Periodic Reporting for period 1 - SEADOG (Sea ice across Dansgaard-Oeschger events in Greenland)
Reporting period: 2015-10-01 to 2017-09-30
Sea salt sodium (Na) was the focus of this work because substantial evidence suggests that the surface of the sea ice is a significant source of sea salt to the polar regions. This raises the possibility that ice core Na may be interpreted as a tracer of past sea ice conditions. Model simulations of sea salt aerosol at various Arctic sites, produced by this project, confirm the importance of the sea ice source of sea salt aerosol. For the first time, sea salt concentrations deposited at Greenland ice core sites were calculated using a global process-based model. Simulated values compared well with monthly-resolved ice core chemistry records. Based on tests conducted, we conclude that the influence of sea ice extent on year-to-year changes in Greenland ice core sea salt concentrations is minimal under present-day Arctic conditions. The majority of ice core sea salt variation is due to meteorological factors. However, ice cores from the High Arctic, away from central Greenland, offer promise for sea ice reconstruction.
Adaption of atmospheric chemistry transport models for simulations of D-O events under Last Glacial climatic conditions is still ongoing.
To test what controls the year-to-year variability in sea salt recorded in Arctic ice cores, I performed simple sensitivity tests to compare the influence of sea ice changes versus changes in meteorology i.e. temperature, wind strength. Results suggests that while meteorology is the dominant control on Greenland ice core sea salt signals, ice core records from the High Arctic are more likely to be influenced by sea ice conditions.
A peer-reviewed article detailing the development of Greenland ice core sea salt modelling capability was published in the journal Atmospheric Chemistry and Physics. A second manuscript presenting examining controls on Arctic ice core sea salt variability is undergoing final edits prior to submission. I have presented results from this project at the international PAGES Open Science Meeting (2017) and through invited talks at the UK Paleoclimate Climate Society meeting (2017) and University of Copenhagen (2017). Co-authored studies, including work to simulate the sea ice and climate change across D-O events, have also been presented at international conferences.