57A037
High-resolution monitoring of sea-ice drift and deformation with SAR satellite data
Thomas Hollands, Wolfgang Dierking
Corresponding author: Thomas Hollands – thomas.hollands@awi.de
Most methods monitoring sea-ice drift and deformation with SAR satellite data generate motion fields at a resolution at about 1 km or coarser. However, for an expanded understanding of sea-ice processes and their motion/deformation energy balances it would be an asset to retrieve motion data at higher spatial and temporal resolution. Most recent approaches are based on the identification of corresponding patterns in temporal consecutive datasets, assuming temporal pattern stability/constancy. The position difference between corresponding patterns is taken as the drift vector, presuming a constant direction and magnitude of motion over time. Since the algorithm depends on the identifiability of corresponding patterns, one aspect of this work focuses on the comparison of miscellaneous SAR products and their performance as to sea ice. Existing products cover various polarizations and multiple radar frequency bands (L-, C- and X-band) which differ in their penetration depth and, hence, in their radar signature. Based on a comparison of algorithm performance the most suitable data product for the implemented method is identified. Deformation processes change existing patterns and thereby hurt the ‘constancy constraint’. To minimize this effect it is necessary to increase the temporal resolution depending on the existing forces within the relevant region. One option to improve the temporal resolution is to employ wide swath data, covering larger regions at coarser spatial resolution. Thus it is important to understand how characteristics of sea-ice drift change between different spatial resolutions. In the frame of this work drift patterns derived from a number of SAR imaging modes at different resolutions are compared with one another. Any difference between drift parameters obtained for different imaging modes is not only important for the portability of estimated drift fields between different resolutions, but as well an important aspect for the comparison of estimated values with simulated drift patterns from existing sea-ice models. Calculated motion fields and identified discontinuities (missing pattern correspondence) are used to delineate deformation patterns and classify them. We will report on the recent status of the work, present examples of ice velocity fields derived from different SAR imaging modes and discuss pros and cons of the investigated imaging modes.
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