Amundsen Sea sea-ice variability, atmospheric circulation, and spatial variations in snow isotopic composition from new West Antarctic firn cores

• Main Author: Criscitiello, Alison S.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 2014
• Subjects: Ocean-atmosphere interaction; Sea ice; Antarctic; West Antarctica; Amundsen Sea; West Antarctic Ice Sheet; Pacific; Island Bay; Pine Island Bay; Antarc*; Antarctica; Ice Sheet; Pine Island
• Online Access: https://hdl.handle.net/1912/6402

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2014 Recent work has documented dramatic changes in the West Antarctic Ice Sheet (WAIS) over the past 30 years (e.g., mass loss, glacier acceleration, surface warming) due largely to the influence of the marine environment. WAIS is particularly vulnerable to largescale atmospheric dynamics that remotely influence the transport of marine aerosols to the ice sheet. Understanding seasonal- to decadal-scale changes in the marine influence on WAIS (particularly sea-ice concentration) is vital to our ability to predict future change. In this thesis, I develop tools that enable us to reconstruct the source and transport variability of marine aerosols to West Antarctica in the past. I validate new firn-core sea-ice proxies over the satellite era; results indicate that firn-core glaciochemical records from this dynamic region may provide a proxy for reconstructing Amundsen Sea and Pine Island Bay polynya variability prior to the satellite era. I next investigate the remote influence of tropical Pacific variability on marine aerosol transport to West Antarctica. Results illustrate that both source and transport of marine aerosols to West Antarctica are controlled by remote atmospheric forcing, linking local dynamics (e.g., katabatic winds) with large-scale teleconnections to the tropics (e.g., Rossby waves). Oxygen isotope records allow me to further investigate the relationship between West Antarctic firn-core records and temperature, precipitation origin, sea-ice variability, and large-scale atmospheric circulation. I show that the tropical Pacific remotely influences the source and transport of the isotopic signal to the coastal ice sheet. The regional firn-core array reveals a spatially varying response to remote tropical Pacific forcing. Finally, I investigate longer-term (~200 year) ocean and ice-sheet changes using the ...