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A Quad, describing CRUSER Seed Research Program funded research. CRUSER Funded Research FY22 Funded Research Proposal Consortium for Robotics and Unmanned Systems Education and Research (CRUSER)

The article of record as published may be found at https://doi.org/10.1029/2020JD032834 The constant flux layer assumption simplifies the problem of atmospheric surface layer (ASL) dynamics and is an underlying assumption of Monin‐Obukhov Similarity Theory, which is ubiquitously applied to model interfacial exchange and atmospheric turbulence. Within the marine environment, the measurements necessary to confirm the local ASL as a constant flux layer are rarely available, namely: direct observations of the near‐surface flux gradients. Recently, the Research Platform FLIP was deployed with a meteorological mast that resolved the momentum and heat flux gradients from 3 to 16 m above the ocean surface. Here, we present findings of a study assessing the prevalence of the constant flux layer within the ASL, using an approach that accounts for wave‐coherent turbulence, defines the wave boundary layer height, and empirically quantifies the observed flux divergence. Our analysis revealed that only 30‐40% of momentum flux gradients were approximately constant; for the heat fluxes, this increased to 50‐60%. The stationarity of local turbulence was critical to the constant flux layer's validity, but resulted in excising a large proportion of the observed profiles. Swell‐wind alignment was associated with momentum flux profile divergence under moderate wind speeds. In conjunction, our findings suggest that the constant flux layer, as it is conventionally defined, is not generally valid within the marine ASL. This holds significant implications for measuring air‐sea fluxes from single point sources and the application of Monin‐Obukhov similarity theory over the ocean. Office of Naval Research (ONR) This research was funded by the Office of Naval Research (ONR) Grant N0001418WX01087 under its Multidisciplinary University Research Initiative (MURI).

A Quad, describing CRUSER Seed Research Program funded research. Consortium for Robotics and Unmanned Systems Education and Research (CRUSER)

Approved for public release; distribution is unlimited Measuring atmospheric fluxes requires various steps of measurement quality control, in addition to experimental design and post-processing corrections, in order to provide robust and high-fidelity data for wider use. However, within the measurement community, methods for these control steps are still applied ad hoc. Regardless of the availability of several comprehensive references texts available in the literature and licensed software programs.The theoretical and technical design of an algorithm for eddy covariance flux sample quality control and assessment is presented. This algorithm, WISQ, is robust and efficient and can be readily incorporated into existing processing experimental software packages. The goal of this algorithm is to output a flagging system that can be used to judge the quality of individual flux samples, with the option for outputting more detailed information. WISQ is unique in that it directly and automatically assess the sample flux accumulation and convergence. WISQ is also a general method that can be utilized for flux measurement outside of the realm of meteorology and is open-sourced for ease in development and innovation.

Ocean Sciences Meeting 2020 Nonlinear internal ocean waves (NIWs) are regular features of the coastal ocean, where the hydrodynamic flow over changing bathymetry perturbs the isopycnal surfaces generating these high frequency waves. At the air-sea interface, these transient features may be characterized by quasilinear bands of smooth or rough ocean surface that propagate in the direction of the underlying NIWs. Theoretically, this roughness heterogeneity is driven by the phase-locked divergence and convergence of the NIW orbital motions. This NIW action modulates surface wavelengths within the capillary and gravity-capillary band, which also hold the majority of the tangential wind stress. Understanding the spatial-temporal distribution of these small-scale surface waves is critical to constraining air-sea coupling, which is significantly complicated in the case of a heterogeneous surface. The impact NIW-driven surface roughness has on the variability and structure of the atmospheric surface layer is unknown. During a Coupled Air Sea Processes and EM ducting Research (CASPER) field campaign, the Research Platform FLIP was deployed for five weeks in a coastal area with a suite of near-surface oceanographic and meteorological measurements, as well as near-field remote sensing of the surface using both radar, infrared, and optical visualization. This confluence of measurement capability from an ideal platform, enabled us to simultaneously identify and track NIWs while characterizing the variance and structure of the kinematic and thermodynamic state on either side of the interface. NIWs were regularly observed from FLIP, with their characteristic surface banding observed nearly every day of the campaign. Our analysis into one case revealed that NIWs exert a distinct and significant impact on the mean wind gradient, as well as the air-sea momentum flux (i.e. wind stress) on both the scale of individual wave fronts and an entire NIW packet. In particular, the MASL flow adjusts instantaneously to the smooth-rough transitions of individual bands, thereby enhancing the wind stress over the surface. Our presentation will focus on summarizing these findings, as well as highlighting additional NIW events observed during the CASPER campaign from FLIP to discern any underlying or general pattern in the nature of NIW-atmosphere interactions.

100th American Meteorological Society Annual Meeting. AMS, 2020. Monin-Obukhov Similarity Theory (MOST) forms the backbone for many studies of the atmospheric surface layer (ASL), whether over land or ocean, and is critical to predicting the electromagnetic (EM) propagation in the marine environment. Fundamentally, MOST extends the Richardson-Prandtl flux-gradient relationship to the general case of non-neutral conditions using dimensionless, empirical functions for momentum, temperature, moisture, and turbulent energy dissipation. These empirical functions provide a means to represent surface fluxes from mean quantities such as those from gridded numerical simulations. A critical component to the underlying basis for MOST, and the flux-gradient relationship, is the constant flux layer assumption. In the neutral conditions, the absence of stress divergence implies that only one relevant turbulent velocity scale is needed to close the surface flux problem (e.g., the friction velocity ). However, in the marine environment, flux profile measurements are rarely collected and the overwhelming majority of data sets cannot confirm the presence of this critical assumption over typical averaging windows. Using a complete (momentum and total heat), high-resolution flux profile (ranging 2-16 m above the surface) collected during the CASPER-West field campaign, we have conducted a study that systematically evaluates the prevalence of the constant flux layer model over the marine ASL (MASL). These measurements were taken from the Research Platform (R/P) FLIP, which is an ideal ocean-going platform for making near-surface measurements free from the contaminations endemic to typical ship-based measurements. We utilize a novel approach to empirically test each observed profile of momentum, sensible, and latent heat flux against a sufficiently constant profile. This enabled us to analyze the dependence of whether or not an individual profile was “constant” against the mean environmental state, e.g., wind speed, stability, and air-sea temperature difference. For the momentum flux, we found that only 33% of profiles could be considered non-divergent, which drops to 10% if only considering the profiles below 6 m. If only considering statistically stationary profiles (~20% of the total dataset), we found that 43% of profiles were sufficient constant stress. Similar findings were observed for sensible heat flux, with a dramatic increase in the prevalence of non-divergence for the latent heat flux. An analysis into the environmental dependence of these general results will be presented. These results question the generally held assumption that the MASL is typically a constant stress layer; this holds significant implications for how surface fluxes are parameterized and/or derived over the ocean, as well as the widespread reliance on MOST to accurately describe the vertical structure of the MASL.

2019 IEEE/OES Twelfth Current, Waves and Turbulence Measurement (CWTM) The article of record as published may be found at https://doi.org/10.1109/CWTM43797.2019.8955282 In the coastal environment, the oceanic flow over varying bathymetry can displace the isopycnal surfaces and, thus, generate nonlinear internal waves. These high frequency waves can propagate across large distances and over their lifetime significantly influence local currents and turbulence within a coastal region. These waves also create a common phenomenon that is recognized by even a casual observer: smooth, quasilinear bands of water that disrupt the typically rippled sea surface. While NIWs are an important oceanic process and their surface expression has been characterized and discussed for decades, investigators have not linked the presence of internal wave-driven surface roughness to an atmospheric response. Here we use a combination of oceanic and atmospheric measurements, as well as ocean surface visualization, to show that NIWs can alter the flow within the MASL and the subsequent momentum flux across the air-sea interface, at the dominant temporal-spatial scales of the NIWs. Our measurements were collected from the FLIP, which was deployed as part of the Coupled Air Sea Processes and Electromagnetic ducting Research (CASPER) West Coast field campaign. Using a thermistor chain, X band marine radar, upward- and downward-looking ADCP, as well as a visual field camera imaging the ocean surface near FLIP, we were able to identify several NIW events and track individual waves incident to the platform. This information was used to isolate the atmospheric response, as captured by a profile of meteorological flux sensors installed on a mast that was deployed from FLIP's boom. The observed NIW-interactions were found in multiple cases with different MASL conditions and internal wave properties. In the context of CASPER, the surface roughness associated with NIWs represents a persistent, quasi-Lagrangian heterogeneity that may impact the atmospheric gradients, which in turn modulates the index of refraction and the propagation of electromagnetic radiation. Office of Naval Research Funding provided by Office of Naval Research N0001418WX01087.

CRUSER Funded Research FY20 Funded Research Proposal CRUSER has funding to support NPS Faculty research focused on any aspect of unmanned systems/robotics related research. Researchers are selected based upon presentations at our spring Technical Continuum (TechCon) or our annual Call for Proposals. Proposals that support concepts from our current innovation thread are encouraged, but all research related to unmanned systems or robotics will be considered. Consortium for Robotics and Unmanned Systems Education and Research (CRUSER)

AGU Fall Meeting, 2019 Kolmogorov’s hypothesis for the presence of an inertial subrange exhibiting a power law scaling of -5/3 is one of the most widely recognized concepts in the fluid dynamics and remains an integral component of our general understanding of the turbulent cascade from energy-containing eddies to dissipation scales. While his theories have been debated since their proposal, its practical application to an observed turbulent field remains hampered by the lack of a systematic approach for identifying the bandwidth of this critical subrange. Within the atmospheric boundary layer literature, decades of studied has not yielded a standardized approach and the various methods reported appear ad hoc. This creates a significant hurdle to the applications of Kolmogorov’s theory to atmospheric boundary layer turbulence and the inter-comparison between disparate data sets. As part of a recent major field campaign conducted from the unique ocean- going platform the R/P FLIP, we developed the algorithm for robust identification of the inertial subrange (ARIIS) to study the inertial subrange characteristics within the atmospheric surface layer. ARIIS is a novel approach that explicitly uses the isotropic relationship between transverse velocity components to identify the onset and extent of the inertial subrange in the variance spectrum. After identifying the most plausible subrange bandwidth, ARIIS uses a robust, iterative fitting algorithm to derive an empirical estimate of the spectral slope, which can be compared to Kolmogorov’s expected -5/3 value. This presentation will discuss the implementation of ARIIS and describe the results of using this new method to conduct a systematic evaluation of Kolmogorov’s inertial subrange theory within the marine atmospheric surface layer using the FLIP data. Our findings provide compelling evidence for conditions where the inertial subrange slope diverges from -5/3, indicating that some other process(es), e.g. surface gravity waves, may play an integral role in the turbulence cascade near the air-sea interface.

Office of Naval Research v1.1: Additional text was added describing a review of some previous field campaigns conducted on the R/P FLIP, with focus placed on those investigators’ discussions of FLIP’s motion to various deployment schemes. This includes a new section (II.A.1) and an additional table (Table 1). These changes do not impact the results or analysis presented in v1. This document details the data processing, quality control and assessment analysis conducted on the instrumentation systems deployed by the Naval Postgraduate School Boundary Layer Processes research group as part of the CASPER-West field campaign. Approved for public release; distribution is unlimited.

99th American Meteorological Society Annual Meeting The bulk of our knowledge of air-sea exchange coefficients for momentum and heat derives from single-point measurements made at some height within the marine atmospheric surface layer (MASL). These point measurements rely on assumptions regarding the vertical structure of the MASL. Foremost among these assumptions, is the validity of Monin- Obukhov Similarity Theory (MOST), which postulates that the gradient-flux relationship is a universal function of surface layer stability. Under neutral conditions, this simplifies to the familiar logarithmic profile. While MOST has been validated over land, observations of the actual gradients within the MASL remain scarce, in part due to the challenges of making near-surface profile measurements over the ocean. The Research Platform FLIP was recently deployed on the west coast for the Coupled Air-Sea Processes and Electromagnetic ducting Research field campaign (CASPER-West), a large-scale air-sea interaction study that took place offshore of Pt. Mugu, CA. FLIP remains an ideal platform for making measurements in proximity to the air-sea interface, with minimal contamination from the platform. During CASPER, a meteorological mast was installed on FLIP that resolved both the bulk and flux profiles of momentum and heat, from 3 to 16 m above the surface. This mast included 7 flux levels, 10 mean wind measurements, and over 20 temperature and humidity probes. This presentation will focus on the vertical gradients measured from FLIP’s mast, with the specific aim of using these high-resolution measurements to test the variability predicted by MOST. As a preliminary step, linear regression was used to determine the natural prevalence of the logarithmic profile. For the mean wind profiles, only 10.2% of the profiles were strongly logarithmic (r2 > 0.9). For specific humidity, this increased to 40.9% of profiles, with no temperature profiles exhibiting a strong logarithmic relationship. Mean r2 was 0.624, 0.265, and 0.853 for wind, temperature, and specific humidity respectively, which increased to 0.761, 0.362, and 0.950 for wind speeds > 6 ms-1 (12.3% of the total data set). Wind speed exhibited positive, and temperature demonstrated negative, relationships with bulk air-sea temperature difference; for example, in stable conditions the mean r2 increased to 0.783 for wind speed, and decreased to 0.145 for temperature. Further analysis will focus on comparing strongly-logarithmic profiles to the empirical gradient-flux relationships available in the literature as well as, determining environmental factors driving the majority of profiles away from the expected logarithmic behavior. This unique dataset provides an opportunity to directly evaluate the prevalence and validity of the MASL vertical structure predicted by MOST, which is assumed to be generally valid over the ocean.

AGU Fall Meeting 2018 Nonlinear internal waves are readily observable in coastal waters, where flow over changing bathymetry may displace the isopycnal surfaces. These internal waves (IWs) may travel long distances, enhancing currents and turbulence within the upper ocean mixed layer. At the surface, IW fronts express as alternating smooth/rough water, creating transient heterogeneity that may disrupt the ambient gradients within the marine atmospheric surface layer (MASL) and hence the properties of the evaporation duct (ED). While the oceanic properties of IWs has been studied, their potential influence on the MASL remains largely unknown. Recently, the R/P FLIP was deployed for the Coupled Air-Sea Processes and Electromagnetic ducting Research (CASPER) program, an air-sea interaction study that took place offshore of Pt. Mugu, CA. As part of this effort, a meteorological mast with overlapping bulk and flux profiles for momentum, temperature, and water vapor was installed on FLIP, sampling the air column from 3 to 16 m above the surface. Using these data as well as high-resolution imagery of IW fronts propagating past FLIP, a study was conducted to determine the impact IWs have on MASL variability. The imagery of the IW bands was critical to enable tracking these features and directly relating measured variability to the presence of IWs. Preliminary findings suggest that the surface roughness variability associated with these IW fronts substantially affects the air-sea momentum flux. Strong flux divergence was found at the leading and trailing edges of each individual band, in some cases this divergence caused a sign reversal (i.e. upward momentum flux). This variability appeared to be trapped with individual bands, suggesting an impact on the MASL that may be distributed across the entire propagation range of a single IW front. Early analysis has not found a clear link between IW fronts and heat flux variability or divergence. However, these bands are visible at low winds and the observation of enhanced turbulence at their edges may impact the vertical scalar gradients (i.e. temperature and water vapor) and ultimately the predictability of the ED height. The results from this investigation, combining the measurements from the mast with observations from a co-located X-Band Marine Radar and a 40-m long thermistor chain, will be presented.

23rd Symposium on Boundary Layers and Turbulence/21st Conference on Air-Sea Interaction The Monin-Obukhov similarity theory (MOST) proposed that: given a logarithmic boundary layer, the gradients of the mean wind velocity, temperature, and water vapor within the surface layer are self-similar and universal functions of stability, respectively. While MOST is empirically supported, under certain conditions it has been demonstrated that the complex dynamics at the air-sea interface can erode the validity of the theory’s fundamental assumptions of homogeneity, stationarity, and no flux divergence. These limitations present a significant challenge to developing a general understanding of the MASL and therefore, further investigation is needed to address this critical gap. As part of this effort, the large-scale and field-based project, Coupled Air-Sea Processes and Electromagnetic ducting Research (CASPER), was specifically under-taken to provide new insights into the dynamics within the MASL combining the state-of-the-art measurement abilities of research vessels, platforms, and autonomous vehicles. This presentation will focus on the atmospheric and wave measurements made from an air-sea interaction mast mounted on the R/P FLIP during the second CASPER field campaign, which took place offshore of Southern CA during September and October of 2017. FLIP is an ideal platform for making undisturbed near-surface observations and reduces the operational challenges associated with making detailed measurements at sea from conventional research vessels. The platform was moored at 33° 41'20.40" N, 118° 59'24.00" W, which is 58 km southwest of Santa Monica and east of the Pt. Mugu Naval Sea Range, and was oriented into the seasonally-adjusted wind direction (~290°). The mast was installed on the port-side and comprised of 17 measurement levels representing overlapping bulk and flux profiles spanning from 3 m to 16 m above mean sea level. The 10 bulk-levels included two-dimensional wind and temperature/humidity probes. Six of the flux levels simultaneously measured the turbulent wind, temperature, and water vapor content, while the lowest level was only outfitted with a three-dimensional sonic anemometer. This recent FLIP data set represents one of the few extensive measurements of the near-surface water vapor gradient within the marine environment. The objective of this study is to investigate the effect non-stationarity and local heterogeneity has on the air-sea fluxes and mean profiles of wind velocity, temperature, and humidity. Preliminary examination of the data revealed 17 non-stationary cases, which were visually identified as strong, coherent deviations from the nominal condition. These events were found to be transient, but long-lived enough (typically 1-3 hours) to justify not classifying them as spurious measurements. Additionally, a review of the imagery acquired from a high-resolution camera mounted on FLIP’s face boom, showed the occasional presence of distinct short-wave anomalies (i.e. rough and smooth patches) advecting passed FLIP. During the campaign, some evidence indicated that these may be internal wave-driven surface expressions. The effects these surface discontinuities have on the fluxes and/or profiles within the MASL will be evaluated. The implications these non- stationary and locally heterogenic features have on the general dynamics and thermodynamics within the MASL will be discussed.

CRUSER TechCon 2018 Research at NPS. Wednesday 3: Applications Improved capability to model and forecast atmospheric effects on electromagnetic (EM) spectrum propagation in the battle-space has broad application throughout Navy and Department of Defense functional areas. Many Naval systems utilize the EM energy, active or passive, for applications in remote sensing (radar), communications (radio), and optical (high energy laser) systems. Refraction is an atmospheric property that bends EM energy from a straight-line path and is caused by spatial variations in temperature, humidity, and pressure. Meanwhile, small perturbations of the refraction index significantly impact free-space optical and high energy laser (HEL) weapon performance. These effects need to be quantified and predicted for all weather conditions. The Liquid Robotics Wave Glider, known as the Sensor Hosting Autonomous Remote Craft (SHARC) for Navy applications, is a slow-moving platform that can be deployed for extended missions. With adequate sensors onboard SHARC, environmental data can be collected in data sparse regions or hazardous environments. The standard SHARC is instrumented with a default meteorological station (Airmar PB200) that samples air pressure, temperature, wind speed and wind direction at 1.12 m above the water surface. The SHARC automatically transmits 10-minute averaged data through an Iridium satellite link. To maximize SHARC utilization in future Navy-relevant applications, NPS Meteorology Department partnered with the NPS Physics Department and engaged in integration and testing efforts to evaluate the default Airmar PB200 and sought optimal sensors for air-sea interaction and EM propagation studies. In this effort, we developed two SHARC payloads, the 'NPS Met� and �NPS Turbulence� systems. NPS Met payload measures pressure, air temperature, wind, SST, and relative humidity. This SHARC payload package was deployed three times in the Monterey Bay, along with a collocated drifting buoy (Marine Air-Sea Flux buoy, or MASFlux) with proven flux, mean, wave, and SST measurement for comparison and validation. NPS Met was augmented with a 3-D ultrasonic wind anemometer sensor and became the NPS Turbulence payload. Addition of the 20-Hz turbulence sampling required considerable modifications to the data acquisition and power management components. The NPS-owned Liquid Robotics WaveGlider SV2 (previously Mako, now named Thresher) was deployed with the turbulence payload during the Coupled Air-Sea Processes and EM ducting Research east coast field campaign (CASPER-East). Data collected from Thresher in CASPER-East were limited due to water ingress and salt corrosion inside the meteorological sensors and data acquisition system. The sensor payload configuration for Thresher was redesigned for the CASPER west coast field campaign (CASPER-West) to ensure continuous data collection during its deployment, while maintaining minimal flow distortions. In this presentation, we will showcase the Thresher payload design iterations, present example results from the met and turbulence payloads, and relate those results to the environmental impact on Navy operations using EM spectrum for sensing, communication, and weapon systems.

CRUSER TechCon 2018 Research at NPS. Wednesday 1: Sensing Small UAS (sUAS) are a cost-effective and easy to use solution to fill the niche between surface-based measurement platforms (e.g. buoys, WaveRider, etc.) and measurements with manned aircraft, providing a three dimensional view of the lower atmosphere. Due to their small size, sUAS can also be used in difficult to reach areas such as within a wind farm at altitudes that are difficult for tower based measurements. Because of these reasons, there have been many developments of sUAS in the past decades for meteorological applications. One important application of the sUAS-based environmental sampling is to quantify the lower atmosphere to initialize or constrain forecast models or as an independent validation for model evaluation, and may also be used to support tactical decisions, aiding in the prediction of electromagnetic (EM) wave propagation and propagation of high energy laser (HEL), where the atmospheric refractive properties are dependent on state variables such as pressure, temperature, and humidity in the lowest 2 km of the atmosphere. Quantifying the low level gradients of these variables is critical for predicting radar and communication signal and HEL propagations through the atmosphere. Our recent development in sUAS instrumentation focused on sensing capability to quantify optical turbulence in the lower atmosphere that has important applications in characterizing atmospheric effects on free-space optical communication and high energy laser weapon performance in the atmosphere. These electro-optical (EO) systems are mainly affected by atmospheric scintillation quantified by the structure function parameter(Cn2) of the atmospheric index of refraction. Although water vapor is one of the variables determining the index of refraction in the optical wavelength, a large component of Cn2 is the temperature structure parameter, CT2, and can be calculated with high-rate temperature perturbation measurements. Hence, our focus was on developing a payload to quantify high-rate temperature perturbations in addition to mean meteorological variables such as wind, temperature, humidity, and pressure. The airframe we use is adapted from the Finwing Penguin built for the first-person-viewpoint (FPV) hobby market. The airframe includes a raised pusher propeller scheme that places the propulsion downstream of the met sensors, and shields the operator from the propeller during hand-launches. The basic meteorological sensors include the self-recording multi-parameter weather sensor (InterMet XQ) and modified radiosonde (iMet-1) to obtain GPS coordinates, pressure, temperature, and relative humidity data. Data from the flight controller, pitot-static tube, and IMU systems were processed to retrieve mean wind speed and direction. For fast temperature measurements, we integrated a fine-wire (0.001 in) thermocouple and small diameter (0.02 in) Pt100 RTD probe into the Penguin. The thermocouple does not provide highly accurate measurements due to its non-linear response and the need for a second temperature measurement at the cold-junction. Albeit slower responding, the more accurate Pt100 temperature sensor is deployed to measure the mean air temperature and adjust the thermocouple's mean temperature component. In this presentation, we will introduce our effort of Penguin payload development. Results from the most recent Penguin test flights at McMillan Air Field, Camp Roberts, CA will be used to demonstrate the sampling capability. We will also show results from our ground evaluation tests at Marina Airport where the Penguin system made measurements side-by-side with proven sensors and data acquisition systems. The purpose of the ground test was to verify thermocouple amplifier provides sufficient time-resolution to resolve thermal plumes. The perturbation data from both sonic anemometer and Penguin data will be used to evaluate the capability of obtaining CT2 from a sUAS.

Wang, Qing: Principal Investigator Navy - ASN (RDA) NPS-17-N222-A

Naval Research Program NRWG Poster Office of Naval Research (ONR) HELJTO

NPS NRP Executive Summary Project Summary: This project addresses critical issues regarding the effects of low-level cloud/fog on the operational performance of high energy laser (HEL) weapons. This topic represents a large knowledge gap in operating the HEL weapons that inevitably goes through the atmosphere that is often filled with water hygrometers. This research included three parts: instrument development, field measurements, and data analyses. A fog microphysics sensor was modified to fit the application of measuring from a stationary platform and was integrated into a trailer-based laboratory for aerosol and fog sampling. For data collection, we made continuous measurements in two locations in the Monterey Bay area, one at a farm field at the coastline and one further inland over mostly concrete surface. These measurements include both meteorological data as well as propagation data. Data analyses focused on the observed scintillation and attenuation. The amount of optical energy attenuation through the fog layer and the role of scintillation in foggy conditions are being analyzed as part of the thesis work of Captain Zachary Daniels who will graduate in March 2019. ASN RDA Office of Naval Research (ONR) NPS-18-N343-A Approved for public release; distribution is unlimited.