Observations and modeling of upper ocean hydrography in the western Arctic with implications for acoustic propagation

Observational and modeling studies are conducted to explore the changing physical environment of the western Arctic Ocean and its significance to upper-ocean hydrography and acoustic energy propagation. In-situ observations of temperature and salinity were made as part of the Canada Basin Acoustic P...

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Bibliographic Details
Main Author: DiMaggio, Dominic F.
Other Authors: Maslowski, Wieslaw, Colosi, John, Oceanography
Format: Thesis
Language:unknown
Published: Monterey, California. Naval Postgraduate School 2016
Subjects:
Online Access:https://hdl.handle.net/10945/51680
Description
Summary:Observational and modeling studies are conducted to explore the changing physical environment of the western Arctic Ocean and its significance to upper-ocean hydrography and acoustic energy propagation. In-situ observations of temperature and salinity were made as part of the Canada Basin Acoustic Propagation Experiment (CANAPE) pilot study in summer 2015. Sound-speed fluctuations due to internal waves and spice were analyzed to describe spatio-temporal variability. Internal-wave frequency spectra show a spectral slope lower than the Garrett-Munk (GM) model, and the energy level is 4% of the standard GM value. Frequency spectra of spice show a form similar to the internal-wave spectra but with a steeper spectral slope. Several global climate models were evaluated against historical and recent hydrographic observations and found to inadequately represent key upper-ocean hydrographic features. The Regional Arctic System Model (RASM) was used to investigate sensitivity of the simulated upper ocean to various configurations and showed that sub-grid scale brine rejection parameterization, appropriately tuned surface momentum coupling, and increased vertical and horizontal resolution improved model simulation. In both observational and model data sets, a near-surface sound channel is present, the significance and variability of which warrant further in-situ investigations and model improvements. Approved for public release; distribution is unlimited. Lieutenant Commander, United States Navy http://archive.org/details/observationsndmo1094551680