Time variability on turbulent mixing of heat around melting ice in the West Antarctic

Alexander Brearley, British Antarctic Survey, Prof Alberto Naveira-Garabato, Hugh Venables, Kate Hendry, Michael Meredith, British Antarctic Survey
Rationale: 

The West Antarctic Peninsula is a highly dynamic region that has undergone significant changes in atmospheric temperature, sea ice and glacial ice over the past 40 years. Much of this variability is driven by the ocean, where large volumes of warm Circumpolar Deep Water intrude onto the shelves and are modified by mixing processes prior to reaching marine-terminating glaciers and ice shelves at the coast. Quantifying and understanding the mechanisms behind these processes is key to understanding the heat budget of the WAP and its sensitivity to future atmospheric and ocean forcing. Using a range of datasets, this project will seek to answer:

1.    What is the temporal variability in turbulent mixing and heat fluxes on the West Antarctic Peninsula?

2.    What are the key controls on this variability, including the role of winds, tides, sea ice and topography?

3.    How is this variability linked to broader scale atmospheric and ocean circulation, including Southern Annual Mode/El Nino Southern Oscillation etc.?

Methodology: 

The project will use three key datasets:

  1. Novel ocean hydrographic glider data collected in 2019-20 from Marguerite Bay, around the BAS base at Rothera, including temperature, salinity, microstructure and bio-optical parameters;
  2. 21 years of weekly/bi-weekly temperature, salinity and pressure data from the Rothera time series;
  3. Two years of data from a mooring deployed at the mouth of Ryder Bay (close to Rothera), including temperature, salinity, finescale velocity, and turbulent dissipation rate from a structure function Acoustic Doppler Current Profiler (ADCP).

The project will use the above datasets, collected between 2019 and 2022, in conjunction with both local and global atmospheric datasets to elucidate the key controls on mixing and the implications for the heat budget of the peninsula.

Location: 
British Antarctic Survey
Training: 

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at British Antarctic Survey. Specific training will

include:

  1. The potential opportunity to participate in polar research cruises in the Southern Ocean, giving experience in the collection and processing of a variety of different physical oceanographic data. Note this is not required for successful completion of the PhD as the data are already collected.
  2. Training in the piloting of and processing of ocean glider data.
  3. Training in the processing and interpretation of microstructure data, and in time series analysis techniques.
Eligibility & Funding Details: 

Please see https://inspire-dtp.ac.uk/how-apply for details.

 

Background Reading: 

Scott, Ryan M., Brearley, J. Alexander , Naveira Garabato, Alberto C., Venables, Hugh J., Meredith, Michael P.. (2021) Rates and mechanisms of turbulent mixing in a coastal embayment of the West Antarctic Peninsula. Journal of Geophysical Research: Oceans, 126. 26 pp. 10.1029/2020JC016861

Brearley, J. Alexander, Meredith, Michael P. , Naveira Garabato, Alberto C., Venables, Hugh J., Inall, Mark E.. (2017) Controls on turbulent mixing on the West Antarctic Peninsula shelf. Deep Sea Research II: Topical Studies in Oceanography, 139. 18-30. 10.1016/j.dsr2.2017.02.011

Venables, Hugh J., Meredith, Michael P., Brearley, J. Alexander . (2017) Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows. Deep Sea Research II: Topical Studies in Oceanography, 139. 9-17. 10.1016/j.dsr2.2016.09.005