Upper Ocean Currents in the Tropical Pacific as Measured from Saildrone Uncrewed Surface Vehicle in Comparison to Surface and Subsurface Moorings at 0, 140W

Uncrewed Surface Vehicles (USV) by Saildrone, Inc. (referred to as saildrones), with their ability to measure multiple Essential Ocean Variables, have the potential to significantly enhance the capabilities of the Tropical Pacific Observing System (TPOS). This project aims to compare the saildrone Acoustic Doppler Current Profiler (ADCP) measurements against 0, 140W moored TPOS ADCP and current meter datasets. Differences in these intercomparisons are interpreted in terms of horizontal and vertical shears, biases caused by the presence of fish, platform motion, and noise in the measurement. The five TPOS missions since 2017 have involved 14 saildrone USV, all of which have included ADCP observations. These data provide several lessons for resolving near-surface mesoscale and submesoscale currents, including circulations associated with equatorial upwelling. Potential strategies for observing these upper ocean current features will be discussed.