Abstract:

Sea ice, or frozen seawater, significantly influences polar ocean dynamics – acting as a primary control mechanism for atmospheric-oceanic heat exchange and affecting the rate at which ice shelves disintegrate. At its maximum extent, sea ice covers up to 7% of the Earth’s surface, or 10% of the global ocean surface. While changes in sea ice are primarily driven by seasonality, extratropical cyclones drive short-term (near-daily) changes. However, there is a limited understanding of the changes to sea ice caused by extratropical cyclones – primarily due to observational constraints. 

Additionally, sea ice is not uniform; it varies in its material and roughness characteristics. In polar regions, optical sensors are hindered by persistent cloud cover and periods of varying solar illumination – making the use of synthetic aperture radar (SAR) essential. However, the effects of material and roughness are difficult to disentangle using a single SAR sensor. 

In this thesis, I use remotely-sensed data products to describe the characteristics and near-daily changes in sea ice. In Chapter 1, I develop a framework for observing the interaction between extratropical cyclones and sea ice in the Southern Ocean. In Chapter 2, I utilize two different SAR sensors to better characterize material and roughness variations of sea ice. This work advances the understanding of short-term changes in sea ice and provides a more accurate representation of sea ice for understanding polar ocean dynamics