The Mid-Atlantic Regional Coastal Ocean Observing System (MARCOOS) High-Frequency Radar Network, which comprises 13 long-range sites, 2 medium-range sites, and 12 standard-range sites, is operated as part of the Integrated Ocean Observing System. This regional implementation of the network has been operational for 2 years and has matured to the point where the radars provide consistent coverage from Cape Cod to Cape Hatteras. A concerted effort was made in the MARCOOS project to increase the resiliency of the radar stations from the elements, power issues, and other issues that can disable the hardware of the system. The quality control and assurance activities in the Mid-Atlantic Bight have been guided by the needs of the Coast Guard Search and Rescue Office. As of May 4, 2009, these quality-controlled MARCOOS High-Frequency Radar totals are being served through the Coast Guard’s Environmental Data Server to the Coast Guard Search and Rescue Optimal Planning System. In addition to the service to U.S. Coast Guard Search and Rescue Operations, these data support water quality, physical oceanographic, and fisheries research throughout the Mid-Atlantic Bight.

High-frequency (HF) surface wave radar has been identified to be a gap-filling technology for Maritime Domain Awareness. Present SeaSonde HF radars have been designed to map surface currents but are able to track surface vessels in a dual-use mode. Rutgers and CODAR Ocean Sensors, Ltd., have collaborated on the development of vessel detection and tracking capabilities from compact HF radars, demonstrating that ships can be detected and tracked by multistatic HF radar in a multiship environment while simultaneously mapping ocean currents. Furthermore, the same vessel is seen simultaneously by the radar based on different processing parameters, mitigating the need to preselect a fixed set and thereby improving detection performance.

Results of Office of Naval Research (ONR)- and National Science Foundation (NSF)-sponsored collaborative coastal science experiments using underwater gliders were reported at the E.U./U.S. Baltic Sea conference in 2006. The National Oceanic and Atmospheric Administration (NOAA) recognized the parallel educational potential and issued a trans-Atlantic challenge—modify one of the coastal gliders and fly it across the Atlantic, entraining and inspiring students along the way. Leveraging the experience of the NSF Centers for Ocean Sciences Education Excellence, a needs assessment process guided the development of a new undergraduate research program based on the cognitive apprenticeship model. The generalized model was applied to the specific opportunities provided by the trans-Atlantic challenge, involving students in every aspect of the missions. Students participated in the modifications and testing required to increase glider endurance and in the development of the mission planning tools. Scientist and student teams conducted three long-duration missions: (1) RU15’s flight from New Jersey to Nova Scotia to test the lithium batteries and ruggedized fin technology in storms, (2) RU17’s first attempt at the Atlantic crossing that provided the lessons learned, and (3) RU27’s successful trans-Atlantic flight a year later. Post-flight activities included development of new intuitive glider data visualization software that enabled students to analyze the glider data and compare it with ocean forecast models, enabling students to create their own new knowledge. Lessons learned include the significant gains achieved by engaging students early, encouraging them to work as teams, giving them the tools to make their own discoveries, and developing a near-peer mentoring community for increasing retention and diversity. The success has inspired an even broader vision for international glider missions, that of a glider-enabled global classroom to repeat the track of the HMS Challenger and its first scientific circumnavigation of the globe.

A decade (2007-2016) of hourly 6-km-resolution maps of the surface currents across the Mid-Atlantic Bight (MAB) generated by a regional-scale High Frequency Radar network are used to reveal new insights into the spatial patterns of the annual and seasonal mean surface flows. Across the 10-year time series, temporal means and interannual and intra-annual variability are used to quantify the variability of spatial surface current patterns. The 10-year annual mean surface flows are weaker and mostly cross-shelf near the coast, increasing in speed and rotating to more alongshore directions near the shelfbreak, and increasing in speed and rotating to flow off-shelf in the southern MAB. The annual mean surface current pattern is relatively stable year to year compared to the hourly variations within a year. The 10-year seasonal means exhibit similar current patterns, with winter and summer more cross-shore while spring and fall transitions are more alongshore. Fall and winter mean speeds are larger and correspond to when mean winds are stronger and cross-shore. Summer mean currents are weakest and correspond to a time when the mean wind opposes the alongshore flow. Again, intra-annual variability is much greater than interannual, with the fall season exhibiting the most interseasonal variability in the surface current patterns. The extreme fall seasons of 2009 and 2011 are related to extremes in the wind and river discharge events caused by different persistent synoptic meteorological conditions, resulting in more or less rapid fall transitions from stratified summer to well-mixed winter conditions. Plain Language Summary A coordinated High Frequency Radar network operated between Cape Cod, MA, and Cape Hatteras, NC, generates hourly maps of ocean surface currents. A decade-long study revealed the detailed structure of the surface flows. These flows were compared to wind and river flow data to explain the patterns observed in the flow. Near the coast, the average currents flow offshore. Away from the coast, the average currents flow along the coast toward the south. Fall is the season with the most variability from year to year. Its higher variability can be traced to different regional weather patterns that change the wind fields and the amount of freshwater delivered by the rivers to the coastal ocean. This is the first study to use a decade of observed surface current maps that uniquely and simultaneously observe the changing patterns of the average flow structure along a segment of eastern United States. The improved understanding of the coastal circulation over a wide area, and what drives its variability, has implications for pollutant transport, plankton transport at the base of the food chain, fish and shellfish reproduction, and multiple ocean-based human activities including fishing, marine transportation, and offshore wind energy development.

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