Swezey, M., 2016. Ocean Acoustic Uncertainty for Submarine Applications. SM Thesis, Massachusetts Institute of Technology, MechE-USN Joint Program, June 2016.
The focus of this research is to study the uncertainties forecast by multi-resolution
ocean models and quantify how those uncertainties affect the pressure fields estimated
by coupled ocean models. The quantified uncertainty can then be used to provide
enhanced sonar performance predictions for tactical decision aides.
High fidelity robust modeling of the oceans can resolve various scale processes
from tidal shifts to mesoscale phenomena. These ocean models can be coupled with
acoustic models that account for variations in the ocean environment and complex
bathymetry to yield accurate acoustic field representations that are both range and
time independent. Utilizing the MIT Multidisciplinary Environmental Assimilation
System (MSEAS) implicit two-way nested primitive-equation ocean model and Error
Subspace Statistical Estimation scheme (ESSE), coupled with three-dimensional-inspace
(3D) parabolic equation acoustic models, we conduct a study to understand and
determine the effects of ocean state uncertainty on the acoustic transmission loss.
The region of study is focused on the ocean waters surrounding Taiwan in the East
China Sea. This region contains complex ocean dynamics and topography along the
critical shelf-break region where the ocean acoustic interaction is driven by several
uncertainties. The resulting ocean acoustic uncertainty is modeled and analyzed to
quantify sonar performance and uncertainty characteristics with respect to submarine
counter detection. Utilizing cluster based data analysis techniques, the relationship
between the resulting acoustic field and the uncertainty in the ocean model can be
characterized. Furthermore, the dynamic transitioning between the clustered acoustic
states can be modeled as Markov processes. This analysis can be used to enhance
not only submarine counter detection aides, but it may also be used for several applications
to enhance understanding of the capabilities and behavior of uncertainties
of acoustic systems operating in the complex ocean environment.