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A remote sensing method for mapping alpine grasslines based on graph-cut
Licong Liu1, Jin Chen1, Miaogen Shen1
1State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China.
Global Change Biology
|October 31, 2023
Summary
Scientists developed a new remote sensing method to map alpine grasslines on the Tibetan Plateau. This technique accurately identifies the upper limits of alpine grasslands, crucial for understanding climate change impacts.
Area of Science:
- Ecology
- Remote Sensing
- Climate Change Science
Background:
- Climate change alters vegetation boundaries, impacting ecosystems and climate.
- Upper elevational limits of alpine grasslands (alpine grasslines) are poorly understood due to limited data.
- Existing methods lack large-scale, high-resolution estimation of alpine grasslines.
Purpose of the Study:
- To develop and validate a novel, automated remote sensing method for mapping alpine grasslines.
- To determine the spatial distribution and elevational range of alpine grasslines across the Tibetan Plateau.
- To provide a foundation for studying alpine grassline responses to climate change.
Main Methods:
- Automated identification of potential alpine grassline mountains.
- Adaptive feature generation using Landsat reflectance and linear discriminant analysis.
- Graph-cut algorithm integrating Otsu and Canny methods for precise grassline delineation.
Main Results:
- A novel method for 30-m resolution alpine grassline mapping was developed.
- High accuracy was achieved in validation against drone and PlanetScope imagery (R² = .99, .98).
- Alpine grassline elevations on the Tibetan Plateau range from 4038 to 5380 m, with distinct regional patterns.
Conclusions:
- This study presents the first large-scale remote sensing method for mapping alpine grasslines.
- The developed method offers high accuracy and resolution for ecological monitoring.
- Findings provide crucial data for understanding alpine ecosystem dynamics under climate change.
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