7.1.1 Exploiting the WOCE data set
The primary goal of WOCE is to obtain an understanding of the large-scale circulation of the world
ocean, its time variability, and its impact on climate. This knowledge is necessary in its own right
and will also help to improve coupled models for
climate diagnosis and prediction. A global WOCE
survey of the circulation has been completed.
Analysis of these data sets is now proceeding, as are
improvements in ocean general circulation models
and developments in constraining models by the
observations. The thrust of these efforts, current
progress and future plans are described briefly in
this chapter. The WOCE bibliography, maintained
by the WOCE International Project Office, already
numbers more than 1200 refereed articles at the
end of 2000, many of which contribute significantly to understanding regional oceanography.
Description and understanding of the oceans at
basin and global scales is being addressed during
the WOCE Analysis, Interpretation, Modelling
and Synthesis (AIMS) phase, as discussed extensively in various chapters of this book. Central
issues include the ventilation and the renewal rates
of water masses, the determination of oceanic
transport of heat, fresh water and tracers, their
divergences, and a description of ocean variability
during the WOCE period. These activities build on
the existence of and widespread access to the comprehensive and pre-assembled WOCE data set, as
well as continued development of ocean general
circulation models with ever-more sophisticated
algorithms and enhanced resolution, and development of data assimilation methods. A number of
regional process experiments were undertaken as
part of WOCE to address specific scientific questions such as the detailed mechanisms of ventilation
through subduction and convection, thermocline
and abyssal mixing rates, and abyssal upwelling
quantification and processes.
From global WOCE (including altimetry) and
pre-WOCE data sets (e.g. existing long oceanographic time series) and through improved modelling capabilities, it is evident that the ocean has
vigorous variability on all time and space scales.
Increasing emphasis is being put therefore on the
changing ocean state and its relation to changing
atmospheric forcing conditions at time scales of
intraseasonal to decadal. In order to proceed
towards understanding this variability, a requirement of the WOCE synthesis phase is to provide
the best possible description of the time-evolving
ocean state during the WOCE period. WOCE syntheses therefore merge information from various
WOCE data sets to enhance our understanding of
the ocean circulation in a way that is more complete than can be done from one data set or model
alone. Three associated and overlapping activities
are central to synthesis activities: (1) analysis,
which includes the assembly and synthesis of data
with ocean models, which can be as simple as
geostrophy; (2) model testing and improvements,
which include comparison of model results with
the WOCE data set and the estimate of formal
model error descriptions as input for, e.g. ocean
state estimation; and (3) ocean state estimation
(assimilation), by which ocean circulation models
are combined with WOCE and other data sets.
7.1
Towards a WOCE Synthesis
Lynne D.Talley, Detlef Stammer and Ichiro Fukumori
525
OCEAN CIRCULATION AND CLIMATE
Copyright © 2001 Academic Press
ISBN 0-12-641351-7
All rights of reproduction in any form reserved
CHAPTER
The primary goal of WOCE is to obtain an understanding of the large-scale circulation of the world
ocean, its time variability, and its impact on climate. This knowledge is necessary in its own right
and will also help to improve coupled models for
climate diagnosis and prediction. A global WOCE
survey of the circulation has been completed.
Analysis of these data sets is now proceeding, as are
improvements in ocean general circulation models
and developments in constraining models by the
observations. The thrust of these efforts, current
progress and future plans are described briefly in
this chapter. The WOCE bibliography, maintained
by the WOCE International Project Office, already
numbers more than 1200 refereed articles at the
end of 2000, many of which contribute significantly to understanding regional oceanography.
Description and understanding of the oceans at
basin and global scales is being addressed during
the WOCE Analysis, Interpretation, Modelling
and Synthesis (AIMS) phase, as discussed extensively in various chapters of this book. Central
issues include the ventilation and the renewal rates
of water masses, the determination of oceanic
transport of heat, fresh water and tracers, their
divergences, and a description of ocean variability
during the WOCE period. These activities build on
the existence of and widespread access to the comprehensive and pre-assembled WOCE data set, as
well as continued development of ocean general
circulation models with ever-more sophisticated
algorithms and enhanced resolution, and development of data assimilation methods. A number of
regional process experiments were undertaken as
part of WOCE to address specific scientific questions such as the detailed mechanisms of ventilation
through subduction and convection, thermocline
and abyssal mixing rates, and abyssal upwelling
quantification and processes.
From global WOCE (including altimetry) and
pre-WOCE data sets (e.g. existing long oceanographic time series) and through improved modelling capabilities, it is evident that the ocean has
vigorous variability on all time and space scales.
Increasing emphasis is being put therefore on the
changing ocean state and its relation to changing
atmospheric forcing conditions at time scales of
intraseasonal to decadal. In order to proceed
towards understanding this variability, a requirement of the WOCE synthesis phase is to provide
the best possible description of the time-evolving
ocean state during the WOCE period. WOCE syntheses therefore merge information from various
WOCE data sets to enhance our understanding of
the ocean circulation in a way that is more complete than can be done from one data set or model
alone. Three associated and overlapping activities
are central to synthesis activities: (1) analysis,
which includes the assembly and synthesis of data
with ocean models, which can be as simple as
geostrophy; (2) model testing and improvements,
which include comparison of model results with
the WOCE data set and the estimate of formal
model error descriptions as input for, e.g. ocean
state estimation; and (3) ocean state estimation
(assimilation), by which ocean circulation models
are combined with WOCE and other data sets.
7.1
Towards a WOCE Synthesis
Lynne D.Talley, Detlef Stammer and Ichiro Fukumori
525
OCEAN CIRCULATION AND CLIMATE
Copyright © 2001 Academic Press
ISBN 0-12-641351-7
All rights of reproduction in any form reserved
CHAPTER