Arctic Summer Sea Ice in 3D

Arctic sea ice is diminishing with climate warming at a rate unmatched for 1000 years. As the receding ice pack changes rapidly and becomes increasingly mobile, the demand from academic and commercial stakeholders for accurate and timely sea ice forecasts is intensifying. Forecasting accuracy is enhanced with the assimilation of sea ice thickness observations from satellite altimetry. However, these data are currently unavailable during summer when they would be most valuable for stakeholders, owing to significant data processing challenges. This has been identified as a key observation gap for polar research by the IPCC.SI/3D will address this gap, harnessing deep machine learning, modelling of the radar altimeter response, and dedicated field campaigns, to overcome the processing barriers. I will integrate satellite data from multiple ESA, EU-Copernicus, and NASA altimetry missions to produce the first 15+ year high-accuracy record of pan-Arctic sea ice thickness without interruptions in the summer. With this unique dataset, I can achieve the following goals. (1) To close the Arctic sea ice volume budget, pinpointing the mechanisms driving seasonal decay and breakup of the ice pack and the feedbacks of sea ice loss on Arctic temperatures. (2) To upgrade seasonal sea ice forecasts from state-of-the-art modelling systems by assimilating summer ice thickness observations.SI/3D will create a new discipline of sea ice research by using altimetry to study the Arctic summer, which is risky. Having led the first published pilot research in this field, however, I am ideally placed to carry out the project and will leverage the expertise I have gained at three international Arctic research institutions to make it happen. On completion, this work will transform opportunities for Arctic system science, improving sea ice modelling, forecasting on timescales from weeks to years, mass budgeting, and biogeochemistry studies during the critical summer melting months.