Automated Detection of Retrogressive Thaw Slumps in the High Arctic Using High-Resolution Satellite Imagery

Retrogressive thaw slumps (RTS) are considered one of the most dynamic permafrost disturbance features in the Arctic. Sub-meter resolution multispectral imagery acquired by very high spatial resolution (VHSR) commercial satellite sensors offer unique capacities in capturing the morphological dynamic...

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Bibliographic Details
Published in:Remote Sensing
Main Authors: Chandi Witharana, Mahendra R. Udawalpola, Anna K. Liljedahl, Melissa K. Ward Jones, Benjamin M. Jones, Amit Hasan, Durga Joshi, Elias Manos
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2022
Subjects:
Arctic
permafrost
retrogressive thaw slump
satellite images
deep learning
Science
Q
Axel Heiberg Island
Canada
Ellesmere Island
Heiberg
Banks Island
Online Access:https://doi.org/10.3390/rs14174132
https://doaj.org/article/e677cc35a9ed43499a6f782fbdc11b8c
Description
Summary:Retrogressive thaw slumps (RTS) are considered one of the most dynamic permafrost disturbance features in the Arctic. Sub-meter resolution multispectral imagery acquired by very high spatial resolution (VHSR) commercial satellite sensors offer unique capacities in capturing the morphological dynamics of RTSs. The central goal of this study is to develop a deep learning convolutional neural net (CNN) model (a UNet-based workflow) to automatically detect and characterize RTSs from VHSR imagery. We aimed to understand: (1) the optimal combination of input image tile size (array size) and the CNN network input size (resizing factor/spatial resolution) and (2) the interoperability of the trained UNet models across heterogeneous study sites based on a limited set of training samples. Hand annotation of RTS samples, CNN model training and testing, and interoperability analyses were based on two study areas from high-Arctic Canada: (1) Banks Island and (2) Axel Heiberg Island and Ellesmere Island. Our experimental results revealed the potential impact of image tile size and the resizing factor on the detection accuracies of the UNet model. The results from the model transferability analysis elucidate the effects on the UNet model due the variability (e.g., shape, color, and texture) associated with the RTS training samples. Overall, study findings highlight several key factors that we should consider when operationalizing CNN-based RTS mapping over large geographical extents.

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