MOTIVE
Studying Mixing Below Tropical Instability Waves
MOTIVE: Mixing belOw Tropical Instability waVEs
Using a combination of yearlong moored observations and two dedicated cruises in 2024 and 2025 scientists will collect data at TIW fronts that will help us better understand internal wave dynamics associated with the fronts and how they may lead to ocean turbulence and the turbulent transport of heat within the ocean. Last year, the science team deployed the moorings and this year they will be retrieving the instruments full of a year’s worth of important data. GO-BGC deployed two floats during the deployment cruise in November 2024.
The observational campaign employs moorings, ship-mounted acoustics, ship-based profiling systems including a rapid profiling CTD. Three moorings will be recovered north of the operational 140°W Tropical Atmosphere Ocean (TAO) mooring to target the seasonal cycle in the Tropical Instability Waves (TIW) modulation of internal waves and mixing. The proposed work has important implications for understanding the El Nino Southern Oscillation (ENSO) and the role of the tropical oceans in climate.
Ship: R/V Sikuliaq
R/V Sikuliaq, pronounced [see-KOO-lee-auk], is a 261-foot oceanographic research ship capable of bringing scientists to the ice-choked waters of Alaska and the polar regions. Sikuliaq, one of the most advanced university research vessels in the world, is able to break ice up to 2.5 feet thick. Constructed at Marinette Marine Corporation, a shipyard in Marinette, Wisconsin, Sikuliaq is homeported in Seward, Alaska, at UAF’s Seward Marine Center. Cover photo by Sarah Spanos.
Dates:
November 26, to December 19, 2025
Ports:
Honolulu, Hawaii, to Papeete, Tahiti
Chief Scientist:
Caitlin Whalen, University of Washington
Transit:
After the cruise ends in Tahiti, the ship will transit south to Punta Arenas, Chile from December 22, 2025 to January 8, 2026 in order to pick up science operations from the decommissioned R/V Palmer. More floats will be deployed during that journey.
Floats to be deployed:
- BGC: 8 (6 SIO, 2 PMEL)
- Core Argo: 11 (2 SIO, 9 PMEL Core)
- NKE float: 1 (SIO)
External Blog
Follow along with Anna Deppenmeier: MOTIVE 2025 – from the Hula to the ‘ote’a 🌴🌊🛳️
MOTIVE Expedition Logs
Float Decoration
Celebrating teamwork, creativity, and a little arts-and-crafts fun before six new floats launch from R/V Sikuliaq.The six floats deployed from R/V Sikuliaq in the coming weeks will be sent overboard inside a cardboard box. That helps protect all the important sensors...