint model.
A cost function compares the model state to in situ observations (Argo float profiles,
CTD synoptic sections, SEaOS instrument mounted seal profiles, and XBTs),
altimetric observations (ENVISAT, GEOSAT, Jason, TOPEX/Poseidon), and other
data sets (e.g. infrared and microwave radiometer observed sea surface temperature
and NSIDC sea-ice concentration). Costs attributed to control variable perturbations
ensure a physically realistic solution. The state estimate is found to be largely consistent
with the individual observations, as well as with integrated fluxes inferred from
previous static inverse models.
The transformed Eulerian mean formulation is an elegant way to theorize about
the Southern Ocean. Current researchers utilizing this framework, however, have
been making assumptions that render their theories largely irrelevant to the actual
ocean. It is shown that theories of the overturning circulation must include the effect
of pressure forcing. This is true in the most buoyant waters, where pressure forcing
overcomes eddy and wind forcing to balance a poleward geostrophic transport and
allows the buoyancy budget to be closed. Pressure forcing is also lowest order at depth.
Indeed, the Southern Ocean’s characteristic multiple cell overturning is primarily in
geostrophic balance. Several other aspects of the Southern Ocean circulation are also
investigated in the thesis, including an analysis of the magnitude and variability of
heat, salt, and volume inter-basin transports.
Description:
This work was supported by CalTech - Jet Propulsion Lab contract #1205624
(Global Oceans Dynamics and Transports). Support for my first 2 years in the MITWHOI
Joint Program came from NSF awards #OCE-9901654 (Research in Linear
and Nonlinear Waves and Ocean Circulation Theory). I was also supported for two
months by NSF awards #OCE-0223434.
Keywords:
Ocean circulation
;
Ocean temperature
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
Format:
application/pdf
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