Mapping and Characterizing Mixing Processes in the Ocean Using Broadband Acoustic Techniques

Elizabeth Weidner
Ph.D. Thesis Proposal Defense


Friday, Dec. 18, 2020, 9:00am

In the ocean, mixing between fluid bodies is both ubiquitous and highly variable, and facilitates the transport of nutrients, heat, oxygen, pollutants, and many other constituents throughout the ocean. Fluid emissions into ocean waters produce up-welling currents from buoyancy effects, and detection of these emissions and their associated energetics can facilitate the identification of processes associated with erosional events on the seafloor. Although hugely important to oceanography, mixing phenomenon can be difficult to observe and characterize due to the broad spatial scales of the ocean, the ephemeral nature of the imprint of mixing dynamics between bodies of water, and the remote locale of many of these processes. Active acoustic systems offer the opportunity for non-intrusive, synoptic observations of mixing dynamics in the water column, allowing for continuous, high resolution data collection over a broad spatial scale. This research will utilize broadband systems to distinguish scattering from oceanic fluid mixing from other phenomena, characterize the broadband acoustic spectra of these flows, and work towards acoustic inversion techniques to estimate mixing rates and other parameters, such as heat flux. This work will include ocean mixing processes involving fluids with both temperature and salinity differences in a range of environments and energetics.


Elizabeth Weidner graduated from the University of Washington in 2012 with a B.S. in Oceanography. Before coming to CCOM/JHC, she worked as a geophysicist for C&C Technologies. In May of 2018, she received her Master's in Earth Science: Ocean Mapping from the University of New Hampshire with thesis titled: "A wideband acoustic method for direct assessment of bubble-mediated methane flux." She is currently pursuing a Ph.D. in Oceanography in a joint program between the University of New Hampshire and Stockholm University. Her research is focused on the broadband acoustic discrimination and characterization of ocean watercolumn structures.