Glacier and glacier lake surface elevation change monitoring using SWOT

Principle Investigator: Thorsten Seehaus (Friedrich-Alexander-Universität Erlangen-Nürnberg Institute of Geography)

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This project is dedicated to integrating SWOT satellite data into ongoing glaciological analyses globally. The primary focus is on leveraging SWOT's capabilities to enhance our understanding of surface elevation changes in mountain glaciers, and polar ice caps, and monitoring supra-glacial and pro-glacial lakes.

In the context of monitoring glacier surface elevation changes, the project aims to evaluate the applicability of SWOT data. Optical and Synthetic Aperture Radar (SAR) remote sensing as well as altimetry techniques are pivotal for this endeavor, however underlay specific limitations, like cloud cover and daylight dependency for optical sensors, signal penetration and topographic layover, and shadow effects for SAR data, sparse point measurements for altimeter.

SWOT emerges as a promising tool to overcome certain limitations. Its steep viewing angle minimizes topographic effects in mountainous terrain, reducing layover, shadowing, and foreshortening. The KaRIn instrument's higher SAR frequency limits radar signal penetration issues on glacier surfaces compared to TanDEM-X. SWOT's swath acquisition technique allows extended surface elevation measurements, limiting the need for spatial interpolation as compared to altimeter point measurements.

The project's second objective focuses on investigating the suitability of SWOT for monitoring supra-glacial lakes in Greenland. These lakes, integral to Greenland Ice Sheet dynamics, form due to seasonal ice melt. SWOT will allow precise water surface elevation measurements, providing a unique opportunity to monitor changes in supra-glacial lake dynamics. Integrating SWOT data with optical and SAR imagery enhances accuracy in lake volume assessments and aids in understanding their impact on ice melt and runoff.

Lastly, the project aims to evaluate SWOT's performance in monitoring newly formed pro-glacial lakes in the Tropical Andes. Pro-glacier lakes, formed at glacier termini, pose a high risk to downstream areas by glacial lake outburst floods (GLOFs). Thus we aim to evaluate SWOT's effectiveness in mapping and assessing these lakes, especially for water bodies not covered by existing inventories. Integration with ground truth measurements and ongoing monitoring systems will provide valuable insights into the response of glacier-fed lakes to changing climatic conditions.