Tracking the grounding line migration at Getz Ice Shelf using Sentinel-1 A/B observations

The grounding line defines the boundary of grounded ice of marine ice sheets in Greenland and Antarctica. The speed and extent of grounding line retreat indicate ice sheet stability, making tracking and quantifying grounding line migration imperative. Although satellite observations of several key glaciers and ice streams in these regions have enabled spatially dense grounding line mappings, the revisit frequency of current missions is inadequate to capture the tide-induced grounding line migration. Moreover, limited tide information due to insufficient observations and the coarse resolution of tide models near the grounding line makes it challenging to correlate tide levels to the grounding line position.

Here, we focus on observing and quantifying solely the grounding line movement at the different time scales without using tide models and taking advantage of the dense time series of Sentinel-1 SAR data acquisitions of the Antarctic Ice Sheet margins. We generated double difference interferograms with all available and coherent 6-day Sentinel-1 triplets in 2015-2024. The interferograms were generated with the custom processing chain developed at the Remote Sensing Technology Institute of the German Aerospace Center (Muir, 2020). The grounding lines were automatically delineated in the DInSAR phase using our deep neural network-based delineation pipeline, as detailed in Ramanath Tarekere et al., 2024. The Getz Ice Shelf is coherently captured in most Sentinel-1 acquisitions, making it an ideal region to test our algorithm. We will develop a statistical method to measure the spatial variation of the lines and identify stationary and non-stationary regions. Additionally, in the non-stationary regions, we will decompose the time series into seasonal and trend components, possibly discriminating long-term climate-induced grounding line retreat and variations in grounding line positions caused by different ocean tide levels.

 

References

Muir, A. (2020). System specification document for the antarctic ice sheet cci project of esa’s climate change initiative,
version 1.0. https://climate.esa.int/media/documents/ST-UL-ESA-AISCCI-SSD-001-v1.1.pdf

 

Ramanath Tarekere, S., Krieger, L., Floricioiu, D., & Heidler, K. (2024). Deep learning based automatic grounding line
delineation in DInSAR interferograms [Preprint]. EGUsphere, 2024, 1–35. https://doi.org/10.5194/egusphere-2024-223