124
Walter Munk
Figure 8.3. The first reciprocal transmission experiment was conducted by Worcester in 1976 off San
Diego. 10 Top: The two ray paths for the 25-km range. Bottom: Intensity as a function of source time
τ for transmissions at clock time t. Each transmission shows an early (deep) arrival in about 17.50
seconds followed by a late (shallow) arrival in 17.54 seconds. Successive transmissions during the
25-minute experiment show a complex and variable pattern for the upper path. Reciprocal transmissions (not shown) gave information about shallow and deep currents.
Carl Wunsch and I summarized the application of acoustic inverse techniques to
monitoring an ocean basin for mesoscale fluctuations.
12 We concluded that such a system was achievable NOW. We chose the obscure name “ocean acoustic tomography”
(in analogy with medical tomography for probing the interior of a brain by waves
propagating through the brain in many directions) in the hope that our colleagues
would want to find out what it was all about. The early emphasis was to produce contour charts with mesoscale resolution. The procedure going from transmission plots
to the contour charts relies heavily on the application of inverse methods. There were
(and still are) many loose ends; Carl and I spent a sabbatical year at the University
of Cambridge to follow up some of the open topics.
13 Carl attended a Royal Society
Walter Munk
Figure 8.3. The first reciprocal transmission experiment was conducted by Worcester in 1976 off San
Diego. 10 Top: The two ray paths for the 25-km range. Bottom: Intensity as a function of source time
τ for transmissions at clock time t. Each transmission shows an early (deep) arrival in about 17.50
seconds followed by a late (shallow) arrival in 17.54 seconds. Successive transmissions during the
25-minute experiment show a complex and variable pattern for the upper path. Reciprocal transmissions (not shown) gave information about shallow and deep currents.
Carl Wunsch and I summarized the application of acoustic inverse techniques to
monitoring an ocean basin for mesoscale fluctuations.
12 We concluded that such a system was achievable NOW. We chose the obscure name “ocean acoustic tomography”
(in analogy with medical tomography for probing the interior of a brain by waves
propagating through the brain in many directions) in the hope that our colleagues
would want to find out what it was all about. The early emphasis was to produce contour charts with mesoscale resolution. The procedure going from transmission plots
to the contour charts relies heavily on the application of inverse methods. There were
(and still are) many loose ends; Carl and I spent a sabbatical year at the University
of Cambridge to follow up some of the open topics.
13 Carl attended a Royal Society