Recovered ADCP instrument. Photo by Nicole Hoban, NDBC.
The efficient deployment and success of the real-time data return system was a marked success by Karen Grissom and the team at NDBC. Velocity data was returned in real time at most of the sites, and the original five-site scope of the project was expanded to nine separate sites via efficient use of instrumentation and shiptime. Analysis of the velocity data was underway as early as 2018, when most of the instruments were still in the water.
This analysis has revealed a wide geographic scope for systematic deep diurnal jets, which directly connect wind forcing to the interior ocean below the mixed layer, and appear to deepen with stronger wind forcing (Masich et al., 2021). Robust, high-resolution velocity records at each site provide ample data for exploring the effect of fronts on the Ekman response and for describing the near-surface Ekman divergence off the equator, both of which are underway. We have also identified opportunities to explore barrier layer dynamics, the near-surface response to Westerly Wind Bursts, and the reversing jet phenomenon via this and possible future deployments of this type of instrumentation.
1. This type of deployment yielded useable real-time data for the majority of the deployment duration at nearly all of the sites across the tropical Pacific, and could thus be used to resolve a number of important near-surface phenomena of interest to TPOS stakeholders in real time.
2. To resolve diurnal and subdiurnal processes, a less conservative sampling scheme must be employed than the current 2 to 6 mins of recording per hour.
3. To estimate the influence of wind on tropical Pacific dynamics via systematic deep diurnal jets, deployments of this type should focus on the eastern equatorial Pacific.
Masich, J., W.S. Kessler, M.F. Cronin, K. R. Grissom. Diurnal cycles of near-surface currents across the tropical Pacific. JGR-Oceans. 2021.
Velocity data can be found at: https://www.pmel.noaa.gov/ocs/ndbc-tpos-mooring-enhancement-pilot-project
All other data (temperature, salinity, meteorological) can be found at: https://www.pmel.noaa.gov/tao/drupal/disdel/