Adding a real-time current profile to NDBC TAO moorings for enhanced ocean boundary layer observations

A known characteristic of the Tropical Pacific is the interaction between the zonal winds and the equatorial thermocline, which allows coupled variability like ENSO to evolve. However, this fundamental feedback is the least understood and most poorly modeled element of the tropical climate system. To increase our knowledge of the mechanisms controlling this feedback process, NOAA's National Data Buoy Center (NDBC) and Pacific Marine Environmental Laboratory (PMEL) have collaborated on a joint project to enhance operational NDBC Tropical Atmosphere Ocean (TAO) moorings. The four-year project is part of a larger internationally coordinated effort, TPOS 2020, to refine components of the Tropical Pacific Observing System. The goal of this project is to develop the methodologies to better resolve near surface stratification in real-time to support operational climate forecasting and ENSO research. To this end, eight TAO moorings, in regimes that span the phenomena of the mixed layer processes in the tropical Pacific, will be upgraded with new capabilities and added value. Some of these new capabilities include a real-time current profile for the upper 70 meters, and enhanced vertical resolution of the temperature-salinity structures in the upper 50 meters. To easily integrate these new measurements into the existing array, each enhanced station is deployed with a secondary data acquisition payload, the Self Contained Ocean Observing Payload (SCOOP). The SCOOP payload communicates with the subsurface instruments through an augmentation to the inductive technology. This augmentation implemented by NDBC allows numerous payloads or buoy controllers to share a single inductive communication loop. The initial results indicate this is a robust method for collecting real-time current profile data, with a data return of almost 100% and minor signal interference from fish and other sensors.