In this seminar Nikolas Olson Aksamit, Associate Professor in Applied Math and Earth Systems Analysis at UiT, will talk about a new approach to study sea ice defromation from drifters:
Sea ice drift and deformation, namely sea ice dynamics, play a significant role in atmosphere–ice–ocean coupling. Deformation patterns in sea ice can be observed over a wide range of spatial and temporal scales, though high-resolution objective quantification of these features remains difficult. Previous studies have used both displacement grids and sea ice buoy trajectories to quantify observations of sea ice deformation, both in single time slices and over time. I will focus in this talk on identifying Lagrangian coherent structures (LCS), that is, using diagnostics that assess flow patterns and features that maintain a consistent behavior over a given window of time. We will compare typical LCS methods with newly derived single-trajectory stretching measures, the trajectory-stretching exponents (TSEs). Our work expands on previous ocean current studies that have shown TSEs provide an approximation of Lagrangian coherent structure diagnostics when only sparse trajectory data are available. As TSEs do not require multiple buoys, we find they have an expanded range of use when compared with traditional Eulerian buoy-array deformation metrics and provide local-stretching information below the length scales possible when averaging over buoy arrays. We hope that this new approach will help the community better understand sea ice dynamics by allowing deformation analysis of a much greater range of drift products.
The seminar will take place at the Earth Observation/CIRFA common space and online on Thursday 4 May at 14:00. Welcome!