Shallow water tomography in a highly variable scenario

摘要: In October 2000, SiPLAB and the Instituto Hidrografico (IH PN) conducted IN TIFANTE’00 sea trial in a shallow area off Peninsula of Troia, approximately 50 km south from Lisbon, Portugal. The experiment itself results obtained most data set have been reported at various occasions last two years. This paper focuses on acquired during Event 2, where acoustic propagation path was range independent source ship held station constant 5.8 vertical line array. Although these conditions were, general, relatively benign for matched-field tomography, retrieval water column bottom parameters over 14-hour-long recording revealed to be extremely difficult. analysis detail characteristics this determines causes observed inversion difficulties. Is is shown that poor performance conventional methods are mainly tide induced spatially correlated noise relative source-receiver motion time averaging. An eigenvalue-based criterion proposed detecting optimal averaging time. It selection procedure together with hydrophone normalization an appropriate objective function provide better model fit consistent thus understanding environmental variability.