Project: Repeat Observations by Gliders in the Equatorial Region

Description from NSF award abstract:
The objectives of this project are to quantify the variability in the position and strength of the Pacific Equatorial Front and Equatorial Undercurrent (EUC), and the partitioning of flow around the Galapagos Archipelago. The field work will consist of three sustained high-resolution glider transects to assess variability of the Equatorial Current System, including the obstruction of the EUC by the Galapagos Archipelago. A section at 93W will be representative of the EUC and equatorial front to the west of the Archipelago, and two sections connecting the northern and southern ends of this section to the Archipelago will quantify how the EUC is partitioned into pathways. Using four gliders, each section will be repeated every 10 days, thus barely resolving tropical instability wave variability at a period of 20 days. Spray gliders equipped with CTD and ADPs will profile to 500 m every 3 hours, covering 3 km during the dive cycle. Scientific analyses, including the interpretation of the observations using a new high-resolution model, will focus on quantifying the temporal evolution on scales from seasons to weeks in the Equatorial Current System down to horizontal scales of 10 km. Estimates will be made of horizontal fluxes of mass, heat, and salt. The pathway of the EUC will be determined. Observations will be compared and analyzed with a hierarchy of extant numerical models of the Equatorial Current System and an ongoing data assimilation analysis of the Equatorial Pacific.