### Acoustical Society of America

Biennial Award - 1982Ralph N. Baer

Ralph N. Baer was born in New York City on 2 January 1948. He attended public City schools, including the selective Bronx High School of Science. Ralph did all of his college work at Rensselaer Polytechnic Institute (RPI), where he specialized in Applied Mathematics and received the B.S., M.S., and Ph.D. degrees in 1968, 1970, and 1974, respectively.
Between 1971 and 1974, Ralph received support for his doctoral studies by serving as a research assistant under an ONR contract in underwater environmental acoustics. Mel Jacobson was Principal Investigator of his contract, and Al Sykes was Scientific Officer for ONR. Ralph's association with the contract resulted in a very interesting Ph.D. thesis, also supervised by Mel Jacobson, as well as four JASA papers concerned with sound transmission through a Rossby wave.
Much of Ralph's work at RPI was highly innovative. In a 1974 JASA paper, he demonstrated his special physical and mathematical abilities by using geophysical fluid dynamics to determine the effects of an assumed Rossby wave on sound speed in the ocean. This work was one of the first "true" environmental-acoustics studies, in the sense that it began with basics, such as fluid dynamics and an equation of state for the ocean. In two subsequent JASA papers, Ralph applied the results of the above investigation to studies of sound propagation through a Rossby state. These papers were novel, too, in the sense that they were the first to couple a true environmental model with ray acoustics. Although these investigations were very complicated, both physically and mathematically, Ralph's unique abilities led him to obtain simple and useful formulas for acoustical effects of such a wave. One of the exciting aspects of this work was that the existence of Rossby waves had been only assumed, and it was not until somewhat later that such waves were actually discovered in the ocean.
After receiving his Ph.D. in 1974, Ralph joined John Munson's Acoustics Division at the Naval Research Laboratory (NRL). Specifically, he worked under Bill Moseley and John DeSanto in the Signal Coherence Section of the Large Aperture Acoustics Branch. In part, Ralph was involved in acoustic propagation in a random ocean, and supervised the implementation of numerical models of theoretical results obtained by John McCoy and Mark Beran. Also, he worked on propagation through fronts and eddies. In the eddy area, he found parabolic equation solutions, in both two and three dimensions, using an approximate eddy model developed by Bob Henrick, Mel Jacobson, and Bill Siegmann at RPI. Among other results, Ralph discovered how the output of a towed array could be used to detect the presence of mesoscale eddies. Ralph made general parabolic equation contributions, as well. For example, he developed an operational code for solving the parabolic equation by means of the split-step technique in three dimensions. This work provided a new capability in the solution of underwater acoustic propagation problems.
In 1980, Ralph was selected as Head of the new Stochastic Propagation Section in Budd Adams' Large Aperture Acoustics Branch within NRL. In his new capacity. Ralph supervises a group of physicists and mathematicians doing theoretical and computational work involving propagation over random bottoms. Also, Ralph interacts with geologists and oceanographers in other NRL Branches, which are responsible for developing ocean bottom environmental models. In addition to his deep involvement in theoretical and numerical activities, Ralph frequently serves as a consultant, in the area of data interpretation, to experimentalists within NRL. Furthermore, Ralph is Scientific Officer for work done for his Section by outside contractors. Another of his duties is to be his Division's representative on a committee which advises the Computer Center on the needs of Laboratory users.
Those of us who have worked closely with Ralph know him to be extremely conscientious. He can be counted upon to have original ideas and to be very thorough and exact in his pursuit of solutions to problems. Indeed, it is because of these qualities that he has been elected to membership in such honorary societies as Sigma Xi and Pi Mu Epsilon. Despite his dedication to technical achievement, however, Ralph has maintained involvement in a number of hobbies, including geneology and bicycling. Early each working day and late on those afternoons, Ralph can be seen riding his bicycle between his Washington apartment and the Naval Research Laboratory.
Ralph N. Baer has co-authored over twenty publications and presentations in underwater acoustics, many of which have been landmark contributions whose novel procedures and results have been utilized by other researchers. His significant accomplishments can be attributed in large part to an uncommon ability to meld physics, mathematics, and computing in a variety of specific underwater acoustics research areas. Because of his impressive history of accomplishment, and because of his special collection of technical interests and abilities, the acoustics community can expect many more useful and exciting contributions from Ralph in the future.
M. J. JACOBSON