A century of sonar performance prediction

Developments in sonar technology went hand in hand with increased scientific understanding of the factors affecting sonar performance The first known reference is from Lichte (Physikalische Zeitschrift 1919) where cylindrical spreading for propagation loss was accounted for in deep water (convergence zone, CZ) propagation. Users of sonar in the 1920s encountered an “afternoon effect”, a temporary dip in performance that occurred during warm summer evenings, was explained in the 1930s by Iselin and Batchelder in terms of vertical temperature gradients in the sea. A significant amount of work occurred in both World War I(Klein 1962, Wood 1965) and World War II to understand, and therefore be able to predict, the capabilities of sonar systems to detect submerged targets. Understanding of sonar performance increased rapidly during WW2 and continued to advance during the Cold War. Advances in the understanding of sonar performance modeling before, during and after the Second World War are described.