Development of a large-aperture coherent hydrophone array, data processing and analysis software system for instantaneous wide-area passive acoustic monitoring of marine mammals

点击翻译按钮获取中文摘要

This project aims to develop and provide high-resolution coherent hydrophone array hardware technology for compliance based marine mammal monitoring in support of seismic survey operations on UNOLs research vessels. A large-aperture densely-sampled hydrophone array system can provide significant enhancement in marine mammal vocalization detection by increasing signal-to-noise ratio via coherent beamforming which eliminates noise outside of the signal beam. Whale vocalizations not detected using a single hydrophone or sparse array can be extracted out of the noise floor by coherent beamforming with the large aperture hydrophone array system. The coherent beamforming also provides high-resolution estimates of whale vocalization bearings which are required for finding the range of the whale from the array and localizing the marine mammal in geographic space. In addition to the array hardware, the project also aims to develop a real-time array signal data acquisition, processing and analysis software to provide real-time detection, bearing-estimation, localization and tracking, and classification of marine mammal vocalizations received on the coherent hydrophone array hardware system. The hardware and software systems together make up the passive ocean acoustic waveguide remote sensing (POAWRS) technology.POAWRS is a transformative approach for ocean sensing, since it is capable of monitoring sound sources over instantaneous wide areas spanning 100 km or more in diameter. In addition to marine mammal vocalizations, the other sound sources detected by POAWRS include biology such as sounds from fish and crustaceans; geophysical processes such as hurricanes and submarine volcanoes; and man-made activities such as ships and other ocean vehicles, seismic airgun and sparker for earthquake plate tectonic studies and oil exploration, as well as offshore piling. The instantaneous continental-shelf scale environmental monitoring capability and temporal-spatial dynamics of sound sources revealed by POAWRS makes it an important technology that could become an indispensable tool in field operations, such as large-scale marine ecological studies, fisheries stock assessments and management, compliance-based marine mammal monitoring mandated by the Marine Mammal Protection Act in seismic surveys and naval sonar surveillance operations, as well as in studies of the effects of man-made sound on marine ecosystems. When combined with an active acoustic or seismic source, such as on the RV Langseth, the proposed instrumentation can be extended for large-scale imaging of objects and features in geophysical, fisheries, ecological and archeological surveys. The project provides an opportunity for training and development work to a diverse team that includes both women and under-represented minorities. The principal investigator has and will continue to host and provide opportunities for K-12 students, undergraduates and teachers to learn and contribute to ocean exploration and discovery through Northeastern University's STEM Education Center, Research Experience for Teachers (RET), Young Scholars Program (YSP) and various undergraduate research opportunity programs. They have and will continue to visit elementary, middle and high schools to provide demonstrations and hands-on training in ocean discovery and sensing through ocean sounds.