Connection between various small‐waveheight solutions of the problem of scattering from the ocean surface.pdf

Connection between various small-waveheight solutions of the problemof scatteringfrom the ocean surface F. M. Labianca and E. Y. Harper Bell Laboratories,Whippany,NewJersey07981 (Received10 March 1977) Carefuldevelopmentsof a numberof approximatesolutionsof the problemof pointsourceacoustic scatteringfromtheoceansurfacearepresented.Theregimeof interestisthesmall-waveheightregime, wherethe rmswaveheightof the oceansurfaceis smallcomparedto theacousticwavelengthandthe correlationlengthoftheoceansurface.Theapproximatesolutionsfall intotwocategories:thosederived byutilizingtheKirchhoffapproximationandthosebasedona small-waveheightperturbationexpansion.It is shownthat withinthe small-waveheightregimethe small-perturbationsolutionis superiorto any solutionbasedonthe Kirchhoffapproximation,theformerbeinguniformlyvalidin theratioof acoustic wavelengthtosurface-wavewavelength.In thatportionofthesmall-waveheightregimewheretheratioof acousticwavelengthto surface-wavewavelengthissmall,all approximatesolutionsareshownto bein agreement.PitfallswhichcanandhaveoccurredinthemisapplicationoftheKirchhoffapproximationare pointed out. • PACS numbers: 43.30.Gv, 43.20.Fn, 43.30.Bp INTRODUCTION AND SUMMARY In order to discussthe connectionbetweenthe Various approximations cited abovewe define the characteristic In this paper we consider the problem of soundgener- lengths of the problem: ated at frequency to by a point source in an oceanof con- stant soundspeed c and scattered by