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ocean acoustics
MS Plan A Defense: Reliable Acoustic Path Tomography at the ALOHA Cabled Observatory: Continuing studies
Holmes Hall 243 2540 Dole Street, Honolulu, HI, United StatesSitthichat (Boris) Sukpholtham We have investigated the feasibility of Reliable Acoustic Path (RAP) tomography using a mobile ship platform (R/V Kilo Moana) and the existing acoustic infrastructure at the ALOHA Cabled Observatory (ACO). Travel times of acoustic signals traveling along direct paths between the shipboard acoustic source and the bottom-mounted hydrophones were measured. Perturbations of the travel times relative to predicted travel times were obtained, based on the CTD cast closest in time to the experiment date. Stochastic linear inversion was employed to solve for the sound speed perturbation field using the travel time perturbation measurements. This provides a spatially-dependent
Seminar: Acoustics: From Cavitation to Detection in Clutter
Sakamaki B101 2530 Dole St, Honolulu, HI, United StatesJohn Allen, PhD Associate Professor Department of Mechanical Engineering University of Hawai’i, Mānoa Bubble dynamics and cavitation have had prominent roles in acoustics since Lord Rayleigh's pioneering work noise from ship propellers. Ocean applications are highlighted with respect to ambient noise produced from snapping shrimp off the coast of Hawaii. Snapping shrimp produce sounds by closing an enlarged claw rapidly, creating a cavitation bubble with a water jet. Snapping shrimp sound production has not been previously measured in natural environments with recording levels commensurate with the transient nature of the cavitation bubble sound. Previous field studies have investigated time averaged
Seminar: Acoustic signal processing for tracking marine mammals
Biomed T 211 1960 East-West Road, Honolulu, HI, United StatesPina Gruden, PhD Post-Doctoral Researcher Joint Institute for Marine and Atmospheric Research Acoustics provides a useful tool to study various aspects of marine mammal biology, such as species identification, behaviour, habitat use, and abundance estimation. In order to answer these questions the acoustic information needs to be first extracted and processed from underwater recordings. This is a challenging task due to large volumes of data, noise and interfering signals present in the recordings. Moreover, multiple animals often vocalize at once, and their sounds are very diverse, further complicating the extraction and processing problem. This seminar will focus on a tracking
Seminar: ORE Student Presentations
Andi Erickson, Nicholas Ulm, Giannicola Tumino Di Costanzo, Julianne Kalksma, Shijie Huang, Kei Manabe, Cameron Morrow, David Leyva, Stefan Mrozewski Nine ORE graduate students will present as part of our new ORE seminar session “Improving effective communication skills”. Each student will present their research work or interest in about 3 minutes to a targeted audience. Topics include: El Niño southern oscillation, powering blue economy, ultra-short base line, photography for coastal research, multi-flow simulation, detecting spinner dolphin clicks, analysis of mooring line fatigue, choosing appropriate buoys for long-term time-series analysis, and factors affecting underwater laser Transmission. The targeted audience ranges from
Seminar: Improving Odontocete Acoustic Tracking Performance Using More Informative Measures
Zoom Meeting ID______ 935 9608 7383 Passcode: OREseminarPina Gruden, PhD Postdoctoral Acoustic Researcher Joint Institute for Marine and Atmospheric Research, UH Mānoa Passive acoustic monitoring (PAM) is a frequently used tool for various aspects of marine mammal research, including identifying species, their abundance and behavior. Traditionally, boat-based visual line-transect surveys are carried out with the goal of estimating species abundance. PAM is an important addition to visual surveys, especially for elusive species (in which groups are frequently missed by visual observers), species with complex group structure, and species that show behavioral response to boat presence. This seminar will discuss the challenging problem of tracking multiple false
Seminar: Moving Ship Tomography and Passive Processing Approaches to Characterize Environmental Parameters
https://hawaii.zoom.us/j/93596087383Dr. Kay L. Gemba Associate Professor of Physics Naval Postgraduate School Zoom Meeting Link: Meeting ID: 935 9608 7383 Passcode: OREseminar https://hawaii.zoom.us/j/93596087383 Passive processing approaches provide utility to characterize acoustically relevant parameters to improve environmental awareness. Of particular interest are transiting surface vessels due to their high acoustic intensity and wide-band energy. To understand quantitatively the value-added of moving ship observations, a controlled experiment was conducted in the Santa Barbara Channel in 2016. These data are used in a data-assimilation approach, initialized with an oceanographic circulation model. The estimated vertical sound-speed structure compares well with ground-truth observations. Current work focuses
Seminar: Sounds, Signals, Spectra: Splash to Buzz
Holmes 247 2540 Dole Street, Honolulu, HI, United StatesDr. John S. Allen Associate Professor Department of Mechanical Engineering University of Hawai‘i at Mānoa Location Information: **this seminar will be held both in person (Holmes Hall 247) and over Zoom** Meeting ID: 960 4654 5799 Passcode: OREseminar https://hawaii.zoom.us/j/96046545799 Acoustics is an extensive inter-disciplinary research area that encompasses topics in diverse fields such as music, science and engineering. The areas of acoustic share a common core with respect to the governing equations for wave propagation in gaseous (air), liquid (water) or solid materials. Bubbles play an important role in sound generation in the ocean as well physical and biomedical acoustic
Advancements in passive acoustic monitoring: A framework for automated tracking of marine mammals
Watanabe 112 2505 Correa Rd, Honolulu, HI, United StatesDr. Pina Gruden Acoustics Researcher Cooperative Institute for Marine and Atmospheric Research and Department of Ocean Resources Engineering University of Hawaiʻi at Mānoa Location Information **This seminar will be held both in person (Watanabe Hall 112) and over Zoom** Meeting ID: 961 6222 2366 Passcode: OREseminar https://hawaii.zoom.us/j/96162222366 Passive acoustic monitoring (PAM) is an efficient tool for studying acoustically active sources such as marine mammals. Using a variety of sensors and array configurations, PAM can provide insights into species identity, movements, behaviors and abundance of populations, and is thus an invaluable tool for assessing and monitoring populations. With the advancement of
Seminar: Observing the ocean acoustically with the Kauai Beacon source
ORE ZoomKay (Kai) Gemba, Ph.D. Associate Professor, Department of Physics Naval Postgraduate School, Monterey, CA, USA *Zoom only* Meeting ID: 963 5962 3640 Passcode: OREseminar https://hawaii.zoom.us/j/96359623640 The 75 Hz center-frequency Kauai-Beacon Source is well-situated for observing the North Pacific Ocean acoustically, and ongoing efforts enable transmissions and analysis of broadband signals for this 18-month duration time-series. Previously, we demonstrated acoustic receiving along paths to Wake Island (∼3500 km), Monterey Bay, and OOI near Oregon (∼4000 km). Travel time observations to Wake Island compare well with HYCOM reanalysis data in 2023, but the model does not capture a continuous warming trend observed
Seminar: Acoustic inference of sea ice mechanical properties
ORE ZoomD. Benjamin Reeder, Ph.D. Research Professor Department of Oceanography Naval Postgraduate School, Monterey, CA, USA *Zoom only* Meeting ID: 963 5962 3640 Passcode: OREseminar https://hawaii.zoom.us/j/96359623640 Arctic climate is important globally and regionally, in terms of its effects on global temperatures, global sea level, commercial activities and native coastal communities. The Arctic energy budget is driven by atmospheric temperatures, cloud cover, wind patterns, freshwater discharge, oceanic forcing and sea ice cover. Sea ice cover is particularly important because it buffers air-sea heat flux and strongly influences Earth’s absorption of solar radiation through ice-albedo feedback mechanism. Understanding the relative contributions of all
Seminar: Comparing Observations of Seafloor Distributed Fiber-optic Sensing to Observe Ocean Waves
ORE ZoomDr. Hannah Glover Research Associate Oregon State University *Zoom only* Meeting ID: 963 5962 3640 Passcode: OREseminar https://hawaii.zoom.us/j/96359623640 Distributed Acoustic Sensing is emerging as a powerful technique for observing geophysical and oceanographic processes. DAS methods can provide significant improvements in the spatial and temporal density of in-situ data collection. A single instrument attached to a fiber-optic cable, such as a seafloor telecom cable, can continuously record nanoscale cable strain and temperature with meter-scale measurement spacing over 10s of kilometers at kHz frequencies. In this seminar, I will explore recent applications of Distributed Acoustic Sensing (DAS) for quantitatively measuring ocean surface