Initial work focused on modifying the chemical transport model in order to simulate the sea salt aerosol budget at Arctic sampling locations. To achieve this, the sea ice source of sea salt was required in addition to the open ocean source. I also found that some sea salt emissions were required from the thick, multi-year sea ice, as well as the thinner sea ice that re-forms annually. The next step was to include capability to simulate concentrations of sea salt deposited on the ice sheet to allow direct comparison with the ice core record. Using the optimised chemical transport model, Greenland ice core sea salt concentrations can be simulated to within a factor of two and the seasonal cycle, with maximum sea salt in winter, is well-captured. Model simulations suggest that the sea ice source contributes relatively little sea salt to central Greenland ice cores under present-day conditions. In contrast, simulation suggest that more than 75% of the sea salt found in ice cores from the High Arctic, located closer to the sea ice pack, originates from the sea ice surface. Furthermore, the model simulations captured up to 60% of the year-to-year variability in sea salt concentrations in some Greenland ice cores.
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.
