Scientific Papers

Partnership between the private sector and the ocean observing community brings exciting opportunities to address observing challenges through leveraging the unique strengths of each sector. Here, we discuss a case study of a successful relationship between the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory (PMEL) and Saildrone to instrument an Unmanned Surface Vehicle (USV) in order to serve shared goals. This case study demonstrates that a private company working with a federal laboratory has provided innovative ocean observing solutions deployed at regional scale in only a few years, and we project that this model will be sustainable over the long-term. An alignment of long-term goals with practical deliverables during the development process and integrating group cultures were key to success. To date, this effort has expanded NOAA’s interdisciplinary observing capabilities, improved public access to ocean data, and paved the way for a growing range of USV applications in every ocean. By emphasizing shared needs, complementary strengths, and a clear vision for a sustainable future observing system, we believe that this case study can serve as a blueprint for public and private partners who wish to improve observational capacity. We recommend that the international scientific community continue to foster collaborations between the private sector and regional ocean observing networks. This effort could include regional workshops that build community confidence through independent oversight of data quality. We also recommend that an international framework should be created to organize public and private partners in the atmospheric and oceanographic fields. This body would coordinate development of observational technologies that adhere to best practices and standards for sensor integration, verification, data quality control and delivery, and provide guidance for unmanned vehicle providers. Last, we also recommend building bridges between the private sector, ocean observing community, and the operational forecast community to consider the future of this new private sector, with goals to determine targeted ocean observing needs; assess the appropriateness of USVs as science platforms, sensors, and data format standards; and establish usage and data quality control and distribution protocols for ocean observing and operational forecasting.

Turbulent and radiative exchanges of heat between the ocean and atmosphere (hereafter heat fluxes), ocean surface wind stress, and state variables used to estimate them, are Essential Ocean Variables (EOVs) and Essential Climate Variables (ECVs) influencing weather and climate. This paper describes an observational strategy for producing 3-hourly, 25-km (and an aspirational goal of hourly at 10-km) heat flux and wind stress fields over the global, ice-free ocean with breakthrough 1-day random uncertainty of 15 W m–2 and a bias of less than 5 W m–2. At present this accuracy target is met only for OceanSITES reference station moorings and research vessels (RVs) that follow best practices. To meet these targets globally, in the next decade, satellite-based observations must be optimized for boundary layer measurements of air temperature, humidity, sea surface temperature, and ocean wind stress. In order to tune and validate these satellite measurements, a complementary global in situ flux array, built around an expanded OceanSITES network of time series reference station moorings, is also needed. The array would include 500–1000 measurement platforms, including autonomous surface vehicles, moored and drifting buoys, RVs, the existing OceanSITES network of 22 flux sites, and new OceanSITES expanded in 19 key regions. This array would be globally distributed, with 1–3 measurement platforms in each nominal 10° by 10° box. These improved moisture and temperature profiles and surface data, if assimilated into Numerical Weather Prediction (NWP) models, would lead to better representation of cloud formation processes, improving state variables and surface radiative and turbulent fluxes from these models. The in situ flux array provides globally distributed measurements and metrics for satellite algorithm development, product validation, and for improving satellite-based, NWP and blended flux products. In addition, some of these flux platforms will also measure direct turbulent fluxes, which can be used to improve algorithms for computation of air-sea exchange of heat and momentum in flux products and models. With these improved air-sea fluxes, the ocean’s influence on the atmosphere will be better quantified and lead to improved long-term weather forecasts, seasonal-interannual-decadal climate predictions, and regional climate projections.

A successful integrated ocean acidification (OA) observing network must include (1) scientists and technicians from a range of disciplines from physics to chemistry to biology to technology development; (2) government, private, and intergovernmental support; (3) regional cohorts working together on regionally specific issues; (4) publicly accessible data from the open ocean to coastal to estuarine systems; (5) close integration with other networks focusing on related measurements or issues including the social and economic consequences of OA; and (6) observation-based informational products useful for decision making such as management of fisheries and aquaculture. The Global Ocean Acidification Observing Network (GOA-ON), a key player in this vision, seeks to expand and enhance geographic extent and availability of coastal and open ocean observing data to ultimately inform adaptive measures and policy action, especially in support of the United Nations 2030 Agenda for Sustainable Development. GOA-ON works to empower and support regional collaborative networks such as the Latin American Ocean Acidification Network, supports new scientists entering the field with training, mentorship, and equipment, refines approaches for tracking biological impacts, and stimulates development of lower-cost methodology and technologies allowing for wider participation of scientists. GOA-ON seeks to collaborate with and complement work done by other observing networks such as those focused on carbon flux into the ocean, tracking of carbon and oxygen in the ocean, observing biological diversity, and determining short- and long-term variability in these and other ocean parameters through space and time.

Two saildrones participated in the Salinity Processes in the Upper-ocean Regional Study 2 (SPURS-2) field campaign at 10°N, 125°W, as part of their more than six-month Tropical Pacific Observing System (TPOS)-2020 pilot study in the eastern tropical Pacific. The two saildrones were launched from San Francisco, California, on September 1, 2017, and arrived at the SPURS-2 region on October 15, one week before R/V Revelle. Upon arrival at the SPURS-2 site, they each began a two-week repeat pattern, sailing around the program’s central moored surface buoy. The heavily instrumented Woods Hole Oceanographic Institution (WHOI) SPURS-2 buoy serves as a benchmark for validating the saildrone measurements for air-sea fluxes. The data collected by the WHOI buoy and the saildrones were found to be in reasonably good agreement. Although of short duration, these ship-saildrone-buoy comparisons are encouraging as they provide enhanced understanding of measurements by various platforms in a rapidly changing subsynoptic weather system. The saildrones were generally able to navigate the challenging Intertropical Convergence Zone, where winds are low and currents can be strong, demonstrating that the saildrone is an effective platform for observing a wide range of oceanographic variables important to airsea interaction studies.

This report provides: 1) a detailed description of the acoustic-trawl method (ATM) used by NOAA’s Southwest Fisheries Science Center (SWFSC) for direct assessments of the dominant species of coastal pelagic species (CPS; i.e., Pacifc Sardine Sardinops sagax, Northern Anchovy Engraulis mordax, Pacifc Mackerel Scomber japonicus, Jack Mackerel Trachurus symmetricus, and Pacifc Herring Clupea pallasii) in the California Current Ecosystem (CCE) o ̇ the west coast of North America; and 2) estimates of the biomasses, distributions, and demographies of those CPS in the survey area between 26 June and 23 September 2018. The survey area spanned most of the continental shelf between the northern tip of Vancouver Island, British Columbia (BC) and San Diego, CA. Throughout the survey area, NOAA Ship Reuben Lasker (hereafter, Lasker) sampled along transects oriented approximately perpendicular to the coast, from the shallowest navigable depth (~30 m depth) to either a distance of 35 nmi or to the 1,000 fathom (~1830 m) isobath, whichever is farthest. Between approximately San Francisco and Pt. Conception, additional acoustic sampling was conducted along 4 nmi-long transects spaced 5-nmi apart using a wind- and solar-powered unmanned surface vehicle (USV; Saildrone, Inc.) in the nearshore where Lasker could not safely navigate.

As part of the Tropical Pacific Observing System (TPOS)-2020 project, two Saildrone Inc. "Saildrones" were deployed in the tropics to assess the capability of these innovative unmanned surface vehicles as potential platforms within the TPOS. Saildrone measurements include wind speed and direction, air- and sea-surface temperature, humidity, barometric pressure, downwelling solar and longwave radiation, surface salinity, upper ocean currents from a RDI-300 KHz workhorse acoustic Doppler current profiler, and a full suite of biogeochemistry measurements. Comparisons between the drone data and surface flux buoys show good agreement, confirming that this platform can make climate-quality meteorological and oceanographic observations. During the 6-month mission, La Niña conditions prevailed, and large-amplitude tropical instability waves propagated along the strong cold-tongue front. Saildrone measurements resolve not only the strong cold-tongue but also abrupt submesoscale fronts. The two Saildrones each traversed the northern edge of the equatorial cold tongue twice. Saildrones observed multiple abrupt fronts equatorward of the cold-tongue front with temperature and salinity changes as large as 1ºC and 0.3 psu, respectively, in less than 1 km. These sharp temperature fronts have the potential to result in large air-sea fluxes because air blowing across these fronts cannot equilibrate with the sea surface on such short length scales. Saildrone, with its high-resolution and adaptive sampling, offers the opportunity to document intense air-sea interaction associated with these abrupt fronts.

Abstract: Saildrones are unmanned surface vehicles engineered for oceanographic research and powered by wind and solar energy. In the summer of 2016, two Saildrones surveyed the southeastern Bering Sea using passive acoustics to listen for vocalizations of marine mammals and active acoustics to quantify the spatial distribution of small and large fishes. Fish distributions were examined during foraging trips of northern fur seals (Callorhinus ursinus), and initial results suggest these prey distributions may influence the diving behavior of fur seals. The Saildrone is faster, has greater instrument capacity, and requires less support services than its counterparts. This innovative platform performed well in stormy conditions, and it demonstrated the potential to augment fishery surveys and advance ecosystem research.

Abstract: Persistence of oil floating in the ocean is an important factor for evaluating hydrocarbon fluxes from natural seeps and anthropogenic releases into the environment. The objective of this work is to estimate the surface residence-time of the oil slick and to determine the importance of wind and surface currents on the trajectory and fate of the released oil. Oil slicks released from natural hydrocarbon seeps located in Green Canyon 600 lease block and its surrounding region in the Gulf of Mexico were analyzed. A Texture Classifying Neural Network Algorithm was used to delineate georectified polygons for oil slicks from 41 synthetic aperture radar images. Trajectories of the oil slicks were investigated by employing a Lagrangian particle-tracking surface oil drift model. A set of numerical simulations was performed by increasing hindcast interval in reverse time order from the image collection time in order to obtain the closest resemblance between the simulated oil pathways and the length and shape of the oil slicks observed in SAR images. The average surface residence-time predicted from the hindcast modeling was 6.4 h (± 5.7 h). Analysis of a linear regression model, including observed oil slick lengths and variables of wind, surface current, and their relative direction, indicated a statistically significant negative effect of wind speed on the surface oil drift. Higher wind speed (> 7 m s-1) reduced length of the oil slicks. When wind and surface currents were driving forces of the surface oil drift model, a good agreement between simulated trajectories and subsequent satellite observations (R2 = 0.9) suggested that a wind scaling coefficient of 0.035 and a wind deflection angle of 20º to the right of the wind direction were acceptable approximations for modeling wind effects in this study. Results from the numerical experimentation were supported by in situ observations conducted by a wind-powered autonomous surface vehicle (Saildrone). Results indicated that the surface currents are, indeed, responsible for stretching oil slicks and that surface winds are largely responsible for the disappearance of the oil slicks from the sea surface. Under conditions of low wind and strong current, natural seeps can produce oil slicks that are longer than 20 km and persist for up to 48 h.

Abstract: Demonstrating the feasibility of operating the Saildrone in the northern Gulf of Mexico within a high amount of maritime activity, including commercial and recreational fishing, shipping, and oil and gas platforms and associated servicing vessels. Demonstrate the utility of “high-speed” (up to 9 knots) wind-propelled surface vehicles as fast adaptive sampling response tools and to effectively fill in gaps between moorings at separations greater than the local correlation length scales; Collect a dataset that can be used for regional ecosystem model development and for designing the observational systems needed for process studies of shelf-ocean exchange phenomena of import to the carbon cycle in the Gulf.

Abstract: During recent decades the US Arctic is experiencing a rapid loss of sea ice and subsequently increasingly warmer water temperatures. To better study this economically and culturally important marine ecosystem and the changes that are occurring, the use of new technologies is being explored to supplement traditional ship, satellite and mooring based data collection techniques. Unmanned surface vehicles (USV) are a rapidly advancing technology that has the potential to meet the requirement for long duration and economical scientific data collection with the ability for real-time data and adaptive sampling. In 2015, the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory (NOAA-PMEL), the University of Washington (UW) and Saildrone Inc. (Alameda, California) explored the use of a novel USV technology in the Bering Sea and Norton Sound. Two Saildrones, wind and solar powered unmanned surface vehicles that can be used for extended research missions in challenging environments, were equipped with a suite of meteorological and oceanographic sensors. During the >3 month mission, the vehicles each traveled over 4100 nm, successfully completing several scientific survey assignments. This mission demonstrated the capability of the Saildrone vehicle to be launched from a dock to conduct autonomous and adaptive oceanographic research in a harsh, high-latitude environment.