December PI Spotlight: Dr. Libe Washburn

Dr. Libe Washburn

Oceanographer and Emeritus Professor 
Marine Science Institute (Director) and the Department of Geography, University of California, Santa Barbara (UCSB)
libe.washburn@ucsb.edu

Ocean Observing Tools: High-Frequency Radar (HFR), Aerial Drones, Autonomous Surface Vehicles (ASVs)

Published December 11, 2024 by Makenna Martin

“SCCOOS has provided opportunities for colleagues and me to participate in ocean observing activities that directly benefit society including US Coast Guard Search and Rescue Operations and Oil Spill response.”

         SCCOOS PI, and Chair of the SCCOOS Board of Governors, Dr. Libe Washburn, is an Oceanographer and Emeritus Professor in the Marine Science Institute and Department of Geography at UC Santa Barbara. SCCOOS is lucky to partner with Dr. Washburn, one of the pioneering scientists behind the application of High-Frequency Radar (HFR) technology to coastal oceanography that enables researchers to track the ocean’s surface currents in near-real time. HFR antennas are placed along the coastline to measure how radio waves reflect off the ocean’s surface; the behavior of the reflected radio waves tells us the speed and direction of ocean surface currents in near real-time.

Image: Diagram of HFR antenna (left) and how radio wave pulses are transmitted and received to detect ocean current direction and speed (figure adapted from the Coastal Ocean Currents Monitoring Program)

          The ability to track where and how quickly coastal ocean water is moving is essential for many important community services, including: assessing and mitigating impacts of impaired water quality (e.g., monitoring pollution sources or Harmful Algal Blooms), tracking oil spills, assisting in search and rescue efforts, and monitoring the physical aspects of the ocean environment to help understand ecosystem change. SCCOOS supports 31 HFR stations in Southern California that are operated and maintained by Washburn’s research group at UCSB and colleagues at California Polytechnic State University, San Luis Obispo, University of Southern California, and Scripps Institution of Oceanography. This is complemented by an array of HFRs in Central and Northern California, managed by CeNCOOS.

Images: HFR antenna along the coast at the Scripps Institution of Oceanography (Image from US IOOS); Map of SCCOOS and CeNCOOS HFR locations along the coast of California.

        Dr. Washburn explains, “in oceanography I have always focused a portion of my research on applied issues such as ocean pollution.” HFR data have many useful applications, but these radar systems are particularly vital to response and mitigation efforts when pollutants are released or spilled into the ocean. As such, Dr. Washburn’s and colleagues' HFR data have become vital to the County of San Diego Department of Environmental Health and the California Department of Fish and Wildlife (CDFW) Office of Spill Prevention and Response (OSPR). 

        One example of HFR use is in responding to the Tijuana River sewage plume in San Diego, California. The plume is an intensifying public health threat where untreated sewage from Tijuana, Mexico, flows into coastal waters and moves northward to San Diego. The bacteria and viruses in this waste can harm beachgoers and coastal workers, so tracking the sewage plume is vital to public health. “HFR-derived surface currents data are used daily by the County of San Diego, to help inform decisions on when water quality issues originating from Mexico may be impacting our beaches” CDFW OSPR. These data help coastal managers make decisions about beach closures for public safety.

Images: Aerial view of the Tijuana Sewage Plume (photo from Heyn et al., 2008); Beach closure signs in San Diego’s Imperial Beach due to sewage-contaminated water (photo by Gregory Bull/AP)

          HFR is also critical technology for oil spills, notably during the 2015 Refugio Oil Spill near Santa Barbara, where 100,000 gallons of crude oil was spilled from a broken pipeline onto  Refugio State Beach. This spill had demonstrable, harmful effects on the local ecosystem with oil spreading to nearby beaches, requiring rescue of stranded oil-covered seabirds and marine mammals. CDFW OSPR and SCCOOS researchers were able to install a temporary, solar-powered  HFR site within 24 hours of the start of the spill to increase local coverage of the spill and track where the oil would be most likely to move. The real-time oceanic current information was used by State and Federal emergency responders to optimize the spill response to protect the most critical habitats and resources. After the initial oil spill response, the HFR surface current data were used for post-spill resource and habitat damage assessment. 

Images: Refugio oil spill on Santa Barbara beaches (Image from US Coast Guard); Brown Pelican covered in oil, rescued by CDFW (Image from ABC news)

          “The Office of Spill Prevention and Response (OSPR) has benefited greatly from its partnership with SCCOOS and CeNCOOS” reports the Office of Spill Prevention and Response. “HFR technology has proven extremely useful in oil spill response. These data aid OSPR greatly in our responsibility to effectively address human, habitat, and wildlife concerns during an oil spill response. The products are [...] an invaluable utility that we use nearly daily and extensively during the 2015 Refugio Beach oil pipeline spill and the 2021 Pipeline spill in Orange and San Diego Counties.” 

Images: Workers remove oil-covered rocks from beaches during the Refugio oil spill; Workers at the Refugio site with equipment used to help contain spills (Photos from CDFW OSPR)

          In addition to helping develop the HFR technology, Dr. Washburn’s lab also develops other ocean-observing tools, conducting research that involves both, “basic ocean science and related technology development.” His lab designs and builds instruments to facilitate rapid, low-cost data collection. For example, using aerial drones to collect sample seawater, an autonomous standup paddleboard to measure subsurface currents, and a smaller autonomous Boogie Board used to calibrate HFR antennas at sites where flying aerial drones is prohibited. These autonomous instruments were designed and built by lab member, Eduardo Romero. For more information on these projects, see the Washburn Lab website.

To learn more about the HFR and surface current data, see the SCCOOS HFR project page, and the HFR data portal. 

Keep an eye out for next month's SCCOOS Spotlight to learn about another of our PIs and community stakeholders!