Jó et al. (2025) Surface Velocity and Dynamics of the Southern Patagonian Icefield Using Feature and Speckle Tracking Methods on Sentinel-1 SAR Images During 2019–2020

Identification

• Journal: Remote Sensing
• Year: 2025
• Date: 2025-11-18
• Authors: Viviána Jó, Tamás Telbisz, Ádám Ignéczi, Maximillian Van Wyk de Vries, Sebastián Pereira, László Mari, Balázs Nagy
• DOI: 10.3390/rs17223742

Research Groups

• Department of Physical Geography, Eötvös Loránd University, Budapest, Hungary
• PermaChile Network, Globe Foundation, Budapest, Hungary
• School of Geographical Sciences, University of Bristol, Bristol, UK
• Complex and Multihazard Research Group (CoMHaz), Department of Earth Sciences, University of Cambridge, Cambridge, UK
• Complex and Multihazard Research Group (CoMHaz), Department of Geography, University of Cambridge, Cambridge, UK
• DIHA, Pontificia Universidad Católica de Chile, Santiago, Chile

Short Summary

This study investigated the surface velocity and dynamics of 64 glaciers in the Southern Patagonian Icefield (SPI) during 2019–2020 using Sentinel-1 SAR images, revealing an unstable and rapidly changing state primarily influenced by calving events.

Objective

• To understand the current state of the Southern Patagonian Icefield (SPI) and explore the dynamic restructuring of its glaciers by investigating surface velocity changes and their connection to overall glacier dynamics and ice-loss processes, particularly near termini where acceleration can indicate drastic ice thinning and calving.

Study Configuration

• Spatial Scale: Southern Patagonian Icefield (SPI), covering an area of 13,000 square kilometers, with 64 individual glaciers studied. Velocity measurements were taken in 846 one-square-kilometer (1 km²) sample areas.
• Temporal Scale: 8 July 2019 to 10 November 2020 (a 418-day study period). Repeat image pairs were collected 12 days apart.

Methodology and Data

• Models used:
  • Feature tracking and Speckle tracking methods (using an algorithm developed by Tuckett et al., 2019).
  • GMTSAR for image co-location and transformation.
  • MATLAB PIVSuite for cross-correlation to estimate displacement.
  • ArcGIS 10 software for Digital Terrain Model (DTM) analysis (slope, aspect, elevation).
• Data sources:
  • Sentinel-1a and 1b Interferometric Wide Swath mode Single-Look Complex Synthetic Aperture Radar (SAR) amplitude images.
  • Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) for transforming velocity from radar to map coordinates.
  • SRTM 30 meter (m) resolution topography model for topographic parameter analysis.
  • Randolph Glacier Inventory version 6.0 for glacier outlines and names.
  • Ice thickness data from Millan et al. (2022) and Davis (2002).

Main Results

• A total of 450 velocity maps were generated, with successful measurements in 66% of the 846 sample areas across 64 glaciers.
• Glacier surface velocity ranged from 0 to 0.0002082 meters per second (m/s) (6571 meters per year) over the study period.
• The fastest overall movement was observed on 16 November 2019, with an average velocity exceeding 0.0000214 m/s (676 meters per year).
• Topographic parameters (elevation, slope, aspect) showed variable correlation with mean velocity, with a strong negative correlation (-0.964) between velocity and increasing elevation observed for Viedma Glacier. Mean ice thickness did not show a strong correlation with velocity.
• Glaciers were classified into four velocity profile types: increasing (20%), decreasing (6%), single-peak (37.5%), and multiple-peak (36%). Larger glaciers generally exhibited more complex, multiple-peak velocity profiles.
• The Penguin Glacier was identified as the fastest, reaching 0.0002057 m/s (6491 meters per year), while SPI119 was the slowest, with a maximum velocity of 0.00000265 m/s (83.6 meters per year).
• Approximately 30% (19) of the studied glaciers showed acceleration near their termini, predominantly tidewater glaciers, indicating a significant impact of calving.
• Pío XI Glacier experienced a strong acceleration exceeding 0.0000950 m/s (3000 meters per year) from early August to early November 2019, attributed to a massive calving event.
• Jorge Montt Glacier showed continuous rapid movement near its terminus (over 0.0000950–0.0001267 m/s in periods), but a drastic slowdown to 0.00000634 m/s (200 meters per year) at 13–14 kilometers from the terminus, contrasting previous studies that reported acceleration in this area.
• Upsala Glacier exhibited dynamic rearrangement and a slowdown compared to earlier observations. Moreno Glacier showed relative stability in its dynamics over a decade.

Contributions

• Provides a comprehensive, high-resolution assessment of glacier surface velocity and dynamics across the entire Southern Patagonian Icefield (SPI) for a recent period (2019–2020) using Sentinel-1 SAR imagery.
• Identifies and classifies four distinct glacier velocity profile types, demonstrating that larger glaciers tend to exhibit more complex, multiple-peak velocity patterns.
• Quantifies the significant and often fluctuating impact of calving on glacier terminus velocity, particularly for tidewater glaciers, and highlights specific, dramatic acceleration events (e.g., Pío XI).
• Reveals notable dynamic changes and potential slowdowns in several major glaciers (e.g., Jorge Montt, Upsala) compared to previous long-term studies, suggesting an unstable state of the SPI.
• Offers crucial insights for understanding the ongoing changes and future trajectory of the SPI, which is vital for regional water resource management and natural hazard assessment.

Funding

• National Research, Development and Innovation Office, Hungary (Grants NKFIH OTKA K147424)
• Tempus Public Foundation, Erasmus+ grant 2022-1-HU01-KA131-HED-000054740 (V.J.)
• Tempus Public Foundation, Erasmus+ grant 22-1-KA131-000054740-STT605 (B.N.)

Citation

@article{Jó2025Surface,
  author = {Jó, Viviána and Telbisz, Tamás and Ignéczi, Ádám and Vries, Maximillian Van Wyk de and Pereira, Sebastián and Mari, László and Nagy, Balázs},
  title = {Surface Velocity and Dynamics of the Southern Patagonian Icefield Using Feature and Speckle Tracking Methods on Sentinel-1 SAR Images During 2019–2020},
  journal = {Remote Sensing},
  year = {2025},
  doi = {10.3390/rs17223742},
  url = {https://doi.org/10.3390/rs17223742}
}