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Fisheries management faces numerous monitoring and enforcement challenges that are becoming more complex as fish stocks are depleted; and illegal, unregulated, and unreported fishing becomes more sophisticated. For remote island nations, the challenges are compounded by a loosely understood association of pelagic stocks to the ocean environment, and the tyranny of distance in monitoring and surveilling large exclusive economic zones (EEZ). An approach to ocean conservation is establishing protected areas, with the Pacific island nation of Palau as a leader with the recently established National Marine Sanctuary, which closes 80% of their EEZ to commercial fishing in 2020. Here we present an EEZ-wide analysis of Palau commercial fishing over a 6-year period (2011–2016), and develop a system for predicting fishing activity accounting for oceanic variables, climate indices, and vessel flag. Linking pelagic habitat to fishing activity provides high-resolution decision aids for management, highlighting the need for EEZ-specific analyses in addressing fisheries.

Sea ice inhibits the development of wind‐generated surface gravity waves which are the dominant factor in upper ocean mixing and air‐sea fluxes. In turn, sea ice properties are modified by wave action. Understanding the interaction of ice and waves is important for characterizing both air‐sea interactions and sea ice dynamics. Current leading theory attributes wave attenuation primarily to scattering by ice floes. Here we use new in situ wave measurements to show that attenuation is dominated by dissipation with negligible effect by scattering. Time series of wave height in ice exhibit an ``on/off" behavior that is consistent with switching between two states of sea ice; a relatively unbroken state associated with strong damping (off), possibly caused by ice flexure, and very weak attenuation (on) across sea ice that has been broken up by wave action. Plain Language Summary Waves created by wind at the ocean surface are strongly attenuated when they travel across ice‐covered regions. Until now, this effect was thought to be the result of waves reflection off pieces of ice. Using new measurements of wave directions, we show that waves do not come for a broad range of directions, and scattering must be weak. Instead we find that attenuation is highly variable and related to the size of ice floes. We hypothesize that attenuation may be caused by cyclic deformation of the ice. When the waves are large enough to break the ice up, this deformation stops and the attenuation is much less. This finding is important for forecasting waves in ice‐infested waters as well as predicting seasonal sea ice extent.

The cross-shore evolution of nonlinear internal waves (NLIWs) from 8-m depth to shore was observed by a dense thermistor array and ADCP. Isotherm oscillations spanned much of the water column at a variety of periods. At times, NLIWs propagated into the surfzone, decreasing temperature by ≈1°C in 5 min. When stratification was strong, temperature variability was strong and coherent from 18- to 6-m depth at semidiurnal and harmonic periods. When stratification weakened, temperature variability decreased and was incoherent between 18- and 6-m depth at all frequencies. At 8-m depth, onshore coherently propagating NLIW events had associated rapid temperature drops (ΔT) up to 1.7°C, front velocity between 1.4 and 7.4 cm s−1, and incidence angles between −5° and 23°. Front position, ΔT, and two-layer equivalent height zIW of four events were tracked upslope until propagation terminated. Front position was quadratic in time, and normalized ΔT and zIW both decreased, collapsing as a linearly decaying function of normalized cross-shore distance. Front speed and deceleration are consistent with two-layer upslope gravity current scalings. During NLIW rundown, near-surface cooling and near-bottom warming at 8-m depth coincide with a critical gradient Richardson number, indicating shear-driven mixing.

Animals often select for habitats that increase their chance of survival by balancing the need to acquire food, reproduce and avoid predation. Perennial blooms of golden jellyfish (Mastigias papua etpisoni) are present in Jellyfish Lake, Palau, a popular tourist destination. Based on the species’ economic importance and unusual behavioural complexity, increased understanding of jellyfish habitat selection is necessary. We used a novel approach, a REMUS autonomous underwater vehicle, to quantify jellyfish distribution, abundance and habitat, and compared these findings to traditional methods. Midday acoustic surveys showed jellyfish distribution was patchy and the population resided mainly on the eastern side of the lake, as it is known that jellyfish migrate eastward towards the sun. Highest vertical densities of jellyfish were at 6–7 m, potentially to mitigate UV damage or photoinhibition of their photosymbionts, suggesting a coupling exists between their vertical distribution and water properties. Abundance estimates of jellyfish were ~2.75 and ~7.1 million (~2 million excluding bell diameters

Observations of hydrodynamics along with optical and acoustical water characteristics in a tropical fringing reef environment reveal a distinct signature associated with flow characteristics and tidal conditions. Flow conditions are dominated by tidal forcing with an offshore component from the reef flat during ebb. Measurements span variable wave conditions enabling identification of wave effects on optical and acoustical water properties. High-frequency acoustic backscatter (6 MHz) is strongly correlated with tidal forcing increasing with offshore directed flow and modulated by wave height, indicating dominant hydrodynamic influence. Backscatter at 300 and 1200 kHz is predominantly diurnal suggesting a biological component. Optical backscatter is closely correlated with high-frequency acoustic backscatter across the range of study conditions. Acoustic backscatter frequency dependence is used along with changes in optical properties to interpret particle-size variations. Changes across wave heights suggest shifts in particle-size distributions with increases in relative concentrations of smaller particles for larger wave conditions. Establishing a connection between the physical processes of a fringing tropical reef and the resulting acoustical and optical signals allows for interpretation and forecasting of the remote sensing response of these phenomena over larger scales.

Observations from around the main island group of Palau, located in the tropical Western Pacific, exhibit a persistent presence of baroclinic coastally trapped waves. The signals are found in records of temperature that were sustained on the fore-reef for seven months, May to December 2013, with the strongest signal from Typhoon Haiyan which passed over Kayangel Atoll, along with the northern most Palauan islands, in November of 2013. This strong forcing led to a large near- and sub-inertial response both in temperature and nearshore currents. We use semi-analytical models, such as the vertical structure equation and Brink and Chapman's (1985) model, to compute propagating modes for this oceanographic region providing a benchmark for comparison with the observations. These models provided a framework to account for the influence of local stratification, topography and the local Coriolis parameter on the wave guide around Palau. We found the maximum vertical displacements over the course of a 22-day period that included Typhoon Haiyan were 35.5 m and 45.7 m at the 57 m and 90 m isobaths, respectively, where temperatures ranged by 4.1 °C and 9.0 °C over that same period at those respective depths. The apparent omnipresence of coastally trapped waves throughout the observational window provide a regular cycling of temperature at depth, potentially conditioning benthic communities living on the outer reef slope to temperature swings.

The dominant source of coastal pollution adversely affecting the regional coastal water quality is the seasonally variable urban runoff discharged via southern California’s rivers. Here, we use a surface transport model of coastal circulation driven by current maps from high frequency radar to compute two-year hindcasts to assess the temporal and spatial statistics of 20 southern California stormwater discharges. These models provide a quantitative, statistical measure of the spatial extent of the discharge plumes in the coastal receiving waters, defined here as a discharge’s “exposure”. We use these exposure maps from this synthesis effort to (1) assess the probability of stormwater connectivity to nearby Marine Protected Areas, and (2) develop a methodology to estimate the mass transport of stormwater discharges. The results of the spatial and temporal analysis are found to be relevant to the hindcast assessment of coastal discharges and for use in forecasting transport of southern California discharges.

To characterize the transitional region from the near-field to far-field of a river plume entering coastal waters, we conducted four surveys using an autonomous underwater vehicle (AUV) to target the outflow of the New River Inlet, North Carolina, during maximum ebb tide. The utilization of a mobile sensor to synoptically observe current velocity data in tandem with natural river plume tracers (e.g., colored dissolved organic matter, salinity) was essential in understanding the mechanisms driving the observed circulation and mixing patterns within these waters. We find that this region is regularly impacted by two primary processes: (1) the interaction of an old dredged channel plume with the main discharge and (2) the recirculation of the discharge plume by an eddy that persistently forms between the old channel and main discharge location. Wind-driven processes in the nearshore can enhance the interaction of these two plumes resulting in unstable regions where mixing of the merged plume with the receiving waters is accelerated. We also conduct comparisons between AUV velocity observations from two surveys and their corresponding velocity outputs from a parallelized quasi-3-D model. We conclude that the ability to observe the estuarine outflow transitional region at near-synoptic temporal scales and resolutions discussed in this paper is key in providing the mechanisms driving local circulation which is essential for proper parameterization of high-resolution numerical coastal models.

[1] The network comprising 61 high-frequency radar systems along the U.S. West Coast (USWC) provides a unique, high resolution, and broad scale view of ocean surface circulation. Subinertial alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100–300) km d −1 that are consistent with historical in situ observations off the USWC and that can be possibly interpreted as coastally trapped waves (CTWs). The propagating signals in the slow mode are partly observed in southern California, which may result from scattering and reflection of higher-mode CTWs due to curvature of shoreline and bathymetry near Point Conception, California. On the other hand, considering the order of the phase speed in the slow mode, the poleward propagating signals may be attributed to alongshore advection or pressure-driven flows. A statistical regression of coastal winds at National Data Buoy Center buoys on the observed surface currents partitions locally and remotely wind-forced components, isolates footprints of the equatorward propagating storm events in winter off the USWC, and shows the poleward propagating signals year round.

The collection and processing of X-Band radar backscatter in the frequency-wavenumber domain holds promise for extracting information about ocean surface currents and vertical shear. The ability to sense this information remotely has potentially significant impacts on scientific, navigational, and military operations, especially in areas of energetic currents. We present results from an experiment conducted in a shallow, tidally forced river inlet. First, X-Band observations of wave dynamics in the highly energetic region of the Columbia River Inlet (OR, USA) are presented. Second, a bulk current retrieval technique is discussed. Finally, the presence of vertical current shear is shown to affect X-Band observations in the wavenumber dependence of current-induced Doppler shifts.

High resolution spatial and temporal observations are essential in determining mechanisms driving dynamic ocean processes. Mobile oceanographic sensors are often used to observe these processes at spatial resolutions unattainable by cast-based techniques. By undulating the sensor path (seesaw pattern), ocean parameters (e.g., velocity, salinity, colored dissolved organic matter (CDOM)) are profiled synoptically and utilized to characterize the process of interest. We present the methods employed to estimate velocity fields observed by a Doppler Velocity Log (DVL) deployed on an Autonomous Underwater Vehicle (AUV) during two field campaigns at New River, North Carolina, and Huntington Beach, California. In addition, we discuss the utilization of synoptic observations to characterize (1) the mixing region of the New River Inlet discharge during maximum ebb tide and (2) the nearshore discharge region of a wastewater outfall. The AUVs sampling resolution, adaptive sampling capabilities, and suite of instruments were key in determining the mechanisms of these processes.

This paper will primarily focus on the value of high-resolution wave measurements and high-frequency (HF) radar–derived surface currents on maritime operations, and the contributions of the Coastal Data Information Program (CDIP) and the Coastal Observing Research and Development Center (CORDC) on those measurements, respectively. Use case scenarios are presented to demonstrate operational applications utilizing wave and surface current measurements. Both CDIP and CORDC are based at the Scripps Institution of Oceanography and rely on multiple partnerships and collaborations. CDIP, primarily funded by the United States Army Corps of Engineers, manages and ingests data from over 60 coastal wave buoys, many of them at entries to ports and harbors, supporting near shore navigation. CORDC manages the data acquisition and near real-time processing of the U.S. High Frequency Radar network (HFRNet), a network that includes numerous participating organizations. These programs work in partnership with the U.S. Integrated Ocean Observing System (IOOS ® ). IOOS provides vital collaborations enabling tracking, predicting, managing, and adapting to changes in our ocean, coastal, and Great Lakes environment. Discussions continue with the commercial and recreational maritime community as to which types of observational products are needed in order to improve safety and efficiency. Both the wave and surface current data are available through web services and the IOOS regional organizations, such as the Southern California Coastal Ocean Observing system (SCCOOS).

Principal research goals are to characterize the physics and fluid dynamics which exist at the Mouth of the Columbia River. Coming from the relatively benign environment of the New River Inlet (RIVET I), this DRI will provide much stronger flows, larger waves, and more dynamic signals for our remote sensing instruments to observe. A by-product of the observational program will be the development of sensing capabilities that may have Naval interest.

Our long term goals are to improve our ability to characterize and forecast ocean surface waves. Most all at-sea Naval operations depend on knowledge of the conditions of the sea surface in one form or another. This includes the forecasting of EM/RF propagation near the ocean-surface as sea surface roughness has a profound influence on transmission characteristics. The world s oceans are data poor with respect to in-situ wave observations that are suitable for assimilation into, and verification with, operational global wave models (WAM, WaveWatch III). Data that is routinely available to models are satellite-based and have their own set of challenges. For example, remote sensing of the surface wave field using techniques such as radar altimetry or synthetic aperture radar (SAR) provides some measure of bulk wave properties, such as significant wave height or mean wave direction, and can be used to adjust global wave models. However, the techniques suffer from several issues: poor spectral resolution (e.g., differentiating swell vs. seas); the estimation of wave height is dependent on semiempirical models or modulation transfer functions that have inherent errors: and the satellite repeat time over a particular region of the ocean is too long to reliably improve. Global wave models suffer additional challenges as the wind forcing terms are derived from models (COAMPS, NOGAPS) that have their own set of data sparse challenges, and wave-current interactions are typically neglected due to poor measurements of ocean surface currents.

signals with phase speeds of O(10) and O(100 to 300) km day −1 and time scales of 2 to 3 weeks. The signals with slow phase speed are only observed in southern California. It is hypothesized that they are scattered and reflected by shoreline curvature and bathymetry change and do not penetrate north of Point Conception. The seasonal transition of alongshore surfacecirculationforcedbyupwelling‐favorablewindsandtheirrelaxationiscapturedinfine detail.Submesoscaleeddies,identifiedusingflowgeometry,haveRossbynumbersof0.1to3, diameters in the range of 10 to 60 km, and persistence for 2 to 12 days. The HFR surface currents resolve coastal surface ocean variability continuously across scales from

The San Diego/Tijuana border region has several environmental challenges with regard to assessing water quality impacts resulting from local coastal ocean discharges for which transport is not hindered by political boundaries. While an understanding of the fate and transport of these discharged plumes has a broad audience, the spatial and temporal scales of the physical processes present numerous challenges in conducting assessment with any fidelity. To address these needs, a data-driven model of the transport of both shoreline and offshore discharges is developed and operated in a hindcast mode for a four-year period to analyze regional connectivity between the discharges and the receiving of waters and the coastline. The plume exposure hindcast model is driven by surface current data generated by a network of high-frequency radars. Observations provided by both boat-based CTD measurements and fixed oceanographic moorings are used with the Roberts-Snyder-Baumgartner model to predict the plume rise height. The surface transport model outputs are compared with shoreline samples of fecal indicator bacteria (FIB), and the skill of the model to assess low water quality is evaluated using receiver operating characteristic (ROC) analysis.

This report describes the research performed on behalf of the Office of Naval Research to understand the influence of air-sea interaction processes on hyperspectral remote-sensing of the ocean's surface. The Hyperspectral Coupled Ocean Dynamics Experiment (HYCODE) and Monte Carlo Radiative model were used to investigate these processes, as well as newly refined acoustic techniques. A byproduct of this research will be models to correct for bubble mediated effects in measured hyperspectral light fields using wind and wave information. The program also presented an opportunity to develop techniques for inverting remotely-sensed hyperspectral imagery for in-situ bubble concentrations.

[1] Historical records of near-surface water temperatures in the Southern Californian Bight often show a preferential cooling in the lee of headlands such as Point Dume, Palos Verdes, and Point Loma. At times, this cooler water is associated with an increase in chlorophyll-a as is evident in satellite images of ocean color from the region. Here we combine hydrographic data from a 1 day cruise aboard the RV Roger Revelle (a precursor to the 0304 California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruise) with high-frequency (HF) radar (CODAR) measurements, satellite images, and long-term thermistor records of near-surface temperature to identify a small-scale, isolated upwelling in the lee of Point Loma (32.5°N). Associated with the more saline water downstream of the headland are higher nutrient concentrations, an increase in chlorophyll-a concentration, and a bloom of chain-forming diatoms, indicative of a mature upwelling system. It is suggested that this upwelling is not primarily due to local or remote wind forcing but rather to the divergence of the prevailing southerly flow as it passes the Point Loma headland. Time series of surface vorticity calculated from HF radar measurements of sea surface velocity show that as the flow separates from the headland, relative vorticity increases offshore of the cape. Inshore, the time series of divergence/convergence shows a tendency toward divergence at the surface, indicating a preferential upwelling which appears to raise the thermocline, thus resulting in a flux of cold nutrient-rich water to the surface. In the presence of high nutrients and light, photosynthetic organisms bloom in these upwelled waters as they are advected away from the headland and offshore by the prevailing surface currents.

The Third Acoustic Surface Reverberation Experiment (ASREX III) took place from December 1993 to March 1994 at Site L (34 deg N, 70 deg W) in the mid-Atlantic. As part of this experiment, two moorings were deployed to measure the environmental background. A meteorological and oceanographic mooring was deployed to characterize the surface wind stress, buoyancy flux, and the current and temperature structure over the top 500 meters. A Seatex Wavescan buoy was deployed to characterize the directional wave spectrum. This report presents results from these moorings. Wind speeds up to 25 m/s were seen, with significant heat losses (up to 1050 W/ sq. m) when cold continental air moved out over the warm Atlantic. The wave heights ranged up to 8 m, with significant wave heights of several meters persisting for relatively long periods. Wave height and period, nondirectional spectra, directional spectra and a typology of wave events are presented and related to surface forcing.