VI
Preface
In the middle of the past decade Bill Young and I introduced
an advanced graduate course in the MIT /WHOI Joint Program
in Physical Oceanography whose purpose was to introduce our
students to the recent advances in the theory of the ocean
circulation. When Bill left MIT I continued the course, and the
present book has as its basis the material presented in that
course.
Neither that course nor this book are meant to be an exhaustive
review of all aspects of ocean circulation theory. Time, space, and
personal interest lead to a selection of material which is meant to be
fundamental without being encyclopedic. Researchers will note
important subjects not treated. It is, after all, a big field. The
subjects which are treated have been chosen primarily because, in
my view, they offer the best insight into the solid advances recently
made in the field and are likely to remain as building blocks for
future developments.
Chapters 1 and 2 review the simplest ideas of ocean circulation
theory. Chapter 1 describes Sverdrup's theory of horizontal
transport. This theory is still one of the foundations of all theories
of the ocean circulation, and the chapter describes its development
and recent attempts to gauge its validity. In Chapter 2 the theory of
the wind-driven circulation of a fluid of uniform density is taken up.
This is perhaps the most classical of all the problems in physical
oceanography, and it is humbling and exciting to recognize both the
inadequacy of our present understanding and the recently
discovered dynamical complexity of this simplest of all nontrivial
theories for the circulation. The discussion, of interest in itself, is
also designed as a warning concerning the incomplete character of
the theories of the stratified ocean circulation which form the
remainder of the text.
Chapter 3 describes the quasi-geostrophic theory of the winddriven circulation of a stratified ocean. The brilliant theoretical
work of Rhines and Young in the early years of the past decade
revolutionized our understanding of the vertical structure of the
wind-driven circulation. The concepts of geostrophic contours,
potential vorticity homogenization, and their role in shaping the
pattern of the circulation form the core of this chapter.
Chapter 4 takes up the question of understanding the full
density and velocity structure of the wind-driven circulation by
going beyond the quasi-geostrophic theory to consider the
important effect of the ventilation of the thermocline which occurs
as oceanic density surfaces rise to intersect the oceanic mixed layer.
The theory of the ventilated thermocline, on which I have worked
with my colleagues Jim Luyten and Henry Stommel, provides a
mechanism to explain both the vertical and horizontal structures of
Preface
In the middle of the past decade Bill Young and I introduced
an advanced graduate course in the MIT /WHOI Joint Program
in Physical Oceanography whose purpose was to introduce our
students to the recent advances in the theory of the ocean
circulation. When Bill left MIT I continued the course, and the
present book has as its basis the material presented in that
course.
Neither that course nor this book are meant to be an exhaustive
review of all aspects of ocean circulation theory. Time, space, and
personal interest lead to a selection of material which is meant to be
fundamental without being encyclopedic. Researchers will note
important subjects not treated. It is, after all, a big field. The
subjects which are treated have been chosen primarily because, in
my view, they offer the best insight into the solid advances recently
made in the field and are likely to remain as building blocks for
future developments.
Chapters 1 and 2 review the simplest ideas of ocean circulation
theory. Chapter 1 describes Sverdrup's theory of horizontal
transport. This theory is still one of the foundations of all theories
of the ocean circulation, and the chapter describes its development
and recent attempts to gauge its validity. In Chapter 2 the theory of
the wind-driven circulation of a fluid of uniform density is taken up.
This is perhaps the most classical of all the problems in physical
oceanography, and it is humbling and exciting to recognize both the
inadequacy of our present understanding and the recently
discovered dynamical complexity of this simplest of all nontrivial
theories for the circulation. The discussion, of interest in itself, is
also designed as a warning concerning the incomplete character of
the theories of the stratified ocean circulation which form the
remainder of the text.
Chapter 3 describes the quasi-geostrophic theory of the winddriven circulation of a stratified ocean. The brilliant theoretical
work of Rhines and Young in the early years of the past decade
revolutionized our understanding of the vertical structure of the
wind-driven circulation. The concepts of geostrophic contours,
potential vorticity homogenization, and their role in shaping the
pattern of the circulation form the core of this chapter.
Chapter 4 takes up the question of understanding the full
density and velocity structure of the wind-driven circulation by
going beyond the quasi-geostrophic theory to consider the
important effect of the ventilation of the thermocline which occurs
as oceanic density surfaces rise to intersect the oceanic mixed layer.
The theory of the ventilated thermocline, on which I have worked
with my colleagues Jim Luyten and Henry Stommel, provides a
mechanism to explain both the vertical and horizontal structures of