Enhancements to Ocean Current Measurment Technology on the Tropical Atmosphere Ocean (TAO) Array

As part of an effort to improve air-sea flux estimates in the tropical Pacific, NOAA's National Data Buoy Center (NDBC) is significantly improving its capability to monitor ocean currents within the Tropical Atmosphere Ocean (TAO) array. These additional ocean current measurements will provide an in-situ reference of satellite wind measurements and increase our scientific knowledge of the role of the near-surface and upper-ocean velocity in transporting heat, momentum and salinity in the tropical Pacific. In 2022, NDBC began a five-year TAO Recapitalization project informed by the Tropical Pacific Observing System (TPOS) 2020 final report. The newly recapitalized TAO array, or TAO Recap, will include real-time near-surface current observations at more than half of the stations and high-resolution velocity profiles to 300 meters at eight stations. The addition of this new capability within the TAO array extends beyond increasing our understanding of the science of tropical Pacific variability to also include programmatic, operational, and technical benefits. To determine the robustness of this method for collecting real-time current profile data, NDBC enhanced 8 TAO moorings with this capability. The last of these deployments was located in the core of the equatorial cold tongue at 0° 110°W. This location is situated in an especially challenging region known for buoy vandalism, heavy biofouling, and fish interference. The results indicate high agreement between the profile and point-source data, with most errors within ±5.0 cm/s. In addition, there was limited evidence of signal interference from fish and other sensors. Based on these results, we conclude that our measurement strategy is robust, and it will provide valuable real-time current profiles that will greatly improve our understanding of the air-sea fluxes, satellite wind measurements, and the variability of the tropical Pacific.