6.1.8 Outlook for direct estimates of
ocean heat transport
Analysis of WOCE measurements for ocean circulation and heat transport has taken two primary
paths to date: careful analysis of individual sections and large-scale inverse analyses using many
sections. Analysis of individual sections has been
hampered by some data sets not yet being available for general analysis, either because they have
not been finally processed or because they have
not been made publicly available. The successful
synthesis of the Pacific 32°S section, where for the
first time subsurface float trajectories could be
included in the analysis, suggests that ocean circulation and heat transport across each of the
WOCE sections will have a much firmer basis
when all measurements made along the section
during WOCE (including hydrographic, tracer,
ADCP and LADCP (Lowered ADCP), subsurface
and surface float, altimetric, and moored current
meter measurements) can be considered in the
analysis. Large-scale inverse analyses have generally combined many WOCE sections and made
reasonable, but not carefully determined, choices
for the initial reference level, with the idea that the
inverse solution would iron out the conflicting
parts of the initial circulation. As a result, the
inverse solutions can be criticised as unrealistic in
some way by scientists who have worked on one
piece of the problem. An additional issue is a lack
of understanding of how far a poor choice of initial reference level will spread inaccuracies in the
final inverse solution. Can the inverse solution
with enough data and constraints fix any initial
problems? Or will an inverse solution always
spread any initial problems throughout the final
solution? Ultimately the goal should be to combine
the results from carefully analysed individual sections into a large-scale inverse model, which
would start from an initial circulation with minimal problems and whose solution would ensure
that the overall circulation is consistent for all the
considered sections. Only at that point would
the ocean circulation necessary for determining the
ocean heat transport be well defined.
SECTION 6 LARGE-SCALE OCEAN TRANSPORTS
474
ocean heat transport
Analysis of WOCE measurements for ocean circulation and heat transport has taken two primary
paths to date: careful analysis of individual sections and large-scale inverse analyses using many
sections. Analysis of individual sections has been
hampered by some data sets not yet being available for general analysis, either because they have
not been finally processed or because they have
not been made publicly available. The successful
synthesis of the Pacific 32°S section, where for the
first time subsurface float trajectories could be
included in the analysis, suggests that ocean circulation and heat transport across each of the
WOCE sections will have a much firmer basis
when all measurements made along the section
during WOCE (including hydrographic, tracer,
ADCP and LADCP (Lowered ADCP), subsurface
and surface float, altimetric, and moored current
meter measurements) can be considered in the
analysis. Large-scale inverse analyses have generally combined many WOCE sections and made
reasonable, but not carefully determined, choices
for the initial reference level, with the idea that the
inverse solution would iron out the conflicting
parts of the initial circulation. As a result, the
inverse solutions can be criticised as unrealistic in
some way by scientists who have worked on one
piece of the problem. An additional issue is a lack
of understanding of how far a poor choice of initial reference level will spread inaccuracies in the
final inverse solution. Can the inverse solution
with enough data and constraints fix any initial
problems? Or will an inverse solution always
spread any initial problems throughout the final
solution? Ultimately the goal should be to combine
the results from carefully analysed individual sections into a large-scale inverse model, which
would start from an initial circulation with minimal problems and whose solution would ensure
that the overall circulation is consistent for all the
considered sections. Only at that point would
the ocean circulation necessary for determining the
ocean heat transport be well defined.
SECTION 6 LARGE-SCALE OCEAN TRANSPORTS
474