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Our long-term scientific goals are to understand the dynamics and identify mechanisms of small-scale processes--i.e., internal tides, inertial waves, nonlinear internal waves, vortical modes, and turbulence mixing--in the ocean and thereby help develop improved parameterizations of mixing for ocean models. Mixing within the stratified ocean is a particular focus as the complex interplay of internal waves from a variety of sources and turbulence makes this a current locus of uncertainty. Our focus is on observing processes that lead to lateral mixing of water properties. The exploitation of autonomous platforms is a long-term goal. Our primary scientific objective is to use an innovative swarm of autonomous profilers to improve our understanding and parameterization schemes of small- to submeso-scale oceanic processes. Dispersion due to lateral processes with vertical and horizontal shears could enhance turbulent mixing. Both internal waves and vortical motions exist at vertical scales smaller than order of 10 m and horizontal scales smaller than few km. They have distinct kinematics and dynamics. Internal waves propagate and may carry energy to remote regions before they break and dissipate via turbulent processes, whereas vortical motions do not propagate and are often long lived. Separation of these two motions is necessary to improve parameterization schemes.

The overall objective of the proposed research is to collect detailed information about the thermal and physical state of the ice and ocean surface in the Beaufort and Chukchi seas in order to better understand the physical processes that control the melt, to better represent them in numerical models, and to better predict the seasonal evolution of the ice cover.

Physically-based parameterizations of vertical mixed layer fluxes in ocean models characterize turbulent mixing at length scales smaller than the layer depth, but neglect the dynamics of unresolved horizontal mixing processes below their O(1)-O(10) km horizontal resolution scale. Numerical modeling can be used to test new and existing scaling predictions of surface boundary layer horizontal mixing processes in regions of significant horizontal variability, as commonly found in major ocean fronts and coastal regions. The goal of numerical modeling work in this year of the DRI is to quantify relationships between surface fluxes of heat, energy and momentum, the available baroclinic potential energy, the resultant vertical mixing and geostrophic imbalance, and the ensuing dependence of lateral mixing at successively larger scales on atmospheric forcing. The objective in simulation analysis and model-data comparison is to develop dynamic scalings for the horizontal and vertical components of turbulent kinetic energy and fluxes in baroclinic upper ocean environments. These scalings will be used to compare with observations of lateral mixing and to tune modifications of existing upper ocean boundary layer models.

My longterm goals are understanding the smallscale ocean processes responsible for stirring and mixing in the ocean so that their impact on larger scales can be realistically parameterized. My interests includes phenomena ranging from the microscale (1 cm) up to the mesoscale (10-100 km) including internal waves, fronts, potential vorticity fine structure, turbulence production and salt-fingering.

The objectives are to: develop a sea state climatology for the Arctic Ocean, improve wave forecasting in the presence of sea ice, improve theory of wave attenuation/scattering in the sea ice cover, apply wave ice interactions directly in integrated arctic system models, and understand heat and mass fluxes in the air sea ice system.

The primary objective is to improve wave source/sink parameterizations by directly measuring the growth and dissipation of waves in the MIZ. The secondary objective is to develop a surface wave climatology of the arctic ocean and the relation to the seasonal MIZ.

Objectives: Existing high resolution regional models typically resolve the mean vertical structure of the upper ocean boundary layer. Physically-based parameterizations of vertical fluxes make it possible to account for subgrid mixing at length scales smaller than the layer depth, but no specialized parameterization is used to represent the dynamics of horizontal mixing below the O(1)km - O(10)km resolution scale. We aim to determine the physical limitations of subgrid parameterization on these scales. These projects address the following questions: * What physics govern horizontal and vertical mixing in the presence of horizontal variability on the 1-10 km scale? * What is the relative importance of horizontal and vertical mixing in determining the structure of the boundary layer? * What physics should be included to improve parameterizations?

The long-term goal is improving observations and understanding of major oceanographic features and phenomena. We emphasize motionally induced horizontal electric fields (HEF) and bottom pressure and Inverted Echo Sounders (PIES) for measuring ocean velocities from a bottom lander. The primary objectives of this observational program are to observe the North Equatorial Current (NEC) as it bifurcates into the Kuroshio and Mindanao currents (i.e., KC and MC, respectively) and determine the volume transports of the Kuroshio off NE Luzon Is. The plan was also to reveal interactions between the North Equatorial Current (NEC) and the strong mesoscale eddies. The HEF and PIES provided barotropic and baroclinic velocity components., Prepared in collaboration with the School of Oceanography, University of Washington, Seattle.

A group within the Applied Physics Laboratory of the University of Washington (APL-UW) dedicated to the use of autonomous underwater vehicles in support of Navy missions executed this program. The group generally uses the Seaglider, developed at APL-UW, and develops or adapts instruments and glider behavior to support specific mission requirements. This group is informally called the Applied Seaglider Group, whose acronym (ASG) is also used to describe the mission-adapted Seaglider itself. This report describes ongoing efforts as part of the ONR Passive Autonomous Acoustic Monitoring (PAAM) program. The original long-term goals of the PAAM program were as follows. a) Perform persistent and autonomous passive acoustic monitoring of a 500-1000 square nautical mile Navy exercise area for presence of marine mammals. b) Monitor for three weeks prior to, three weeks during, and three weeks after a typical exercise. c) Detect, classify and localize (DCL) vocalizing marine mammals. d) Provide actionable information in a timely manner to the officer in tactical command to support marine mammal mitigation efforts. Over the past several years, the long-term goals of the ONR PAAM program have changed to concentrate on the DCL mission in support of monitoring of marine mammals, particularly in Navy operating areas. In particular, a primary goal is to provide a persistent (many months) marine mammal monitoring capability in Navy operating areas that are remote or difficult to monitor by traditional means. These include the Hawaii, Gulf of Alaska, and Mariana Islands operating areas.

The long-term goal is to understand and predict key properties of the signal intensity vector field (Umov vector) as it propagates away from an active sound source, with emphasis is on mid-frequency, shallow water propagation. Because of enabling technologies involving MEMS and bio-inspired transduction, tomorrow s navy will depend on and utilize acoustic vector field properties (velocity, acceleration, intensity) much more than today s. Advancement in Navy relevant capabilities will be in part realized through a better understanding of the environmental and acquisition geometry dependence (source depth, range, etc.) of the vector field in a shallow water environment. The primary technical objectives this year were to: (1) Complete acoustic and sea surface wave modeling relating to the influence of sea surface directional waves on propagation measurements from the Shallow Water 06 (SW06) experiment off the coast of New Jersey and complete the analysis of the vector property known as circularity also using data from SW06. (2) Undertake the Targets and Reverberation Experiment (TREX13) off the coast of Florida. Here a new vector sensor from China was used in the first full-scale field test, following controlled laboratory testing from the previous year. These objectives share a common thread: towards understanding the environmental influences on the intensity vector field in shallow water sound propagation.

In the final year of this project, the primary objective was the application of the propagation model to synthetic aperture sonar simulations and simulations for scattering within a homogeneous waveguide. Refinements to image source enumeration were implemented to ensure that time-of-flight wave packets, associated with an image source, arrive at a receiver location within a time window of interest. The wave propagation model developed during FY11-12 was applied to several scattering problems, which included both waveguide simulations (i.e., reflections from upper and lower boundaries) and reduced half-space simulations (i.e., only interactions with a water-sediment interface). For the scattering problems, there are two wave propagation processes: (1) propagation from an image source to a target location, and (2) propagation from the target location to an image receiver. During step (1), the target location acts has a virtual receiver, and after the scattering process the target location becomes a virtual source. Thus, the refinement to the image source enumeration applies to the image receiver enumeration.

We are interested in the general problems of internal waves and ocean mixing. Knowledge of these is important for advancing the performance of operational and climate models, as well as for understanding local problems such as pollutant dispersal and biological productivity. In the specific case of nonlinear internal waves (NLIWs), the currents and displacements of the waves are strong enough to impact surface and under- sea operations. More generally, most of the ocean s physical and acoustic environments are severely impacted by internal waves. The pilot research described here will begin to improve our knowledge and predictive ability of NLIWs and their impacts on the Washington shelf. Additionally, it will form the foundation for better understanding of NLIW propagation and mixing on continental shelves worldwide.

The long-term goal of this research is development of computationally efficient physics-based methods for modeling of propagation, scattering, and reverberation in shallow waters with complicated spatial and temporal variability of environmental parameters. Scientific objective of this project is to develop a model of mid frequency reverberation for very shallow water environments. The model is to be relevant to specific conditions (1 10 kHz, 20 m water depth, 5 km range) of the ONR Target and Reverberation experiment [1] performed during the spring of 2013 (TREX13). This will result in developing codes for computer simulations to be used in TREX13 data analysis based on environmental inputs measured or/and typical for the chosen location. The research is to contribute to involving non-traditional approaches to better understand shallow water propagation and reverberation. This would support the idea expressed in the white paper [1], that a new area of investigation for WPRM (Wave Propagation in Random Media) should be suggested, to be relevant to TREX13 conditions. Particularly, for the chosen mid frequency range and very shallow waters, joint effects of the relatively large bottom penetration and 3D variability of the sediment properties, along with related effects of propagation, 3D refraction, and scattering within the seafloor, should be taken into account. Therefore, an approach is needed that treats heterogeneous stratified sediments as a critical part of the propagation channel (in addition to heterogeneous water column with rough boundaries).

The calibration and validation of surface wind and stress retrievals from oceanic synthetic aperture radar (SAR) imagery is especially difficult in tropical cyclone (TC) conditions. The geophysical model functions (GMFs) that characterize the radar backscatter in terms of the near-surface wind vector for different viewing geometries are currently poorly characterized for the very high wind and strong ocean surface wave conditions that are present in all TCs. Our long-term goal is to develop a novel methodology to use surface pressure observations and a planetary boundary (PBL) model for calibration and validation (Cal/Val) of SAR GMFs in TC conditions and to produce scene-wide wind vector retrievals that are most consistent with the image backscatter, the GMF and the PBL model. We further working toward an improved understanding of atmospheric boundary layer processes and air-sea interaction in tropical cyclones. The objectives of this research are to (1) develop the methodology for deriving TC SLP fields from first-guess surface wind vector estimates based on various GMF formulations; (2) Use these SLP fields to derive surface wind vector retrievals that are, in a least-squares sense, a scene-wide optimal surface wind retrieval that is consistent with the observable linear features in the SAR image, the GMF and the PBL model; (3) Develop an optimization scheme that seeks the minimum adjustment to the surface wind vector field that will minimize the difference between observed (e.g. via drop sondes or buoys) and SAR-derived bulk pressure gradients across the image. The optimized surface wind field can then be used either to assess or adjust the GMF.

The long-term goal is to understand mid-frequency (1-10 kHz) acoustics in shallow waters through measurements and modeling, including propagation, reflection, and forward- and backscatter, as well as reverberation. The top-level goals of this effort are to understand the important environmental processes that impact mid-frequency sonar performance in shallow water environments, and to develop means to efficiently collect those environmental data. The overall goal is to conduct a reverberation experiment in very shallow water off the coast of Panama City, Florida in FY13. This field project is part of TREX (Target and REverberation eXperiment). The frequency range is 1-10 kHz, emphasizing 3-4 kHz. The Navy relevance is reflected in the fact that detection using mid-frequency sonar is in most cases reverberation limited. This project addresses a clear need in basic research for a 6.1 level measurement program, using well-controlled geometries and high resolution environmental measurements, designed (1) to test models predicting reverberation and (2) to quantify the most important environmental measurements to make in order to maintain accuracy in those predictions. Data from such the experiment will be used for testing various forward and inversion techniques, and could also be used for training purposes. The water depth of the experiment is in the range of 15-25 m. The relevant water depth for naval applications covers the entire continental shelf. The key issue for reverberation is small grazing angle propagation and scattering in a waveguide. The major burden of such an experiment program is measuring the environment that influences reverberation. Reducing the region over which the environment needs to be measured becomes a primary consideration. By restricting the water depth to 15-25 m, the range at which the sound field is dominated by small grazing angle propagation and scattering is shorter than at deeper depths.

Our long-term scientific goals are to understand the upper ocean dynamics, to understand the coupling between the ocean and atmosphere via air sea fluxes, and to quantify the mechanisms of air sea interactions under extreme wind speeds. Our ultimate goal is to help develop improved parameterizations of air sea fluxes in ocean atmosphere models and parameterizations of small-scale processes in the upper ocean and the stratified interior. Tropical cyclones derive energy from the ocean via air sea fluxes. Oceanic heat content in the mixed layer and the air sea enthalpy flux play important roles in determining the storm s maximum potential intensity, structure, energy, trajectory, and dynamic evolution. The most energetic oceanic responses to tropical cyclone forcing are surface waves, wind-driven currents, shear and turbulence, and inertial currents. Quantifying the effect of these oceanic processes on air sea fluxes during tropical cyclone passage will aid understanding of storm dynamics and structure. The ocean s recovery after tropical cyclone passage depends upon small- and meso-scale oceanic processes in the storm s wake region. These processes are the least understood primarily because of the paucity of direct field observations under passing tropical cyclones; as a consequence, there are large uncertainties in air sea flux parameterizations in extreme wind regimes., Prepared in collaboration with the School of Oceanography, University of Washington, Seattle.

The long-range objectives of this research are to develop efficient accurate tools for quantitative forward modeling in range dependent, bottom-interacting acoustic propagation including sediment anisotropy and anelasticty. The specific objectives of this research are to develop practical theoretical and software tools for employing a fully elastic version of two-way coupled modes for modeling seismo-acoustic signals in shallow water with realistic elastic bottom properties, that may extend to elastically anisotropic sediment cover.

Our long-term scientific goals are to understand the dynamics and identify mechanisms of small-scale processes i.e., internal tides, inertial waves, nonlinear internal waves (NLIWs), and turbulence mixing in the ocean and thereby help develop improved parameterizations of mixing for ocean models. Mixing within the stratified ocean is a particular focus as the complex interplay of internal waves from a variety of sources and turbulence makes this a current locus of uncertainty. For this study, our focus is on the generation, propagation, evolution, and dissipation of small-scale internal waves and internal tides as the Kuroshio and barotropic tides interact with the two prominent submarine ridges in Luzon Strait. The primary objectives of this observational program are to quantify 1) the generation of NLIWs and internal tides in the vicinity of Luzon Strait, 2) the energy flux of NLIWs and internal tides into the Pacific Ocean and South China Sea (SCS), 3) the effects of the Kuroshio on the generation and propagation of NLIWs and internal tides, 4) the seasonal variation of NLIWs and internal tides, and 5) to study other small-scale processes, e.g., hydraulics and instabilities along internal tidal beams and at the Kuroshio front.

The long-term goal of this collaborative research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. The Arctic is projected to experience ice-free summers within 30 years (Wang & Overland, 2009). This will have significant impacts for the natural ecosystem dynamics and human use associated with transportation, fishing, military activity, and energy exploration. Baseline measurements will play an important role in mitigation efforts and environmental assessments as military activity increases in the region. A major component of this research is to use passive ambient sound to identify the physical environment present, and then to use this information to interpret the biological data collected.

The long-term goal of this project is a complete and accurate understanding of the properties of acoustic pulses sent over mesoscale to global scales. In particular, I want to understand the forward problem for calculating travel times of the early ray arrivals and late mode arrivals in long-range acoustic transmissions and to understand the sampling associated with those arrivals. The better the understanding of the forward problem, the better acoustic data can be used to understand the ocean. This work aims to develop models of ocean variability for understanding and predicting long-range acoustic propagation. Models of ocean variability, and therefore the associated sound speed variability, in the Philippine Sea are to be developed from historical data and from the PhilSea'09 and PhilSea'10 experiments, or adapted from existing efforts. Emphasis is placed on distinguishing between predictable (mesoscale, internal tides) and stochastic (internal waves) variabilities. These models will be used to obtain the relevant acoustic properties (e.g., full-depth sections of sound speed) such that the effects of variability on long-range acoustic propagation can be calculated and compared to field data. The work therefore aims to develop models for the physical oceanography of the central Philippine Sea with accurate and verified acoustical and oceanographic properties and with a quantified assessment of the predictability of the various model components.

The ultimate limitations to the performance of long-range sonar are due to ocean sound speed perturbations and the characteristics of the ambient acoustic noise field. Scattering and diffraction resulting from internal waves and other ocean processes limit the temporal and spatial coherence of the received signal, while the ambient noise field is in direct competition with the received signal. Research conducted in the North Pacific Acoustic Laboratory (NPAL) program at the Applied Physics Laboratory (APL-UW) is directed toward a complete understanding of the basic physics of low-frequency, long-range, deep water, broadband acoustic propagation, the effects of ocean variability on signal coherence, and the fundamental limits to signal processing at long-range that are imposed by ocean processes. The long-term goal of NPAL is to optimize advanced signal processing techniques, including matched-field processing and adaptive array processing methods, based upon knowledge about the multi-dimensional character of the propagation and noise fields and their impact on long-range ocean acoustic signal transmissions.

I am interested in the general problems of internal waves and ocean mixing. Knowledge of these is important for advancing the performance of operational and climate models, as well as for understanding local problems such as pollutant dispersal and biological productivity. SWIMS and MMP are valuable, highly capable instruments that will enable me to participate in many future ONR initiatives, complementing my other suite of moored profiling instruments.

The long-term goal is tho understand how the fundamental statistics of broadband low-frequency acoustical signals evolve during propagation through a dynamically-varying deep ocean, and how the oceanic ambient noise field varies throughout deep ocean battlespaces. Current models of signal randomization over long ranges in the deep ocean were developed for and tested in the North Pacific Ocean gyre. The first objective of this research is to determine the validity of these models in a region with different oceanographic features, specifically the Philippine Sea. The second objective is to continue an 18-year long experiment utilizing the North Pacific Ambient Noise Laboratory to determine whether models of oceanic ambient noise capture the spatial and temporal trends observed across the basin.

A significant source of uncertainty in parameterizations of ocean boundary layer dynamics lies in our inability to accurately represent the role of surface waves in upper-ocean Langmuir turbulence, and in the resulting mixed layer entrainment processes. This study contributes to our understanding of the role of waves and Langmuir turbulence in the context of high wind forcing by typhoons and hurricanes, and also contributes to our ability to consistently parameterize these processes across a much wider wide range of wind speed and sea state forcing conditions. This collaborative DRI is focused on measuring and modeling the response of the upper ocean to strong typhoons both in simple, open ocean conditions and in the more complex conditions caused by ocean eddies and preconditioning by prior storms. The measurement and modeling activities include a focus on the impact of surface waves, air-sea fluxes and the temperature, salinity and velocity structure of the upper ocean. The goals of this effort are to understand key upper ocean processes, test upper ocean models, develop and test new parameterizations of upper ocean physics used and study the feedback from the ocean to typhoon intensity.

Our long-term scientific goals are to understand the dynamics and identify mechanisms of small-scale processes i.e., internal tides, inertial waves, nonlinear internal waves (NLIWs), and turbulence mixing in the ocean and their interaction with mesoscale processes such as western boundary currents. We aim to develop improved parameterizations of mixing for ocean models. For this study, our focus is on the origin of the Kuroshio, the interaction among internal tides, internal waves, mesoscale eddies, and the Kuroshio, and the interaction of oceanic processes with the complex topography in Luzon Strait. The primary objectives of this observational program are to quantify the origin of the Kuroshio and to quantify its properties at the origin and as it evolves downstream.

This DURIP grant was directed towards the preparation for the Targets and Reverberation Experiment that occurred off Florida during the spring of 2013 (TREX13). Preparation included the procurement of instrumentation to measure the directional wave spectrum which is an important environmental driver to shallow water, mid-to-high frequency sonar performance in particular and underwater acoustic propagation in general. A primary objective was the purchase of a commercially available, directional wave buoy, with a second objective to use remaining funds for enhancing the capability of the acoustic receiving arrays for use in TREX13.

In collaboration with Indian oceanographers, we seek to measure and understand the processes controlling the stratification of the upper 100m of the Bay of Bengal and to educate a new generation of young Indian oceanographers in the methods used. Upper ocean physics plays a key role in controlling the intensity and timing of the Northern Indian Ocean monsoons, with the ocean and atmosphere representing a strongly coupled air-sea interaction system, which in turn plays an important role in climate variability at both regional and global scales. The ASIRI program, a Departmental Research Initiative of ONR s code 32, seeks to understand these interactions through measurement and modeling focused on the Bay of Bengal. Existing coupled ocean-atmosphere models in this region show little skill in predicting the summer monsoon, particularly its IntraSeasonal Oscillations (ISO). One possible cause is a poor simulation of the air-sea interaction processes. The northern Bay of Bengal has strong ISO fluctuations in SST, which lead the monsoonal fluctuations by about a week, thereby suggesting a causal relationship between monsoon ISO variations and ocean dynamics. However, most existing models predict surface temperatures that are too cold and mixed layer depths that are too deep. The biases are large and likely reduce the intensity of air-sea interaction by overestimating the thermal inertia of the upper ocean and thus the time scale on which the ocean can respond to the atmosphere. A likely reason for this bias is an improper representation of the role of freshwater input, both from rain and from the enormous river inflow into the northern Bay of Bengal.

We are interested in the general problems of internal waves and ocean mixing. Knowledge of these is important for advancing the performance of operational and climate models, as well as for understanding local problems such as pollutant dispersal and biological productivity. In the specific case of NLIWs, the currents and displacements of the waves are strong enough to impact undersea operations. More generally, most of the ocean s physical and acoustic environments (particularly in straits) are severely impacted by internal waves. The research described here substantially improves both our understanding and predictive ability of linear internal tides and NLIWs in Luzon Strait and the South China Sea., Additional grant no. N00014-09-1-0184.

I seek to understand the interactions between the ocean and tropical cyclones including typhoons and hurricanes. These grants support efforts in the TC10/ITOP (Tropical Cyclone 2010 / Impacts of Typhoons on the Ocean in the Pacific) program. This program, joint between ONR and Taiwanese investigators, studied the ocean response to typhoons in the western Pacific Ocean in 2010.

The overall scientific objective of the proposed effort is to improve our understanding of the propagation and mass transport of internal solitary waves (ISW), particularly mode-2 ISW, and their significance for coastal ocean processes. In recent years numerous observations of mode-2 ISW have been reported so that it appears that such waveforms may be more prevalent than previously thought. Large amplitude mode-2 solitary waves have unique properties, in particular they encompass regions of internal recirculation that enable mass transport over large distances. Transport of mass along a pycnocline can affect upper ocean mixing and distribution of biological and chemical constituents. Moreover, coherent ISW packets can have significant effects on the propagation and scattering of acoustic signals. The objectives of the current effort are to: (1) improve our fundamental understanding of mode-2 ISW mass transport including the effects of ambient shear; (2) characterize the three-dimensional mass transport from localized sources; and, (3) use the results to aid in the interpretation of ocean observations and ascertain the implications for ocean mixing and bio-chemical transport., Prepared in collaboration with the Dept. of Mechanical Engineering & Material Science, Duke University, Durham, NC.

The long-term goal is to demonstrate the significance of bio-alpha, attenuation due to large numbers of fish, on attenuation, transmission loss, scintillation index and reverberation in the ocean through at sea measurements and theoretical models. The objectives are to: Determine the effects of fish with swim bladders on attenuation (bio-alpha), transmission loss (TL), scintillation index (SI) and reverberation through an experiment off the west coast of the USA, and theoretical modeling. Demonstrate the effectiveness of range dependent (moving source) TL measurements for inferring bio-alpha - all previous bio-alpha measurements were conducted with fixed sources and receivers. Determine the effects of hake, a physoclists (volumes of their swim bladders are independent of depth) on bio-alpha, TL and SI - all previous bio-alpha experiments were conducted on physostomes (volumes of their swim bladders decrease with depth). Infer number densities of fish from bio-alpha measurements for comparison with number densities derived from echo sounder and trawl surveys. Determine effects of bio-alpha on reverberation.

Our long-term scientific goals are to understand the upper ocean dynamics, to understand the coupling between the ocean and atmosphere via air sea fluxes, and to quantify the mechanisms of air sea interactions. Our ultimate goal is to help develop improved parameterizations of air sea fluxes in ocean atmosphere models and parameterizations of small-scale processes in the upper ocean and the stratified interior. Tropical cyclones derive energy from the ocean via air sea fluxes. Oceanic heat content in the mixed layer and the air sea enthalpy flux play important roles in determining the storm s maximum potential intensity, structure, energy, trajectory, and dynamic evolution. The most energetic oceanic responses to tropical cyclone forcing are surface waves, wind-driven currents, shear and turbulence, and inertial currents. Quantifying the effect of these oceanic processes on air sea fluxes during tropical cyclone passage will aid understanding of storm dynamics and structure. The ocean s recovery after tropical cyclone passage depends upon small- and meso-scale oceanic processes in the storm s wake region. These processes are the least understood primarily because of the paucity of direct field observations under passing tropical cyclones; as a consequence, there are large uncertainties in air sea flux parameterizations in extreme wind regimes. The primary objective of this grant is to support a graduate student, Andy Hsu. He will pursue a Ph.D. degree with a focus on the process study of oceanic responses to tropical cyclones in the western Pacific observed during the ITOP intensive observation period using direct observations and numerical model simulations.

Our long-term goal is to use remote sensing observations to constrain a data assimilation model of wave and circulation dynamics in an area characterized by a river mouth or tidal inlet and surrounding beaches. As a result of this activity, we will improve environmental parameter estimation via remote sensing fusion, determine the success of using remote sensing data to drive DA models, and produce a dynamically consistent representation of the wave, circulation, and bathymetry fields in complex environments.

All numerical models (e.g., Numerical Weather Prediction models) have certain parameters within model algorithms which effect forecasts to a different degree, depending on the forecast quantity. The specific values of these model parameters are determined either theoretically using fundamental physics laws but incorporating necessary approximations to reduce computational cost, or empirically using observations from field experiments where observational error introduces uncertainty. In either case, the exact value of the parameter is often unknown a priori, and so their values are usually set to improve forecast quality through some form of forecast verification. Such an approach to model tuning, however, requires knowledge of the observations to which the forecasts must be compared, and therefore, a multitude of highly detailed experimental cases in order to fully resolve parameter values, a data set very difficult to obtain. A knowledge of the relationship between model parameters and forecast quantities, without reference to observations, can not only aid in such an observation-based approach to model tuning, it can also aid in tuning the model parameters according to other criteria that may not be based on observations directly, e.g., a desire to affect the forecasts according to some longterm experience of a forecaster. The main goal of our work has been to develop a framework for representing the complex relationship between model parameters and forecast quantities, without any reference to observations.

The overall goal of this project was to set up a simulation framework and testbed for ionosphere-thermosphere (IT) data assimilation that could be used to investigate: a) the impact of sensor systems upon the performance of data assimilation algorithms; b) the impact of improvements in data assimilative algorithms upon the performance of those data assimilative algorithms; c) the impact of different choices of inputs to data assimilative models and other configuration choices upon the performance of data assimilation algorithms. New ground and satellite data systems are constantly being proposed with different spatial-temporal configurations, and it is not clear what will maximize the impact on data assimilation performance. In particular, for this project, where the performance is quantized in terms of applications of interest to the Air Force, the metrics used to assess performance are applied systems metrics., The original document contains color images.

The Office of Naval Research initiated a Department Research Initiative (DRI) titled Sea State and Boundary Layer Physics of the Emerging Arctic Ocean. The central hypothesis of the Sea State DRI is that surface waves now have a much greater role in the contemporary Arctic Ocean. Indeed, the entire Arctic Ocean in summer may soon resemble a marginal ice zone (MIZ), where waves propagate through the ice pack and affect the evolution of sea ice over large scales. This large-scale pattern feeds back, as wave generation is controlled by the amount of open water fetch. At smaller scales, waves and ice interact to attenuate and scatter the waves while simultaneously fracturing ice into ever changing floe size and thickness distributions. Further complicating these processes are forcing by winds and surface fluxes from the ocean to the atmosphere, which are expected to increase with heightened storm activity in the region. The marginal open seas provide new opportunities and new problems. Navigation and other maritime activities become possible, but waves, storm surges and coastal erosion will likely increase. Air sea interactions enter a completely new regime, with momentum, energy, heat, gas, and moisture fluxes being moderated or produced by the waves, and impacting upper-ocean mixing., Sponsored in part by ONR grant numbers N00014-13-1-0290, MIPR-N0001413IP20046, N00014-13-1-0280, N00014-13-1-0288, MIPR-N0001413WX20830, MIPR-N0001413IP20050, N00014-13-1-0303, N00014-13-1-0446, MIPR-N0001413WX20825, N00014-13-1-0294, N00014-13-1-0279, N00014-13-1-0434, N0001413-1-0284 and N00014-13-1-0289.

The goal of this project is to develop a primer additive that mimics the self-healing ability of skin by forming a polymer scar across scratches. Designed to work with existing military grade primers, Polyfibroblast consists of microscopic, hollow zinc tubes filled with a moisture-cured polyurethane-urea (MCPU). When scratched, the foaming action of a propellant ejects the resin from the broken tubes and completely fills the crack. No catalysts or curing agents are needed since the polymerization is driven by ambient humidity.

This collaborative DRI is focused on measuring and modeling the response of the upper ocean to strong typhoons both in simple, open ocean conditions and in the more complex conditions caused by ocean eddies and preconditioning by prior storms., The original document contains color images.

Despite their prevalence in shallow water environments, sand sediments remain poorly understood acoustic media, with one of the largest gaps in our understanding lying at the high (100 kHz) frequencies. This lack of understanding has important consequences for many practical applications including the remote sensing of sediment properties. The goal of the proposed research was to further develop and test models of volume scattering by utilizing the existing suite of instrumentation previously developed at APL-UW for the study of high-frequency acoustics. In order to perform the data/model comparisons, extensive environmental characterization was also to be performed in the pond and at-sea., The original document contains color images.

We performed research in the field of electromagnetic wave chaos and High Power Microwave (HPM) effects in electronic systems. Our emphasis was on issues likely to be most relevant to the coupling of electromagnetic radiation into systems and its effects on systems, as in electromagnetic attacks of military electronics.. Our program addressed the following issues of relevance to the understanding of HPM effects on electronic systems: The extension of the previously developed Random Coupling Model statistical description of wave coupling into enclosures to describe a) the coupling through apertures, b) the coupling to mixed systems for which only part of the ray phase space is chaotic, and c) the coupling to systems of systems in which the components have varying degrees of isolation, for example chains of cavities. The further development of time domain models for the response of systems excited by pulses of wave energy, including nonlinear effects The Extension of HPM upset experimentation and modeling to complex networks of interconnected circuits. Our aim is to develop a generalized approach for modeling HPM effects in electronic circuits, systems and infrastructures. Examination of fading, power-delay profiles, and small-signal discrimination in reverberant electromagnetic environments containing short-ray trajectories., The original document contains color images.

The long-term goal of this collaborative research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. The Arctic is projected to experience ice-free summers within 30 years (Wang & Overland, 2009). This will have significant impacts for the natural ecosystem dynamics and human use associated with transportation, fishing, military activity, and energy exploration. Baseline measurements will play an important role in mitigation efforts and environmental assessments as military activity increases in the region. A major component of this research is to use passive ambient sound to identify the physical environment present, and then to use this information to interpret the biological data collected., The original document contains color images.

When the quality of service (QoS) of an unmanned air vehicle's (UAV) communications link is poor, and the UAV is tracking a moving target, a trade-off exists between the fidelity and timeliness of information provided from the vehicle to an operator. The authors' 2011 ICCRTS paper showed that an optimal representation scheme for transmitting information from UAV to operator can be found by using information theory. This paper extends that work by introducing an adaptive, autonomous UAV command and control system that autonomously changes the fidelity of information communicated to an operator in response to variances in communications QoS. Results and analysis of hardware-in-the-loop experiments using a UAV that is tracking a moving car are presented. The paper also examines the impact of information decay and network performance on both human tele-operation and on-board autonomous control, comparing the relative performance of tele-operation and autonomy as a function of entropic drag, which is a measurement, in information theory bits, of the rate at which information is lost due to unpredictable changes in the environment. In the experiments described in this paper, entropic drag is produced by the movement of the vehicle being tracked., Presented at the 18th International Command and Control Research and Technology Symposium (ICCRTS) C2 in Underdeveloped, Degraded and Denied Operational Environments held in Alexandria, VA, on 19-21 June 2013. U.S. Government or Federal Rights License.

We present the measurement of squeezed light generation using an engineered optomechanical system fabricated from a silicon microchip and composed of a micromechanical resonator coupled to a nanophotonic cavity. Laser light is used to measure the fluctuations in the position of the mechanical resonator at a measurement rate comparable to the free dynamics of the mechanical resonator, and greater than its thermal decoherence rate. By approaching the strong continuous measurement regime we observe, through homodyne detection, non-trivial modifications of the reflected light's vacuum fluctuation spectrum. In spite of the mechanical resonator's highly excited thermal state (10,000 phonons), we observe squeezing at the level of 4.5 plus or minus 0.5% below that of shot-noise over a few MHz bandwidth around the mechanical resonance frequency of 28 MHz. This squeezing is interpreted as an unambiguous quantum signature of radiation pressure shot-noise., Sponsored in part by DARPA.

Our long-term scientific goals are to understand the dynamics and identify mechanisms of small-scale processes in the ocean with the objective of developing improved parameterizations of mixing for ocean models. Internal tides, inertial waves, nonlinear internal waves (NLIWs), and turbulence mixing are all key components to understanding mixing within the stratified ocean. Each of these factors can lead to uncertainty within current ocean models due to their complex interplay. This study focuses primarily on small-scale processes, internal tides, and also key circulation features including cold dome events localized at the continental slope of the East China Sea (ECS) and intrusions generated as the Kuroshio and barotropic tides interact with the continental shelf of the ECS. These small-scale processes and circulation features modulate the temporal, horizontal, and vertical spatial structures of the water properties of the ocean. These processes may significantly modify acoustic properties and thus introduce uncertainty into sonar performance and acoustic propagation models. Our ultimate goal is to collaborate with acousticians to identify oceanic processes that alter acoustic properties. A detailed understanding of these properties, mechanism, and dynamics will aid in quantification and assessment of uncertainty in acoustic prediction., The original document contains color images.

The degree of circularity is a vector quantity relating to the acoustic particle motion induced in an acoustic field, and is formulated by measurements of the acoustic particle velocity or the complex vector intensity. It characterizes the ellipticity of the particle motion path that, for example, can arise when there is interference between a source signal and its reflections. In an ocean waveguide the spatial dependence of this vector property depends on the water column sound-speed, surface conditions and bottom properties, in addition to the source/receiver geometry. In waveguides with nearly horizontal boundaries, the vertical component of the instantaneous intensity can be used to provide an approximation to the degree of circularity. This approximation, applied to acoustic pressure measurements from two closely spaced hydrophones made in 2006 off the New Jersey coast in waters 80 m deep, is used to invert for environmental parameters of the sediment structure.

In combination with an appropriate background ocean model, simulations of internal waves are necessary to create realistic scenarios for use in acoustic propagation studies. Our approach employs contemporary understanding of internal wave statistics with a simulator that produces two-dimensional (range/depth) slices of internal wave displacements. The method produces statistical realizations for acoustic studies that are true to ocean measurements with nominal computational cost., The original document contains color images.

In order to improve ship self-defense against sea-skimming missiles, several concepts, such as the free electron laser, high-power microwaves, and the Phalanx gun system are reviewed and evaluated in this thesis. Phalanx computer simulations show that Phalanx is an inadequate means of protection. High-power microwaves are found to damage electronics, but calculations show limitations due to diffraction and the possibility of shielding. This thesis evaluates several damage mechanisms caused by the free electron laser's ultra- short picosecond pulse. Theories and experiments predicting the laser damage from short picosecond pulses are reviewed and applied to the fel weapon design. It is found that there may be a significant advantage to the ultra-short pulse format of an FEL weapon; as a result, new experiments are planned. As MW FELs are not yet a reality, this thesis uses computer simulations to explore FEL operation for many values of the electron pulse length, peak current and cavity desynchronism in order to explain recent Thomas Jefferson National Accelerator Facility (TJNAF) experimental observations of high average power., http://archive.org/details/antishipmissiled1094532646, NA, U.S. Navy (U.S.N.) author., Approved for public release; distribution is unlimited.

As the Navy's role as peace enforcer in support of ground troops draws Navy combatants into the littoral warfare environment, surface combatants will have to deal with decreased reaction times while engaging ever faster antiship missile threats. The Phalanx Close In Weapon System (CIWS) does not offer sufficient accuracy or engagement ranges to fight these threats, and conventional chemical lasers, which operate at fixed wavelengths, lack the tunability to operate in a dynamic ocean environment. The Free Electron Laser (FEL) offers the wavelength tunability, fast reaction times, and the pinpoint accuracy necessary to ensure protection of Navy surface combatants into the future. In support of this goal, the Navy is funding a proposed 20 kW FEL at Thomas Jefferson National Accelerator Facility (TJNAF) in Newport News, VA. This FEL will feature a klystron undulator, designed to improve gain in weak optical fields, and a loop that will feed electrons back to the accelerator. Simulations in this thesis vary the dispersive section strengths of the klystron undulator and desynchronism between the optical and electron pulses in order to find dispersive strength and desynchronism values that optimize the effects on final power and weak field gain, while maintaining an electron energy spread less than TJNAF's goal of 6% to ensure proper feedback of electrons to the accelerator. Results show TJNAF's 20 kW FEL design will reach a final power of 19.2 kW with an energy spread of 6% at desynchronism of d=0.03 using a conventional undulator, http://archive.org/details/simulationsofpro1094526768, Lieutenant, United States Navy, Approved for public release; distribution is unlimited.

Computer simulation is a valuable tool for the research of physics. These simulations can be especially valuable when there is experimental data available that can be used to validate the model. The main objective of this thesis is to determine whether a computer simulation model can accurately depict the experimentally determined fluid flow for a channel with a series of unique individual constrictions. The experimental data are derived from a scaled-up model of coronary blood flow with localized axisymmetric constrictions (or stenoses), representing an ideal case of atherosclerotic disease. This thesis provides the foundation for future study and simulation to develop a microelectromechanical device mounted on a stent capable of sensing and transmitting changes in blood flow characteristics and properties to an outside receiver for improved treatment of patients with atherosclerotic coronary artery disease.