This thesis develops and applies a procedure to generate high quality 2D meshes for any given ocean region with complex coastlines. The different criteria used in determining mesh element sizes for a given domain are discussed, especially sizing criteria that depend on local properties of the bathymetry and relevant dynamical scales. Two different smoothing techniques, Laplacian conditioning and targeted averaging, were applied to the fields involved in calculating the sizing matrix. The L^2 norm was used to quantify which technique had the greatest preservation of the original field. In both the reduced gradient and gradient cases, targeted averaging had a lower L^2 norm. The sizing matrices were used as inputs for two mesh generators, Distmesh and GMSH, and their meshing results were presented over a set of ocean domains in the Gulf of Maine and Massachusetts Bay region. Further research into the capabilities of each mesh generator are needed to provide a detailed evaluation. Mesh quality issues near coastlines revealed the need for small scale feature size recognition algorithms that could be implemented and studied in the future.

Regional ocean models have long been integrated with acoustic propagation and scattering models, including work in the 1990s by Robinson and Lee. However, the dynamics in these models has been not inclusive enough to represent submesoscale features that are now known to be very important acoustically. The features include internal waves, thermohaline intrusions, and details of fronts. In practice, regional models predict internal tides at many locations, but the nonlinear steepening of these waves and their conversion to short nonlinear waves is often improperly modeled, because computationally prohibitive nonhydrostatic pressure is needed. To include the small-scale internal waves of tidal origin, a nested hybrid model is under development. The approach is to extract long-wavelength internal tide wave information from tidally forced regional models, use ray methods or mapping methods to determine internal-tide propagation patterns, and then solve two-dimensional high-resolution nonhydrostatic wave models to “fill-in” the internal wave details. The resulting predicted three-dimensional environment is then input to a fully three-dimensional parabolic equation acoustic code. The output from the nested ocean model, run in hindcast mode, is to be compared to field data from the Shallow Water 2006 (SW06) experiment to test and ground truth purposes

We know more about the dark side of the moon than the depths of the ocean. This is startling, considering how much more tangible the ocean is than space, and more importantly, how much more critical it is to the health and survival of humanity. Tens of billions of dollars are spent on manned and unmanned missions probing deeper into space, while 95% of Earth’s oceans remain unexplored. The result is a perilous dearth in knowledge about our planet at a time when rapid changes in our marine ecosystems profoundly affect its habitability.
The more intensive focus on space exploration is a historically recent phenomenon. For millennia until the mid-20th century, space and ocean exploration proceeded roughly at the same pace, driven by curiosity, military, and commerce. Both date back to early civilization when star-gazers scanned the skies, and sailors and free-divers scoured the seas. Since the 1960s when Don Walsh and Jacques Piccard descended to the deepest point on the ocean floor, and Neil Armstrong ascended to the moon, however, the trajectories of exploration diverged dramatically. Cold War-inspired geopolitical-military imperatives propelled space research to en extraordinary level, while ocean exploration stagnated in comparison. Moreover, although the Cold War ended more than 20 years ago, the disparity in effort remains vast despite evidence that accelerating changes in our marine ecosystems directly threatens our well being. Misconception about the relative importance of space and ocean exploration caused, and continues to sustain, this knowledge disparity to our peril.
In this thesis, we first review in section 2 the history of space and ocean exploration before the Cold War, when the pace of exploration in each sector was more or less comparable for thousands of years. We show in section 3, however, how the relative paces and trajectories of exploration diverged dramatically during the Cold War and continue to the present. In section 4 we seek to dispel the persistent misconceptions that have led to the disparity in resources allocated between space and ocean exploration, and argue for prioritizing ocean research. Finally, in section 5 we highlight the urgent imperative for expanding our understanding of the ocean.