2018-2019 USAP Field Season
BAS Thwaites Moorings
Dr. Adrian Jenkins
Supporting Stations: RV/IB Nathaniel B. Palmer
The oceanographic moorings in the eastern Amundsen Sea were originally deployed as part of the UK iSTAR (ice sheet stability) program. Some of these moorings have now been continued as part of the NERC-funded project Ocean Forcing of Ice-Sheet Change, funded through 2023. These moorings are also considered a supporting dataset for the International Thwaites Glacier Collaboration (ITGC), and are particularly relevant to the MELT and TARSAN projects.
Originally, 9 moorings were deployed in 2012; 7 of these were recovered in 2014, with one lost and one not releasing. Five moorings were redeployed in 2014, and four of these were redeployed from RV Araon in 2016; the ship was unable to reach the fifth because of ice conditions. In 2018, an attempt was made to recover the five moorings on RV Araon, but because of severe ice conditions and time constraints resulting from a medevac, none were recovered. At present there are five moorings deployed; one has been in the water since 2014, and four have been deployed since 2016.
From the project description on the BAS website:
"Our ambition for this project is to use our long-term in situ measurements of ocean-heat delivery to understand the major drivers of ice loss in some of the most rapidly retreating parts of the Antarctic ice sheet. The outcome from this research will inform projections for future ice-sheet stability and global sea-level projections.
"Our aims are to understand how ocean heat influences changes to Antarctic ice, and to reduce uncertainty in scientific predictions for a future world and to provide Government with scientific assessment of how these issues will affect the everyday lives of people in decades to come. This project is key component of a major UK/US collaboration that will take place over the next 5-years [ITGC].
"We use oceanographic moorings and bespoke radar systems to create a unique dataset that records the major driver of Antarctic ice loss."
Field Season Overview
We hope to recover and redeploy at least two of these moorings during NBP19-02; if time and weather permits, any further mooring sites visited during the cruise would be a further benefit to ITGC.
The first priority for the cruise is the mid-shelf mooring (in the trough leading to PIG and Thwaites); this has now been deployed for five years, and this is likely the last chance to recover it before the release batteries run out. Second on the list of priorities are the two moorings near Pine Island Glacier; the southernmost mooring has a unique, continuous time series since 2009. The easternmost mooring near the shelf break is probably close to the ship's route to and from the Amundsen Sea, so might not require much of a diversion. The western shelf mooring is, however, likely to be somewhat out of the way. A full list of positions is attached to this SIP.
Deploying Team Members