Preface
As a moderator and initiator of climate variability and change, and as an economic resource, the
global ocean is vital to life on earth. Quantifying the ocean’s role in climate has become a matter
of urgency as society attempts to gauge how growing greenhouse gas concentrations will affect
climate. The intergovernmental agreements of the Kyoto Protocol of 1997 indicate that policymakers are aware of the need to act on the basis of climate projections reported by the Intergovernmental Panel on Climate Change. Determining how to improve, extend and use these
projections is an enormous challenge.
The World Ocean Circulation Experiment (WOCE) is at the heart of this challenge. It predates
the World Climate Research Programme, of which it is now a part. WOCE was the brainchild of a
small group of scientists who, in the early 1980s, saw the prospects for instituting the first truly
global ocean study, using new satellite technology and global ocean models made possible by
increasing computer power. WOCE also needed unstinting international collaboration to collect
a previously unobtainable in-situ global data set for validating and improving ocean circulation
models. The satellite remote sensing, navigation and computer advances in the 1990s, coupled
with developing electronic communication and the World Wide Web, made such an enterprise
possible. In the process, WOCE revolutionized oceanography.
From 1990, ship-based physical and chemical measurements and satellite remote sensing
together resulted in a data set of unprecedented scope and precision. New observational techniques were also developed, maturing to form the basis of an operational observing system
(Argo) for the interior of the global ocean. WOCE has resulted in a much closer interaction of
observers and modellers. It also gave us the first generation of global data-assimilating models,
which are immensely more powerful than the techniques previously available. The new data set
and techniques are a key ingredient in decadal climate prediction and the results of WOCE have
reinforced the evidence that the ocean plays a key role in the earth’s climate.
Ocean Circulation and Climate – Observing and Modelling the Global Ocean presents the
state of knowledge of the ocean and its role in climate change at the end of the twentieth century. The idea for the book originated from the ‘Ocean Circulation and Climate’ conference held
in Halifax, Canada, in 1998. The conference marked the end of the observational phase of
WOCE and the beginning of the Analysis, Interpretation, Modelling and Synthesis (AIMS) phase
that is tackling many aspects of the ocean’s role in climate. After the conference, we approached
the plenary speakers and other distinguished scientists to contribute to this book. We were
delighted that so many agreed to join us in this project.
The book chapters draw mainly from recent WOCE results, and naturally the contributors
identify a number of outstanding questions and uncertainties. However, this book is not a final
summary of WOCE’s achievements; WOCE researchers continue to publish a steady stream of
new results in the refereed literature. Many of these results are based on the exploitation and
synthesis of the unique WOCE basin- and global-scale observations and on the latest generation
of ocean and climate models.
The Ocean and Climate (Section 1) discusses the importance of the ocean in the climate system, describes the main ocean processes and reviews the history of WOCE. In Observations and
Models (Section 2) some fundamental aspects of ocean observations and models are discussed.
New Ways in Observing the Ocean (Section 3) introduces the new observational methods
and instruments and the challenge of data and information management. The Global Flow Field
(Section 4) discusses the state of knowledge of the global oceanic circulation from the surface to
the deep ocean and from the Arctic to the tropical and Antarctic regions, as well as interocean
As a moderator and initiator of climate variability and change, and as an economic resource, the
global ocean is vital to life on earth. Quantifying the ocean’s role in climate has become a matter
of urgency as society attempts to gauge how growing greenhouse gas concentrations will affect
climate. The intergovernmental agreements of the Kyoto Protocol of 1997 indicate that policymakers are aware of the need to act on the basis of climate projections reported by the Intergovernmental Panel on Climate Change. Determining how to improve, extend and use these
projections is an enormous challenge.
The World Ocean Circulation Experiment (WOCE) is at the heart of this challenge. It predates
the World Climate Research Programme, of which it is now a part. WOCE was the brainchild of a
small group of scientists who, in the early 1980s, saw the prospects for instituting the first truly
global ocean study, using new satellite technology and global ocean models made possible by
increasing computer power. WOCE also needed unstinting international collaboration to collect
a previously unobtainable in-situ global data set for validating and improving ocean circulation
models. The satellite remote sensing, navigation and computer advances in the 1990s, coupled
with developing electronic communication and the World Wide Web, made such an enterprise
possible. In the process, WOCE revolutionized oceanography.
From 1990, ship-based physical and chemical measurements and satellite remote sensing
together resulted in a data set of unprecedented scope and precision. New observational techniques were also developed, maturing to form the basis of an operational observing system
(Argo) for the interior of the global ocean. WOCE has resulted in a much closer interaction of
observers and modellers. It also gave us the first generation of global data-assimilating models,
which are immensely more powerful than the techniques previously available. The new data set
and techniques are a key ingredient in decadal climate prediction and the results of WOCE have
reinforced the evidence that the ocean plays a key role in the earth’s climate.
Ocean Circulation and Climate – Observing and Modelling the Global Ocean presents the
state of knowledge of the ocean and its role in climate change at the end of the twentieth century. The idea for the book originated from the ‘Ocean Circulation and Climate’ conference held
in Halifax, Canada, in 1998. The conference marked the end of the observational phase of
WOCE and the beginning of the Analysis, Interpretation, Modelling and Synthesis (AIMS) phase
that is tackling many aspects of the ocean’s role in climate. After the conference, we approached
the plenary speakers and other distinguished scientists to contribute to this book. We were
delighted that so many agreed to join us in this project.
The book chapters draw mainly from recent WOCE results, and naturally the contributors
identify a number of outstanding questions and uncertainties. However, this book is not a final
summary of WOCE’s achievements; WOCE researchers continue to publish a steady stream of
new results in the refereed literature. Many of these results are based on the exploitation and
synthesis of the unique WOCE basin- and global-scale observations and on the latest generation
of ocean and climate models.
The Ocean and Climate (Section 1) discusses the importance of the ocean in the climate system, describes the main ocean processes and reviews the history of WOCE. In Observations and
Models (Section 2) some fundamental aspects of ocean observations and models are discussed.
New Ways in Observing the Ocean (Section 3) introduces the new observational methods
and instruments and the challenge of data and information management. The Global Flow Field
(Section 4) discusses the state of knowledge of the global oceanic circulation from the surface to
the deep ocean and from the Arctic to the tropical and Antarctic regions, as well as interocean