An Application of the Linear Spectral Unmixing Analysis (LSUA) Method Integrated with GIS for Mapping Glaciers on the Carstensz Peak, Papua
Abstract
Tropical glaciers, such as those in Puncak Jaya, Papua, are among the most climate-sensitive ice masses on Earth, yet their small size, complex topography, and persistent cloud cover hinder accurate monitorin. Conventional threshold-based mapping methods, including the Normalized Difference Snow Index (NDSI), often misclassify debris-covered ice and bright bedrock, limiting their applicability in tropical mountain environments. This study develops and evaluates an integrated Linear Spectral Unmixing Analysis (LSUA)–Geographic Information System (GIS) methodology for high-fidelity mapping of glacier extent and surface composition in Puncak Jaya. Multispectral Landsat 8 OLI imagery was processed using LSUA to generate fractional abundance maps of clean ice, debris-covered ice, supraglacial water, and surrounding terrain. These outputs were integrated with Digital Elevation Models (DEMs) in a GIS framework for glacier area computation, elevation-based change detection, and spatial context analysis. Accuracy assessment using confusion matrices and Root Mean Square Error (RMSE) metrics against high-resolution reference imagery demonstrated that the LSUA–GIS workflow outperformed conventional NDSI mapping, particularly in detecting debris-covered ice, with an overall classification accuracy exceeding 90%. Results revealed continued glacier retreat, with the most significant ice loss occurring at elevations 4.884 MASL. The proposed workflow offers a reproducible and scalable approach for mapping small, fragmented tropical glaciers, providing critical data for climate impact assessment, hydrological planning, and long-term monitoring in remote mountain regions.
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