SIO Faculty Candidate Seminar - John Colosi

10/12/2017 - 4:00pm

DATE:          October 12th, Thursday, 4pm  
            (Additionally, a chalk talk will be held on 10/13 at 2pm in NH101) 

LOCATION:     Spiess Hall 330
SPEAKER:      John Colosi, Ph.D.
            Naval Postgraduate School
TITLE:          A Scintillating Problem:  Sound Propagation through the Stochastic Ocean


Not long after the 1944 discovery of the ocean sound channel by Ewing and Worzel it became quite evident that this was a fluctuating channel giving rise to frequent transmission fade outs and rapid phase jumps that complicate practical applications. In a 1950 National Research Council report Eckart and Carhart state, that if sound is transmitted through the sea, 

``… the intensity of the signal received from one second to the next will not be constant; it fluctuates often by a factor of 10. Indeed the presence of fluctuations is perhaps the most constant characteristic of sound in the sea’’ 

This talk will review the present state of our understanding of the nearly 70 year old subject of sound propagation though the stochastic ocean, where key contributions have come from (1) developments in physical oceanography such as the Garrett-Munk internal wave spectrum and spicy sound speed structure, (2) technological advances in source and receiver capability,  (3) advances in computing and data processing power, and (4) developments in theoretical physics such as Feynman path integrals, transport theory, and dynamical systems theory. New challenges exist aplenty including gaining an understanding of arctic and high latitudes, the mixed layer and upper ocean, and monitoring various aspects of climate change. For progress, significant contributions from all four of the aforementioned fields will be required. 


Faculty Host:  John Hildebrand (
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Spiess Hall 330